Fbp 1005 Web1 - Tagged Op

8/2/2019 Fbp 1005 Web1 - Tagged Op

1/52

Truck Specication or BestOperational Eciency

Gu

ide


2/52

Disclaimer: While the Department for Transport (DfT) has made every effort to ensure

the information in this document is accurate, DfT does not guarantee the accuracy,

completeness or usefulness of that information; and it cannot accept liability for anyloss or damages of any kind resulting from reliance on the information or guidance this

document contains..

2


3/52

ForewordFreight Best Practice is unded by the Department or Transport andmanaged by Faber Maunsell Ltd to promote operational eciency withinreight operations in England.

Freight Best Practice oers FREE essential inormation or the reightindustry, covering topics such as saving uel, developing skills, equipmentand systems, operational eciency and perormance management.

All FREE materials are available to download romwww.businesslink.gov.uk/reightbestpracticeor can be orderedthrough the Hotline on 0300 123 1250. The aim o this guide is to:

Provide a step-by-step guide to help you assess your vehicle needsaccurately

Identiy the main body and trailer options

Identiy the main truck component options

Help you make the right choices or your business

It also includes a checklist o questions you need to ask yoursel at eachstage o the process.

This is an excellent and very detailed guide and should prove a useulaide-mmoire or anyone buying trucks. It should prove particularlyvaluable in the all-important discussions with truck dealers and as a wayo inorming people who may have less requent involvement in theprocess.

Robin Dickeson, Manager, Commercial Vehicle Aairs, The Society o

Motor Manuacturers and Traders Limited

3
http://www.businesslink.gov.uk/freightbestpracticehttp://www.businesslink.gov.uk/freightbestpracticehttp://www.businesslink.gov.uk/freightbestpractice


4/52

4

ContentsForeword 3

Introduction 6The Importance o Good Vehicle Specication 6

Who Should Use this Guide? 6

How this Guide Will Help? 6

How this Guide is Organised 7

Identiy Freight Movement Requirements 8Identiy Business Criteria 9

Identiy Freight Movement Options 9

Compare and Evaluate Options 9

Operator Licensing 10

Types o Trucks Available 11Identiy Basic Truck Types 11

Identiy Main Benets and Features o Truck Types 12

Identiy Body and Trailer Types 13

Ensuring the Truck is Fit or Purpose 17Categorise Type o Delivery to be Undertaken 17

Tailor Vehicle Specication to Match Delivery Type 18

Evaluate Impact o Other Factors on Your Specication 18

Detailed Specication: Core Components 21Chassis 21Suspension 23

Axles 24

Tyres and Wheels 25

Engine 28

Transmission 29

Fuel Tank 30

Cab 31

Body and Trailer 32


5/52


6/52

6

IntroductionThe Importance o Good Vehicle SpecicationThe capital cost o a vehicle may account or less than 50% o its whole-lie cost when uel, maintenanceand other operating expenses are taken into account. Fuel can represent up to 30% o your operationalcosts. Clearly this is a signicant amount and any reduction in uel costs or improvements in operationaleciency can improve the bottom line o your business.

Spending time in developing an accurate and appropriate vehicle specication will help you do this.Ensuring vehicles are closely matched to the tasks they are expected to perorm will improve both uel

and overall operational eciency. This can lead to cost savings, increased protability and reducedenvironmental impact.

On the other hand, inaccurate and inappropriate vehicle specication can result in purchasing a vehiclethat is unsuitable or the task it will be required to carry out. Although such vehicles may be slightlycheaper in terms o initial investment, it may become signicantly more expensive to operate when uelconsumption and maintenance costs are taken into account in the long term. Poor vehicle specication,in some cases, may even lead to breaches o the law and possible legal action.

Who Should Use this Guide?

Everyone who is responsible or acquiring goods vehicles weighing over 3.5 tonnes gross vehicle weight(GVW). This could be feet managers, owner drivers and operational managers. It will equip you with theinormation you need to ensure the most benecial long term outcome when acquiring commercialvehicles.

How this Guide Will Help?

This publication provides independent and authoritative guidance on vehicle specication. It will showyou just how easy it is to produce a t-or-purpose specication and will take you through the key stages

o vehicle specication. Sections 24 cover the basics o vehicle specication, while Sections 67 containmore detailed inormation.


7/52

7

How this Guide isOrganised

This guide provides a step-by-step review othe key stages involved in the decision making

process in speciying a vehicle. Each sectionincludes a checklist o questions.

Section 2 helps you assess your reightmovement requirements and options

Section 3 provides an overview o thedierent types o truck available and theirbasic suitability or particular tasks

Section 4 ocuses more closely on the needto ensure that the truck you acquire is

suitable or the specic environments it willoperate in

Section 5 looks at the main componentso a truck, such as chassis, suspension andaxles, and describes the dierent optionsand their uses

Section 6 looks at additional eatures, suchas aerodynamic design, saety systems andchoice o uel, and discusses the options

availableSection 7 highlights the importance omonitoring a trucks perormance ater ithas entered service to ensure that eciencygains are maximised

The guide also contains our appendices:

Appendix 1 contains a table o typicalwhole lie costs or standard commercialvehicles

Appendix 2 summarises Europeanlegislation on vehicle exhaust emissionlimits

Appendix 3 explains standard terminologyrelating to maximum vehicle weights

Appendix 4 summarises current existingregulations on truck weights anddimensions, and their impact on vehiclespecication


8/52

8

Identiy Freight MovementRequirementsVehicle specication is about selecting the right equipment to undertake the work, ecientlyand saely.

Purchasing a new vehicle represents a signicant nancial commitment in terms o both capital andoperating costs. The ollowing is a set o basic questions which can help you understand your reightmovement requirement:

What are the characteristics o the load in terms o weight and volume?

Where does the load need to be delivered and how ar away is the destination?

How requently are the deliveries required?

Are there delivery or demand fuctuations?

How is the product packaged and how easy is it to handle e.g. is additional equipment required orloading and unloading?

Does the product have any special transport needs e.g. does it need to be temperature controlled,

does it consist o hazardous goods, is animal transportation involved?

What are the driver and crew needs?

Does anything else have to be carried e.g. tools, special equipment?

Is there any need or ancillary machinery e.g. blower, pump?

Are there any other operating constraints e.g. environmental commitments to your OperatorsLicence, or customer or consignee requirements or example, low noise, small vehicle?

