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Basic functions of the tyre as a connection element in vehicle-road

interaction

The tyres have a major contribution to motor vehicle performances like:

traction;

braking;

steering;

comfort;

fuel saving;

safety.

So, a tyre must provide high adherence, proper ride characteristic and stiffness, low rolling resistance andnoise, high reliability (fatigue and separation and wear resistance (including bruise, cutting, cracking andtearing resistance.

!eside the tyre properties, the vehicle"road interaction is affected also by the motor vehicle and road

surface properties. Some influence factors on these components, from the vehicle"road interaction pointof view, are further presented.

Tyre properties are affected by:

type of tyre carcass (and breaker construction;

si#e and shape of the tyre;

si#e and shape of the contact area between tyre and road;

materials properties " especial of the rubber compounds;

tread pattern design;

tread wear state;

inflation pressure.

$otor vehicle properties are affected by:

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load carrying capability;

body design and aerodynamics by loading imposed on each tyre in straight running;

suspension construction by load transfer in traction, braking and cornering;

speed capability;

tractive tor%ue available;

steering control type and wheel alignment;

braking mechanism type (locking or anti"lock systems.

&oad surface properties are affected by:

surface hardness;

friction coefficient under dry conditions;

macro and micro surface te'ture (rough, smooth, polished or sharp;

water drainage;

wear characteristic with use;

contamination (water, ice, snow, dust, mud or sand;

temperature.

nfortunately, referring to the tyre, not all desired performances could be reached in the same time. )ore'ample, a tyre with a good adherence on dry road could provide a worth one on a wet road or on ice. *nthe same idea some very simplified connections between tyre characteristics and its performances arepresented in table +.

Table 1- Simplified connections between tyre characteristics and tyre performance

Tyrecharacteris

tic

Influence

paramet

er

Tyre performances

Adheren

ce

Ridecomfo

rt

Rollingresistan

ce

Wearresistan

ce

ois

e

Tyrecarcass

and breakerdesign

Tyrerigidity,

,

Tyre si#eontactarea,

, ,

https://www.tut.fi/ms/muo/tyreschool/moduulit/moduuli_8/hypertext_1/1/1_1.html#tablehttps://www.tut.fi/ms/muo/tyreschool/moduulit/moduuli_8/hypertext_1/1/1_1.html#table

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&ubbercompoundsproperties

&ubberhysteres

is,

Treadpatterndesign

-atternhigh,

,

/&ed arrows reflect positive influence.

Steel Belts

Steel belts are a common feature in many rubber tires, helping to further improve

handling and resistance to wear and tear; they often improve gas mileage as well.

In addition to steel, other materials, such as rayon and berglass, are used in belted

tires.

Composition

All rubber tires have a rubber and fabric composition, which is molded

to the size needed to t the various rim sizes on vehicles. Additionally,

chemicals are added to the rubber to improve its life and performance. Steel

wires also are built into the tires, near their inner edge, to help them better

stay on the metal rims.

Bonding

Rubber tires, with their e!ible "ualities, bond to the minor

irregularities in the surface of a road, providing higher friction that helps tires

grip the road better. #hat serves to improve handling, stability and bra$ing

capabilities as well.

Strength

Rubber, in addition to being e!ible, is highly durable, even more so

after a tire goes through the vulcanization process. Rubber tires are strong,

able to hold the air pressure needed for them to operate properly and to

resist puncture from ob%ects such as sharp stones in the road.

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Wear and Tear

#he chemical processing used in the manufacture of tires ma$es an

already tough product even better. #hose chemicals ma$e tires more

resistant to wear and tear. #he chemicals also stop tires from melting from

e!cessive heat, or crac$ing in e!treme cold. In addition, this treatment slows

the aging process of the rubber tires, ma$ing them last longer than they

would untreated.