The answers to these questions will help you understand your business and transport needs better and

will help you speciy the vehicle appropriate to your needs.


9/52

9

Identiy Business Criteria

It is important to understand the criteria yourchoice o reight option must meet. Althoughthey will be specic to individual cases, suchcriteria could include:

Cost-competitiveness

Consistency with key perormance targetse.g. next-day delivery anywhere in the UK

Ability to ensure installation or assemblyo products at the destination: in someinstances, this will require specialist skills

Reduced environmental impact

This list is not exhaustive and you should spendsome time identiying the criteria that areimportant to your business.

Identiy Freight MovementOptions

You also need to identiy the ull range o optionsavailable or moving your reight. These willinclude:

Procuring a dedicated vehicle, either new,second-hand or leased

Use o a contract haulier

Use o network services or pallets

Parcel post

You should cost all the reight movement options

against a standard unit e.g. per pallet. Dependingon the product, this could be single product orper specied product mix.

Compare and EvaluateOptions

Next you need to identiy the option best suitedto undertaking your transport task. This willinvolve evaluating the options identied in

Section 2.1 and 2.2.

Cost-competitiveness

In most cases, cost will be an important, i not theoverriding, actor that infuences your decision. Itis thereore essential to take the whole-lie costso a purchased vehicle into account. Whole-lie

costs are a combination o:

The initial cost o buying the vehicle

All predicted operating costs, both runningand standing costs

The projected return on disposal

Note: The initial cost minus the projectedreturn on disposal is requently reerred to asdepreciation.

An estimate o whole-lie costs can be madeusing headline costs and published costsrom manuacturers, trade journals and tradeassociations. These can then be combined withoperational costs or your organisation. Whenreplacing an existing vehicle, it is wise to lookat the current costs involved in servicing thedemand. Appendix 1 provides details o typicalwhole lie costs or standard commercial vehicles.

With second-hand or previously used vehicles,the purchase price may be appealing butthe operating costs may be less attractive. Inwhole-lie terms a used vehicle may be moreexpensive and less reliable than a new one. Thepace o technological improvement in the truckmarket has resulted in modern vehicles thatoer greater economy, increased power, loweruel consumption, ewer harmul emissionsand extended service periods that cut vehicledowntime. I you opt or a second-hand vehiclerather than a new one, it is important to select avehicle that meets your business needs as exactlyas possible and has sucient economic lie let toull the operational demands that will be placedon it.

Rather than allocate a considerable amount oresources to purchasing a vehicle many operatorsopt or leasing or contract hire. These options canallow or a vehicle to be on dedicatedlong-term hire to the user. The advantages arethat the vehicle can be regularly updated when

replacement is due with no additional cost tothe user.


10/52

10

From a nancial perspective it reduces the risks,as the item is not shown on the balance sheet.This is particularly important to sectors wheredemand fuctuates.

The major disadvantage o hiring a vehicle,particularly or third party operators, is that itcannot be sold or cash i necessary.

Once your evaluation o each option is complete,you will be in a position to make a well inormeddecision regarding the right solution to yourneeds.

Checklist:

Have you:

Assessed the relevant reight movementrequirement?

Identied all the criteria that your reightmovement option must satisy?

Identied the dierent reight movementoptions that are available?

Compared options and decided whichone best suits your needs?

Operator Licensing

Users o most commercial goods vehiclesweighing over 3.5 tonnes must have a goodsvehicle operators licence. This applies even i youuse a hired vehicle or use the vehicle or one dayonly. The licence authorises an operator to usea maximum total number o motor vehicles and

trailers and a specic operating centre or centreswhere the vehicles are kept when not in use.

For urther inormation and advice contact VOSAon 0300 123 9000 or visit the website at:www.vosa.gov.uk.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/


11/52

11

Types o Trucks AvailableI you have decided that buying a truck is the best option to meet your requirements, you will then needto produce a detailed vehicle specication. This will ensure that the vehicle you buy closely matches thetasks it will undertake.

The rst step towards producing a specication is to develop a clear understanding o the types o vehicleavailable and their main characteristics. This includes identiying the:

Basic truck types

Main benets and eatures o truck types

Body and trailer types

Identiy Basic Truck Types

There are three main categories o truck:

Rigid vehicles (Figure 1) comprise a continuous chassis and two or more axles, and include a motorisedelement and a body.

Figure 1 Rigid Vehicle

Articulated vehicles (Figure 2) have two parts: amotorised drawing unit known as a tractor unitand a mounted trailer. The trailer is attached tothe drawing unit through a specialised couplingusually known as a th wheel coupling.

Figure 2 Articulated Truck

Drawbar combinations consist o a rigid vehiclecoupled to a totally sel-standing trailer via anA-rame drawbar. There are two main types odrawbar trailer: the traditional turntable trailer

(Figure 3) and the central-axle bogie trailer(Figure 4). The trailer is towed directly by arigid vehicle.

Figure 3 Traditional Turntable Trailer
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


12/52

12

Figure 4 Central-axle Bogie Trailer

Identiy Main Benetsand Features o TruckTypes

These three categories o vehicle have dierentcharacteristics and are suited to dierent typeso operations. The regulations that apply tothem generally dier in terms o type o drivinglicence required and the maximum weight theycan legally operate. Appendix 4 has details aboutlegal constraints and requirements.

Rigid Vehicles

These are the most common type otruck. O the 426,000 vehicles above3.5 tonnes in 2003, 309,000 were rigids,(source Department or Transport,Transport Statistics 2003). They are bestsuited to urban operations where size andmanoeuvrability are critical

Rigid vehicles vary rom two axles to our.This depends on the load to be carried andthe environment in which operations occur.Lighter loads, such as consumer goods,

tend to be carried on two-axle vehicles.Heavier loads, such as aggregates, tend tobe carried on our-axle vehicles in order todistribute the load more evenly over theroad

A three-axle rigid usually has one axle atthe ront and two at the rear. Some vehicles,particularly those operated by breweries,have two axles at the ront and one at therear, these are generally reerred to as a

Chinese Six. The two ront axles will be twinsteer i.e. when the vehicle turns both axlesmove to improve manoeuvrabilityand reduce tyre wear

Four-axle vehicles normally have two axlesat the rear and twin steer axles at the ront

Articulated Vehicles

Articulated vehicles eature a chassis truckknown as a tractor unit, which can beattached to a trailer through a specialisedcoupling mechanism, called a th wheel.This has a groove and lock and is bolted tothe chassis. The trailer has a pin tted nearto the ront, known as a kingpin. The pin sitsin the th wheel lock to couple the trailerand can be released by use o a lever. Powerand braking to the trailer are provided viawire connections known as suzies. Thetractor unit can have a number o axlesdepending on the load weight

The trailers used in articulated vehicles havetheir axles towards the rear and rely on thetractor unit to support the ront throughthe th wheel. Landing legs are tted tothe trailers to support the ront when notattached to the tractor unit. These are notalways designed to be load bearing

Drawbar Combinations

The traditional turntable drawbar trailerhas an axle near each end o the trailer. Theront axle is mounted on a sub-rame thatsteers through a turntable rom theA-rame drawbar

In a centre-axle trailer, which requentlyhas two axles coupled closely, the axle issituated in the central area o the trailerand is a non-steer axle. The A-rame pullsthe trailer in the correct direction. This isoten close-coupled with very limited spacebetween the rigid vehicle and the trailer
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


13/52

13

Like articulated vehicles, drawbarcombinations are best suited tolong-distance driving on major trunkroutes, rather than urban centres

Drawbar combinations are currently

increasing in popularity due to thefexibility o being able to change trailersand detach i access is an issue. The largestweight combinations are sometimes knownas roadtrains.

Identiy Body and TrailerTypes

Trucks are usually sub-categorised by body ortrailer type. The ollowing are the most common:

Flat Beds

A fat bed truck or trailer consists o a chassistted with a platorm body. Goods are carriedon the deck and secured by roping and sheetingwhich can be inappropriate or certain cargoesi.e. ragile items or goods which contaminate

easily. Twist locks can be tted to each corner othe fat bed to allow the carriage o containers. Aspecial design allows the trailer to be extendedin the middle section to allow the carriage oabnormally long loads. These extensions areknown as trombones.

Low Loaders

Low loaders are usually built on a semi-trailerdesigned to carry earth moving equipment andmachinery. They are constructed so that the

major part o the load platorm does not extendover, or between, the wheels and the uppersurace is below the top o the tyres. The mostcommon type is the swan-neck trailer. The shapeo the swan-neck acilitates the couplingbetween the tractor and the low bed o the trailervia a right angle joint, as seen rom the side o thetrailer. The swan-neck is detachable and so allowsplant access onto the trailer rom the ront. Rearaccess is restricted by the wheel arches.

Curtainsiders

These consist o a rooed rame with a fexiblecurtain tted to the sides o the body, and caninclude a choice o rear section, either barn dooror a xed wall. Curtainsiders are ideal orpalletised loads that require protection rom theweather. While permitting ecient loading andunloading, as well as nearside and oside access,

they provide less load security than rigid-sidedvehicles.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


14/52

14

Tilts

These are trailers where a metal rame is ttedto a fat bed with a canvas cover known as a tilt.They allow or cargo to be transported coveredbut with good access or loading and unloading.

They are most common on international work.

Box Vehicles and Trailers

Box vehicles comprise a rigid box body, usuallywith solid sides and solid rear-opening doors.Their size and manoeuvrability make them idealor urban multi-drop deliveries (see Section 4). Arigid box can also be tted to trailers as part o anarticulated vehicle. Numerous box body designoptions are available, including solid rear doors,side doors or sliding sidewalls or ease oside access.

Temperature-controlled Bodies

These consist o a rigid box made o insulatedmaterial and designed to carrytemperature-sensitive (chilled or rozen)

products. The bodies can be tted to rigidvehicles or trailers. Most temperature-controlledvehicles operate a reezer or chiller driven by a

separate engine or by the vehicles main engineand generally include electric standby acilities.

Step-rame Trailers

Built on a box trailer, this design optimises theload space area by lowering the rear chassis witha swan-neck or with small rear axles, thusincreasing the volume o the trailer. The uppersurace o the major part o the load platorm isless than 1m above the ground. They are eitherused or low weight goods, such as packagingand hanging garments or in the removal sectorto carry bulky urniture.

Luton

These are basically box vans with an additionalsection constructed over the cab used orancillary equipment and valuables. They aredesigned or large volume low weight goodsand are mainly used or urniture transportand removals.

Double-deck trailers

Double-deck trailers provide two-tier stackingo uniorm pallets on a single trailer by means
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


15/52

15

o a second deck. The second deck can be xedor moving to give greater fexibility or loadingand unloading. This kind o trailer may providea cost-eective solution or high-volume,low-weight loads. It is important to considerthe eect that this type o vehicle will have oninrastructure, or example, their extra heightmay make them unsuitable where the routesinclude low bridges, and they may also requirespecialised loading and unloading equipment.See Appendix 4 on legal constraints on themaximum height o vehicles.

Road Tankers

These vehicles have a permanent tank tted to a

chassis or the transportation o liquids, gases orpowders. Road tanker loading/unloadingmethods include gravity eeds, blowers andvacuuming. Tank bodies are requently tted totrailers and rigid vehicles, oten multi-axle tomaximise weight distribution. Some tankoperations include an internal liner to enable thetransportation o mixed loads without the needto fush out the tank.

Skeletal Trailers

These consist o a chassis trailer without apurpose-built body. They are designed to carryshipping containers that are usually secured tothe chassis via twist locks set at each lowercorner o the container.

Tippers

Tippers comprise o an open-top body that can,via a hydraulic ram, tip rearwards to unloadwhen the tailgate is released. Typical loadsinclude earth and stone. As these can be heavyloads, multi axle vehicles are requently used.Articulated tippers can be used to improvefexibility and have a higher overall weight. SeeAppendix 4 or legal constraints.

Demountable Swap Body Systems

With this system, the chassis is designed tocarry multiple containers. Goods can be loadedindependently o the truck at the centralwarehouse, enabling driver time to be ullyutilised driving the vehicle. Oten included indrawbar combinations, demountable containerscan be arranged in any conguration withinlegal limits. Managed eectively, signicant

operational eciencies can be achieved. Forexample, a number o ully laden containers canbe dropped overnight at a sub-depot by a singlevehicle or next day delivery by small urbanvehicles. Absence o intermediate goodshandling saves time and labour, reduces risk odamage and reduces the need or warehousingat satellite depots. Landing legs are tted to swapbodies which allow the host vehicle to be drivenunder the body to couple it to the chassis.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


16/52

16

Checklist:

Have you:

Identied the basic types o truck

available?

Identied the main benets and eatureso each type?

Developed an understanding o bodyand trailer types and their uses?
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


17/52

17

Ensuring the Truck is Fit or PurposeThe next step is to build up a more detailed picture o what your vehicle will be used or and to identiywhich o the vehicle body and trailer designs described in Section 3 provide the best match. This willrequire a thorough knowledge o the goods to be transported and a clear understanding o deliverydestinations, in terms o geographical location and the delivery inrastructure they are equipped with,or example, types o materials handling equipment (MHE) and docking heights, etc.

For example, i the goods to be moved weigh eight tonnes, t on 14 pallets and require a daily journeyo around 300 miles, a vehicle designed or urban high street multi-drop delivery (see 4.2 below) or anarticulated vehicle operating at 44 tonnes will not generally be the most appropriate or cost-ecientoption. A rigid vehicle between 15 and 17 tonnes GVW, on the other hand, is likely to be the best

solution. Remember, a contract haulier consolidating your load with others may be cheaper.

To ensure the vehicle is suitable you will need to:

Categorise the type o delivery to be undertaken

Tailor vehicle specication to match delivery type

Evaluate the impact o other actors on your specication

Categorise Type o Delivery to be Undertaken

Deliveries perormed by commercial vehicles can be divided into a number o categories.

The main ones are:

Urban Delivery

Includes destinations in cities, towns and also villages. This is the most common type o delivery, wherelocations can be characterised by high volumes o trac, limited parking and the need to unload thevehicle at the kerbside, which can be dangerous to both driver and pedestrians. I your customers aresmall retailers, most o them will be in this kind o location, or example, on high streets or inshopping precincts.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


18/52

18

Urban Multi-drop Delivery

This is where a vehicle carries out more than onedelivery in an urban location. They are aectedby the same pressures as urban delivery, but to agreater extent due to more activity.

Retail Park Delivery

Some o your customers may be located inretail parks outside town centres. These sites arenormally purpose built and generally includebetter access and acilities (e.g. loading bays)than urban deliveries.

Wholesale or Manuacturing

Delivery

Wholesalers or manuacturers premises may belocated in cities, towns and out-o-town businessparks, which creates the needs or a fexiblevehicle in order to service all three types o site.They tend to be big deliveries by the very naturethat wholesalers and manuacturers tend tobuy in bulk. Facilities can vary rom a purposebuilt 24-hour distribution centre equippedwith adjustable height loading bays to a smallindustrial unit in a city centre location which

only unloads by hand.

Tailor Vehicle Specicationto Match Delivery Type

Once you have identied the type o deliveryyour vehicle will carry out, you should rame yourvehicle specication to take this into account.

Urban Delivery and UrbanMulti-drop Delivery

Rigid vehicles with good manoeuvrability wouldbe suitable or this kind o delivery. They can copebetter with the trac and restrictions on parkingor unloading deliveries on the high street. Whenparking, vehicle length will also be a major issue.Moreover, i the vehicle is too big, it may not beable to access locations down narrow streets or

where weight restrictions apply.I the vehicle has rear access only, there maybe occasions where there is not enough space

behind it or unloading. I the vehicle has sideaccess, this will probably need to be on bothsides as unloading directly onto the street canbe very dangerous and unloading onto thepavement can be hazardous to pedestrians,especially i the vehicle door opens outwardsrather than sliding laterally.

Retail Park Delivery

An articulated vehicle or drawbar combinationwill be suited to this kind o delivery. In retailparks, most o your customers will havededicated loading and unloading bays andthere will be ew size restrictions.

Wholesale or Manuacture Delivery

Articulated vehicles would be better suited tobulk loads such as deliveries to wholesalers ormanuacturers. These locations normally includegood access to both pick-up and delivery points.I the deliveries are to purpose-built locations,the delivery area will usually be equipped withgood acilities e.g. loading bays designed withrear access to loads in mind. Where deliverypoints have mixed acilities, a combination o rearand side access is recommended. I the productsbeing delivered are suitable, curtainsiderscan provide good fexibility. However, whereproducts require temperature controls, rearaccess may be the only practical choice.

Rural or O-road Delivery

These may be locations which are airly isolatedwith poor access. It may mean a vehicle will haveto cope with rugged conditions and at the sametime be small enough to handle country lanes.Multiple-drive axles should be considered iavailable.

Evaluate Impact oOther Factors on YourSpecication

A range o additional actors could have animportant bearing on the overall design o the

vehicle you purchase.

Changes in Product or Packaging
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


19/52

19

The potential or changes to the product orproduct packaging during the vehicles lieshould be taken into account at the specicationstage and may infuence the choice o vehicle. Itis dicult to predict this, however, close contactwith your market and customer may help youdo this.

Driver Vision

Most commercial vehicles have blind spotsand pedestrians do not always act as expected.Drivers need to be ully aware o what ishappening around them at all times. Extra mirrorsand rear viewing cameras may be essential, inaddition to reversing bleepers, or areas o highrisk to pedestrians.

Security

Vehicle security is a particular issue when thedriver is delivering unloaded goods and thevehicle is out o the drivers sight or a period otime. The value o the load will be a key actor.Precious metals will normally only be moved inspecially designed security vehicles, whereasscrap metal is requently transported in open-topvehicles as potential thet is less o an issue.

Special Travelling Requirements

For some products, temperature sensitivity maymean the load space needs to betemperature-controlled. Hal-carcasses beingdelivered to butchers will normally travel onhanging rails in the vehicle body, dictating rearaccess only. Chicken, by contrast, is normallyboxed so either rear or side access is suitable.Note: the greater the number o access points,the greater the likelihood o temperature gain.A larger rerigeration unit may be needed

to compensate.

Tail Lits

I the destination has no loading bay, it maybe important or your vehicle to be equippedwith a tail lit to help loading and unloading opalletised goods, or instance. Manual handlingequipment or a orklit truck may also need tobe carried with the vehicle. The need or a tail litcould mean that a vehicle has to have rear access.As a general principle, the larger a truck in termso GVW, the lower the unit cost o transporting

its load i.e. pence per mile per tonne o payloadmoved, providing it is ull. However, lowerkerbside weight (i.e. the weight o the vehicle inroad-going condition, inclusive o water, uel, oil,spare wheel, spares and tools, without the load)will also generally mean improved uel economy,resulting in lower payload costs.

However, as Sections 3 and 4 have shown, awide range o actors will aect the design andultimately the overall operational eciency othe vehicle you purchase. It is thereore necessaryto base your vehicle specication on a balanced

judgement that takes all relevant actors intoaccount.

Checklist:

Have you:

Categorised the type o delivery thatthe vehicle will undertake?

Shaped your vehicle specication tomatch the type o delivery?

Evaluated how other actors will aectyour vehicle specication?

Table 1 over lea provides a very simple overviewo the suitability o some truck types orparticular applications.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


20/52

20

Table 1 Overview o Truck Suitability or Particular Applications

7.5t fatbed truck

7.5tcurtain

sider

7.5t boxvehicle

Multiaxle rigid

vehicle

Articvehicle

Drawbarcombination

Artic &double

deck trailer

Demountablesystem

Urban(General haulage)

Urban Multi-drop(Pannelised load)

Urban(security need)

Urban

(high-density load)

Long-distancetrunking


(low density cargo)


(high density cargo)

Inter-city

= Suitable Vehicle
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


21/52

21

Detailed Specication:Core ComponentsI you have ollowed the steps outlined in the previous chapters, you should now have developed a good

idea o the type o truck that will meet your specic requirements.

Unlike cars and vans, which are usually sold as complete packages, commercial vehicles tend to becustomised. Two vehicles may have a similar chassis, but their overall design and load capacity may becompletely dierent, with one designed or long-distance motorway work and the other or low-mileage,o-road duties.

Manuacturers ranchise dealers are equipped with sotware packages to help their customers producedetailed vehicle specications. Nevertheless, you will need to make sure the sales person understandsyour precise requirements, or the range o vehicle components. This means you must have developed aclear idea o the components you need.

The evaluation o your requirements should cover nine key areas:

Chassis

Suspension

Axles

Tyres/wheels

Engine

Transmission

Fuel tank

Cab

Body and trailer

Chassis

Key Points:

How many axles will the vehicle need?

How long will the body o the vehicleneed to be?

What ancillary equipment will yourtruck require?

Will the chassis provide sucienttorsional stiness?
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


22/52

22

Background

The purpose o the chassis is to locate the axles,power unit, running gear and cab to orm thestructural skeleton or the engine drive train,uel tanks and batteries. The chassis is the

undamental platorm on which the vehicle isdesigned and essentially has two longitudinalsteel channels with a series o cross-members.

Options

The major actors that need considering are:

Number o axles: The number o axles willdetermine the overall carrying capacity o the

vehicle. Generally the heavier the load, the moreaxles are needed. For a more detailed explanationo the axle considerations see Section 5.3 Axles.The body: The body length will have an eect onthe length o chassis specied. It is important toensure the body sits on the chassis both in termso length and ttings. For example, overhangis restricted to 60% o the wheelbase or rigidvehicles. For a more detailed explanation o bodyconsiderations see Section 5.9 Body and Trailer.

Ancillary equipment: Certain additionalequipment may be required or a vehicle, orexample, grabs, cranes, liting gear or tail lits.The chassis must be able to accommodatethese in terms o space and weight. For a moredetailed explanation o this see Section 6.3Ancillary Equipment.

Specic Issues

Torsional stiness: Certain equipment (grabs andlorry loaders cranes) or a requirement to operatethe vehicle under severe conditions may require

additional torsional stiness i.e. strength to stopthe chassis bending under duress or load beyondthat provided by the chassis. This can be achievedby adding urther beams to the existing chassiseither longitudinally or laterally. To minimisethe weight o reinorcement, choosing a chassiswith a relatively high torsional stiness may beadvantageous.

Body mountings: Chassis body mountings areimportant details. Body mountings manage thedierential movement between the body, whichis generally rigid and the chassis, which fexeswith road movement to avoid structural damageto both elements.

I the chassis is unlikely to suer major fexingi.e. it is to operate only on good road suraces,

a rigid mounting bracket (see Figure 5) may besucient. Where the vehicle is to operate inconditions more likely to cause chassis fexing(e.g. o-road) a fexible body mounting (seeFigure 6) is recommended. It is important tocheck that fexible mountings are not over-tightened during maintenance, as this willreduce their fexibility.

Figure 5 Rigid Body Mounting Bracket

Figure 6 Flexible Front Body Mounting
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


23/52

23

Suspension

Key Points:

Is smoothness o ride a priority?

How important are vehicle noise andweight?

Do you need access to higher authorisedmaximum weights?

Is the vehicle going to operate in poorconditions?

BackgroundA vehicles suspension system absorbs theimpacts caused by travelling over an irregularsurace. The choice o suspension system isgenerally determined by the nature o thevehicles operation.

Options

There are three main types o suspension:

Parabolic or taper lea springs

Air suspension

Rubber suspension

Figure 7 Parabolic or Taper Lea Springs

Figure 8 Multi-lea Spring

The parabolic or taper lea spring with dampersand anti-roll bar is the most common orm osuspension or trucks. The modern taper leaspring (Figure 7) normally consists o a singleor minimal number o lea springs. These arereplacing the multi-lea springs (Figure 8) which

were prone to riction and damage.

Figure 9 Air Suspension

Air suspension (Figure 9) is a common alternativeto the taper lea springs. Frequently reerred

to as road riendly suspension (RFS), it hastwo major benets: access to the increasedmaximum authorised weights (see Appendix 4);and smoother ride characteristics essential orprotecting ragile goods e.g. sensitive electricalproducts. However, air suspension is more costlythan taper lea springs and is slightly heavier,thereby reducing the vehicles overall payload.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


24/52

24

Figure 10 Rubber Suspension

Rubber suspension (Figure 10), like airsuspension, provides improved ridecharacteristics over the taper lea springsuspension, but it does not have the ability toadjust the ride height like air suspension.Rubber suspension is also heavier than taperlea spring suspension, again reducing vehiclepayload.

Specic Issues

Sensitivity and toughness: Suspension needsto combine sensitivity with toughness. Wherepotential damage to goods is an issue, orexample a load o computers or resh ruit, mostoperators will speciy air suspension in orderto protect the cargo. Rubber suspension isbetter suited to muckaway (earthmoving/wastedisposal) operations where the protection o theproduct is less important. Rubber suspension isless likely to be damaged by the terrain, whereasan air suspension can burst i it is punctured. The

disadvantage is that more o the orce o the loadis transerred rom the vehicle to the road, henceit is less environmentally riendly.

Ride height: Air suspension provides fexibilitywith respect to road travel heights. The acilityto alter travel heights can avoid grounding thetrailer when travelling over rough terrain or whentravelling onto a erry. It also enables the truckbody to be raised or lowered or loading andunloading, e.g. when docking at warehouses

to ensure a fat surace between the bed o thetrailer and the dock.Furthermore, air suspension can lower anarticulated unit when hitching up a trailer. This

allows the th wheel to slide easily to lock ontothe kingpin, without having to increase theheight o the trailer using landing legs.

Axles

Key Points:

What are your vehicles load capacityand power requirements?

Is your truck likely to run empty or light?

Do you need to maximisemanoeuvrability?

Background

Axles distribute the weight rom the truck andits payload onto the road surace. Due to thecomplex legislation on permitted axle weights,they play a key role in determining the grossweight o the vehicle. Axle weight is dened asthe total weight transmitted to the road by allthe wheels on one axle.

Vehicles will requently be reerred to as a 6 x4 or a 6 x 2, or example. This is a simple wayo identiying the number o visible (i.e. outer)wheels and the number o driven wheels on thevehicle. In the example o a 6 x 4 the vehicle willhave three visible wheels on each side, makinga total o six visible wheels running rom threeaxles; i two wheels on either side are on poweredaxles, this will make a total o our driven wheels.

Options

Four types o axle are ound on commercialvehicles:

Dead axle

Drive axle

Lit axle

Steer axle

Dead axles do not have power or steeringcapabilities and are used on non-powered trailersand on trucks where there is a need to increasecarrying capacity.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


25/52

25

Drive axles are powered axles incorporating thenal drive, or dierential unit, that provides theacility or the driveline to turn through a rightangle and power the wheels. The drive axlealso incorporates the constant gear reductionmechanism or the transmission system. It isimportant to have the correct specication toachieve the right power to weight ratio and ueleconomy. I you have a choice o drive ratios orthe drive axle, you should research the optionsto ensure the correct match. Where ultra-lowgear ratios are required, this is normally achievedby speciying a low nal drive ratio. However,to achieve optimum uel eciency, engineperormance must be matched to the operation(see Section 5.5 on driveline specication orurther inormation).

Lit axles are used during periods o empty, orlight, running. Ideally, trucks should run ullyloaded all the time but, in reality, a certainamount o empty running is inevitable. For amulti-axle vehicle, the acility to lit and retaina non-driven axle clear o the ground whenpartially loaded can be economic in terms oboth tyre lie and uel use. Lit axles can alsotranser weight temporarily to the drive axle orincreased traction.

To increase carrying capacity, powered axles areadded to multi-axle vehicles. These can either beadded in ront o (pusher) or behind (tags) thedrive axle.

Steer axles are traditionally ront axles, bothprimary and secondary, which are steerableand occasionally driven. Increasingly, rear traileraxles are being given a steer unction to improvemanoeuvrability.

Specic Issues

Avoiding axle and gross overloads: A crucialactor aecting the choice o axles is the payloadand the weight transerred through the axles.I the total axle capacity equals the GVW, thevehicle does not have any load latitude or sparecapacity. This means that, when the vehicle is atits maximum weight with a load, the load mustbe evenly distributed over the axles.

Having a total axle capacity which exceeds theGVW will provide load latitude and help avoidaxle overloads (see Appendix 4). Even where

vehicles have load latitude, it is essential tomaintain proper weight distribution to avoid axleoverloads. I in doubt, check load congurationsat a public weighbridge or consider investingin axle-weighing equipment. The latter is otenbuilt into the chassis o the vehicle and shouldthereore be specied at the time o buying thevehicle. I the vehicle is to be used o-road it isimportant to ensure that the equipment installedis robust enough to withstand the extra wearand tear.

Tyres and Wheels

Key Points:

Is cost an overriding issue?

How important is length o tyre lie?

Is weight-saving a key consideration?

What load-carrying ability do you need?

Are you aiming to maximise ueleciency?

Is the vehicle likely to operate under

adverse conditions?

Background

Very ew operators speciy tyre preerence whenordering a new vehicle. However, correct tyreselection is o paramount importance to saetyand to operating costs. Tyre selection also aectthe tachograph and speed limiter calibration.

A tyre perorms a number o unctions:

It supports the vehicles weight anddistributes it over the road surace

It contributes to the overall ability o thesuspension to absorb impacts

It provides the required level o adhesionbetween the road and wheel or traction,braking and steering in wet and dryconditions
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


26/52

26

It helps provide required perormancesaely up to the vehicles top design speed

It helps the vehicle to run true and providegood straight-line directional stability

It should oer the minimum rolling

resistance to the vehicles motion andminimise the uel required to drivethe vehicle

It should be recyclable and relatively easyto dispose o

It should perorm quietly

It should achieve reasonable economic lie,while minimising whole-lie costs.

Tyre selection will represent a compromisebetween these sometimes conficting needs.

Options

There are two main types o tyres radial and,the largely historic, cross-ply.

Radial tyres: These are the main type o tyre inuse. They have a fexible side wall which permitsbetter road contact and lower rolling resistance

leading to better uel consumption and bettercornering and grip, particularly in wet conditions,through reduced side defection that keeps moreo the tread on the road. Todays truck market isdominated by radial tyres, which have around80% longer lie than cross-ply tyres.

Cross-ply tyres: These are sometimes reerredto as diagonal-ply and eature a hard sidewall,which has less road contact than a radial tyre.

Other types o tyre include:

Re-grooved tyres: Modern radial tyres aredesigned to be re-grooved which essentiallyextends their lie and improves road traction.However, or saety reasons, many operators usere-grooved tyres only on rear non-steer axles.The rolling resistance o re-grooved tyres is thesame as new radial tyres. Re-grooving radial tyresis recommended by most tyre manuacturers,rstly to re-establish the correct groove width o

the tyre as it wears and so give good traction, andsecondly to extend tyre lie. In some cases, thetyre may be re-grooved more than once, but in allcases must still comply with legal requirements.

Re-moulded or re-treaded tyres: Re-mouldsare made rom used tyre casings which have hotvulcanised rubber added to orm a newtyre tread. Re-treads are strips o tyre tread,which are glued or bonded to the used tyre. Thebonded treatment is usually a better and morereliable process. The lie expectancy o these tyresis around 20% less than new radial tyres.

Although re-moulded or re-treaded tyres can betted to any axle, operators oten t them to rearnon-steer axles only. For saety reasons, manywill not t re-grooved, re-treaded or re-mouldedtyres to steer axles, although the law does notprohibit this. It is also good practice only to ttyres with the same characteristics to asingle axle.

Super-singles or wide tyres: These are denedas having an area o contact with the road at least300mm in width. They are now commonplaceon steer and trailer axles and are gradually beingused on drive axles. Super-singles have a numbero advantages: less weight than twin tyres thesuper-single generally also has lower unsprungweight and generally provides or a smootherride than twin tyres; lower rolling resistance,leading to better uel consumption; and a biggercontact area, giving better grip and traction.

However, they may not always provide loadcarrying comparable to twin tyres and a singlepuncture may mean the truck cannot reach asaety area.

Lower rolling resistance tyres: A tyres rollingresistance decreases as its tread depth reduces.Manuacturers have been striving to producelower rolling resistance tyres because o the uel-saving benets. Initial trials have shown somepositive results, with uel consumption reduced

by around 7-8%. Reductions are most likely to beapparent i the vehicle has multiple axles, i it isengaged in long-distance trunking and i all axlesare tted with these tyres. Some in-use trials haveshown tread wear rates inerior to standard tyres,so any potential savings should take into accounttyre replacement costs. For more inormation,see the Freight Best Practice case study Save Fuelwith Lower Rolling Resistance Tyres.

Ultra-wide low-prole tyres: Tyres known as495/45R22.5 are claimed to oer a 17% reductionin rolling resistance, compared to twin tyres on adrive axle. However, service depots may not beable to support vehicles using these tyres.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


27/52

27

Alloy wheels: Alloy wheels can be purchased asoriginal equipment costing around 250 eachmore than a standard steel wheel but typicallyhave a weight saving o 41%-52% compared withthe steel equivalent, depending on wheel size.Apart rom cosmetic reasons, tting alloy wheelsis recommended only i payload is a critical issue.Alloy wheels are more prone to damage thanthe harder steel wheels and are not ideal or useon construction sites or o-road activity, wheredamage can easily occur.

Specic Issues

Tyre maintenance: Modern truck tyres aredesigned to withstand arduous operatingconditions, rom stop-start town deliveries tohigh-speed trunking on motorways and acrossinternational road networks. They will alsoperorm eciently and give economic lie over awide range o terrains and in a variety o weatherconditions. To achieve this, it is essential thattyres are careully inspected and maintainedregularly. One o the most common tyre deects

is under-infation. This causes additional uel useand premature tyre wear, and can jeopardisesaety.

Adverse conditions: There are certainsubstances and situations that can considerablyshorten the lives o tyres made rom naturalor synthetic rubbers. The main substancesare mineral oils and greases, brake fuid,concentrated nitric and sulphuric acid and someorganic salts. Tyres can also be damaged by

roadside kerbs. It is advisable to equip vehiclesthat regularly visit petrochemical sites with tyresresistant to the type o products ound there. Forvehicles constantly scung kerbs e.g. dustcarts

tyres are available with special rubbing bands onboth sidewalls. When the wear indicator on theoutside band is exposed the tyre can be rotatedso that the inner wall becomes the outside aceo the tyre.

Spare wheel policy: These days, spare wheelsare rarely tted as they represent an extra costand dead weight and are vulnerable to thet.Moreover, the saety concerns involved in a driverchanging a wheel by the roadside mean it is saerand more ecient to arrange or a tyre companyto deal with punctures and tyre problems.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


28/52

28

Engine

Key Points

What weight will the engine need to pull?Will your vehicle be used or longdistance or local work?

What road speeds will the truck travel at?

Will you run ancillary equipment romthe main engine?

Background

When selecting the engine, your aim shouldbe to choose one which matches your overalloperational power requirements as this willensure optimum uel economy.

Important actors to consider when speciyingan engine or a particular vehicle are:

The power to weight ratio should permitthe vehicle to operate at maximum torque

output or most o its driving pattern (ormore inormation see Specic Issues laterin this section)

Higher power output does not necessarilymean lower uel consumption

Fuel consumption benets should beassessed in whole-lie cost terms

Options

Diesel engine: This is the most common typeused in commercial vehicles. Unlike the petrolengine, which is a spark compression engine, thediesel engine is essentially a compression ignitionengine. The naturally aspirated engine draws airinto the cylinder during the induction stroke atambient temperature and pressurised to a ratioo 14:1 or more. To achieve increased enginepower, the pressure is increased through turbocharging and the use o inter-coolers.Because o the technically advanced nature

o modern trucks, engine options exist. Themost recent innovation in diesel engines isthe introduction o common rail uel systems.

Here, computers control the injection processi.e. electronic engine management, and deliverthe uel under high pressure to individuallyelectronically controlled injection valves. This hasresulted in signicantly higher-output engineswith improved uel eciency.

Specic Issues

Power output and torque - clarication oterminology: When speciying an engine,misunderstandings between the terms poweroutput and torque are common.

Power output is measured as the rate oundertaking work. The common powermeasurement or commercial vehiclesis horsepower. This is based on a horsesability to move 33,000 pounds 1 ootin 1 minute! The metric equivalent to 1horsepower is 746 watts.

Torque is the orce put out by the engineat the end o the crankshat used to drivethe vehicle. The torque produced by anengine will vary at dierent engine speeds.Torque is thereore important to achievingoptimum engine eciency. I optimumtorque can be achieved at low engine

speed, overall uel eciencies will improveconsiderably compared to an enginerunning at maximum revolutions

Driveline specication: The driveline is thetranser o power rom the engine through thegearbox and drive shat to the drive axle. Thehigher gear ratios are used or top speed, but atthe cost o power or perormance. Matching theengine output in terms o both power outputand torque to the gearbox ratios and the drive

axle ratio is absolutely essential or optimisinguel consumption.

Studying engine perormance curves that showpower output, torque and brake-specic uelconsumption plotted against engine speed willtell you much about the suitability o a particularspecication or your own operation. In generalterms, you should choose higher-power enginesand higher nal drive ratios or long-distancework. Vehicles that spend most o their time onlocal work will generally be more economicali they have less power, ewer gear ratios and alower nal drive ratio.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


29/52

29

To help operators with their choices on drivelines,gearbox ratios, etc. most manuacturers havecomputer programs that can compare variousengine, gearbox and nal drive ratio options.These will orecast the vehicles theoreticalperormance, including uel consumption. Youcan help ensure that the program arrives at theright answer by supplying as much accurateinormation as possible about your operation.You can also try to obtain a demonstrator vehicleas close as possible to your specication.

Matching engine power and torque to

ancillary equipments operational needs:When speciying ancillary equipment to bedriven rom a gearbox-mounted powertake-o (PTO), it is important to consider the gearratio to be used. Modern engines have ecient

power and torque curves starting at around1,000rpm. This provides an ideal position to setthe PTO gearing or optimum uel economy.Lower gearing may produce additional power todrive the ancillary equipment, but at higher uelconsumption.

Second-hand vehicles: A particular point to noteis that a used vehicles exact power rating or naldrive ratio may not be obvious. The vehicle could,or example, have a long-distance specication,

making it relatively uneconomical or local work.Note: i the vendor cannot produce evidenceo the exact specication, it is worth quotingthe chassis number to a ranchised dealer. Thisshould give access to the manuacturers originalbuild specication.

Reducing emissions: This is a topic o particularrelevance to buyers o second-hand vehicles.The introduction o European exhaust emissionstandards, known as Euro 1, 2, 3, 4 and 5, has

had a considerable impact on the maximumlevel o harmul pollutants produced rom dieselengines. European legislation aims to reducesignicantly carbon dioxide (CO2), hydrocarbon(HC), oxides o nitrogen (NOx) and particulateemissions rom trucks. (See Appendix 2 or moredetails, including the years o introduction o thevarious standards.) The act that these reductionsare being achieved alongside improvementsin power output and uel consumptiondemonstrates the major advances being made indiesel engine technology.

Local air quality and Low Emission Zones(LEZs) are moving up the agenda and also have

implications or vehicle emissions. Operatorsneed to develop an understanding o theseissues now and consider how the introduction oexclusion zones will aect the choice o enginespecication.

Some vehicles tted with equipment, usuallyon the exhaust system, that reduces particulatelevels can obtain a Reduced Pollution Certicate(RPC) i the vehicle meets certain compliancelimits. RPCs, which permit the certied vehiclea lower rate o Vehicle Excise Duty, must berenewed on a yearly basis ollowing an emissionstest. It is important to check the enginespecication as to whether it qualies.

Contract hire and operating leases: Whenacquiring a vehicle through contract hire or

an operating lease, you may nd that the bestvehicle or your operation is, or instance, alow-power tractor unit with a day cab but thatthe monthly lease payment is lower or a morepowerul unit with a sleeper cab. This is mainlya refection o the desirability o the vehicle inthe used market at the end o the lease term. It isimportant to consider the dierence in uel costsbetween the two specications saving 20 amonth on the lease rate may cost 40 a month inuel costs.

Transmission

Key Points

Will your vehicle be used or nonmotorway driving?

How important is reduced driver atigueand improved driver concentration?

Do you need to minimise journey timesand maximise uel eciency?

Background

A gearbox is needed to disengage the enginerom the wheels and to match engine speed,power and torque to a required task enabling thevehicle to pull away or allowing it to accelerate,climb gradients or reverse. In eect, the gearboxacts like a lever. The lower the gear, the greaterthe leverage and the higher the tractive eort,subject to engine characteristics.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/


30/52

30

Options

Manual gearboxes: This type o gearbox iscommon or long distance work where gearchanges are inrequent. This is a proven orm otechnology and is the most popular type in use

today, although automated shits are becomingmore popular.

Automatic gearboxes and semi-automatic

gearboxes: Automatic gearboxes weredeveloped to reduce the need or constant gearchanges. This is done completely through a ullautomatic or partly through a semi-automaticgearbox. The choice depends upon the extent ogear changes.

They tend to be used in vehicles on requent

stop/start operations, or example, airportvehicles and reuse trucks. This reduces thewear and tear on the driveline and driveratigue. Automatic boxes help improve driverconcentration or emergency service vehiclesand provide a smoother engine operation whichcan improve uel economy. They are increasinglyspecied or longer distance work, as thetechnical developments now oer most driversimproved uel consumption.

Specic Issues

Cruise control: This is becoming a popularoption or commercial vehicles, particularly ormotorway/long-distance operations. Cruisecontrol can result in less engine and drivelinewear and reduced driver atigue. It will also helpoptimise the electronic control systems abilityto deliver the appropriate amount o uel orany given situation, improving uel eciency.By setting the cruise control to correspond to

the best specic uel consumption speed o theengine, average uel consumption can be cut.

For ree copies, contact the Freight BestPractice Hotline on 0300 123 1250 orvisit the website atwww.businesslink.gov.uk/

reightbestpractice.

Fuel Tank

Key Points

Will your vehicle be used or long

distance work?

Is vehicle weight a key issue?

Will your truck be tted with ancillaryequipment?

Background

The size o the uel tank can be an importantdecision when speciying a truck. I the vehicleis designed or long-distance work, the standarduel tank may not be able to carry enough uel tocomplete the journey. I uel is bunkered on site,this will oten cost less than the retail price onorecourts and may be an incentive to tlarger tanks.

Options

Size o tank: The size o the uel tank requireddepends upon the type o operation and theamount o uel required. A long distance vehiclewill generally have a larger tank than an urbandistribution vehicle, as the range is higher.

Extra capacity: The tting o an additionaltank to a vehicle is popular or internationaloperations as the requency o uelling acilitiesin certain regions is limited. This can either be anextra tank next to the existing one or a tank ttedhorizontally on the chassis, known as a belly tank.

Specic Issues

Implications or payloads: Increasing tankholding capacities will reduce a vehicles overallpayload capabilities. This may be critical in termso the nal size and specication o the vehicle. Agallon o diesel weighs 3.86kg, so 100 gallons willadd 386kg to the vehicles kerbside weight.Ancillary equipment: I the vehicle is tted withancillary equipment, such as a reezer/chillier unit

that is not driven directly rom the engine, thisequipment may need a separate uel tank.
http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/http://www.vosa.gov.uk/h

Fbp 1005 Web1 - Tagged Op

Documents

Transcript of Fbp 1005 Web1 - Tagged Op