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IS 12159:2007

Indian StandardMETHOD OF EVALUATION OF ACCURACY OFPARAMETERS OF STEERING GEOMETRY OF

AUTOMOTIVE VEHICLES( First Revision)

ICS 43.040.50

0 BIS 2007BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

September 2007 Price Group 2

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Automotive Primemovers, Transmission and Steering Systems and Internal Combustion Engines SectionalCommittee, TED 2

FOREWORDThis Indian Standard (First Revision) was adopted by the Burew of Indian Standards, after the draft finalized bythe Automotive Primemovers, Transmission and Steering Systems and Internal Combustion Engines SectionalCommittee had been approved by the Transport Engineering Division Council.The overall performance of an automotive vehicle is a function of performance of its various components, systems,instrumentation, etc. The steering geometry is an important parameter for the evaluation of performance of thesteering system of an automotive vehicle. For steering effort, reference maybe made to IS 11948:1999 Automotivevehicles Steering effort Method of evaluation (@t revision).This standard was first published in 1987. This revision has been undertaken to upgrade it with the latestdevelopments in the field. In this standard the following changes have been incorporated:

a) Castor angle is given in detail along with figure, andb) All parameters contributing to steering geometry have been provided.

The composition of the Committee responsible for formulation of this standard is given in Annex A,For the purpose of deciding whether a particular requirement of this standard is complied with, the final value,observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2:1960Rules for rounding off numerical values (revised). The number of significant places retained in the rounded offvalue should be the same as that of the specified value in this standard.

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Indian StandardMETHOD OF EVALUATION OF

IS 12159:2007

ACCURACY OFPARAMETERS OF STEERING GEOMETRY OF

AUTOMOTIVE VEHICLES( First Revision)

1 SCOPEThis standard gives theaccuracy of parameters

method of evaluation ofof steering geometry of

automotive vehicles like cars, buses, jeeps and trucks.2 REFERENCE2.1 The following standard contains provision whichthrough reference in this text, constitutes provision ofthis standard. At the time of publication, the editionindicated was valid. All standards are subject to revisionand parties to agreements based on this standard isencouraged to investigate the possibility of applyingthe most recent edition of the standard indicated below:

IS No. Title9435:2004 Terms and definitions relating to

dimensions of road vehicles otherthan 2 and 3 wheelers (first revision)

3 TERMINOLOGY3.1 Unless otherwise stated, the definitions of term usedshall be according to IS 9435.3.2 Castor AngleCastor angle is the acute angle between the verticalline passing through the centre line of the steered wheeland the real or imaginary swiveling axis of the stubaxle in the longitudinal plane (see Fig. 1).

P ~~

FIG. 1 CASTOR ANGLE

The distance between two points p and q is theprojection on to a plane parallel to the longitudinalmedian plane (of the vehicle) of the acute angle formedby the vertical and the real or imaginary swivelingaxis of the stub axle. It is positive when p is ahead of qin the direction of normal travel.3.3 Wheel Lock AngleWheel lock angle is the acute angle in the horizontalplane between two centre lines of the steered wheelprojected onto the horizontal plane when the wheel isin the straight ahead position and when the wheel issteered to its extreme position. The term, inner wheellock angle, shall mean the wheel lock angle for the leftwheel, when steered for a left turn and right wheel,when steered for a right turn. Similarly outer wheellock angle shall mean wheel lock angle for left wheel,when steered for a right turn and right wheel, whensteered for a left turn.3.4 Camber Angle (see Fig. 2)The acute angle formed by a vertical line and themidplane of the wheel. The angle is positive when thewheel leans out at the top.

NOTE This angle is measured in the unladen condition ofthe vehicle.

/\ \\ I

FIG. 2 CAMBER ANGLE

1

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IS 12159:20073.5 Toe-in (see 3.5.1 and 3.5.2)3.5.1 Toe-in LengthThe ends of the horizontal diameters of the interiorcontours of the rims corresponding to the same axleare the apices of an isosceles trapezium. The differencebetween the length of the rear base and that of theforward base of the trapezium is the toe-in, thedifference being positive when the wheels are closertogether in front than behind, and negative in thecontrary case (see Fig. 3).

t

FIG. 3 TOE-IN LENGTH3.5.2 Toe-in AngleThe angle formed by the horizontal diameter of thewheel and the longitudinal median plane (of thevehicle) or the acute angle formed by the vertical planeG passing through the axis of the axle-pin and a verticalplane Hperpendicular to the longitudinal median plane(of the vehicle) (see Fig. 4).

a .-

FIG. 4 TOE-IN ANGLE

4 PREPARATION OF VEHICLE4.1 The vehicle shall conform in all its parts andcomponents to the design and/or production series asapplicable.4.2 The tyres shall be inflated to the pressurerecommended by the vehicle manufacturer.

4.3 Unless otherwise mentioned, the vehicle shall beloaded to the rated gross vehicle weight (GVW), withthe load distribution between the axles being thatrecommended by the manufacturer corresponding tothe rated loads.4.4 The vehicle shall be stationary and all the wheelsshall be resting on a level horizontal surface.5 ESSENTIAL PARAMETERS OF STEERINGGEOMETRY OF AUTOMOTIVE VEHICLE5.1 While checking the following parameters, theaccuracy of measurement shall be as indicated belowunless otherwise agreed to between the manufacturerand the purchaser:

Parameter(1)

King pin inclinationCamber (to be measured inladen or unladen conditionas recommended by themanufacturer)Castor angleWheel lock angleToe-in

Toe-out

Turning radius

Turning clearance circlediameter

Accuracy ofMeasurement,

(2)1515

1560

As per manufacturersrecommendation in mmAs per manufacturersrecommendation, in mmAs per manufacturersrecommendationAs per manufacturersrecommendation

5.1.1 The ranges of various parameters shall be asspecified by the manufacturer.5.2 The wheel lock angle shall meet the followingconditions:

a)

b)

c)

There shall be stoppers to ensure that thewheels cannot be steered to a value higherthan the specified value.When the wheels are turned to the wheel lockangle, the smallest clearance between the tyreand the nearest point of interference is notless than 15 mm.When the wheels are turned to the wheel lockangle, a margin of quarter turn of steeringwheel is left before the maximum travel ofsteering gear is reached.

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ANNEX A(Foreword)

COMMITTEE COMPOSITIONAutomotive Primemovers, Transmission and Steering Systems and Internal Combustion Engines Sectional

Committee, TED2Organiur:iorr

Automotive Research Association of India, Pune

Ashok Leyland Ltd, Hosur

Association of State Road Transport Undertakings, New DelhiAutomotive Components Manufacturers Association of India,

New DelhiBajaj Auto Ltd, Pune

Bharat Earth Movers Ltd, Mysore

Central Institute of Road Transport, PuneClutch Auto Ltd, Faridabad

Controllerate Quality Assurance (HV), Chennai

Cummins India Ltd, Punt

DGS&D (Quality Assurance), Ahrnedabad

Either Tractors, New Delhi

Greaves (Cotton) Ltd, Pune

HMT Ltd (Tractor Division), Pinjore

Indian Diesel Engine Manufacturers Association, Agra

Indian Institute of Petroleum, Dehradun

Indian Institute of Technology (IIT), New DelhiKinetic Engineering Ltd, PuneKirloskar Oil Engines Ltd, PuneMahindra & Mahindra, Nasik

Maruti Udyog Ltd, GurgaonMinistry of Heavy Industries & Public Enterprises, New Delhi

Ministry of Road Transport & Highways, New DelhiMotor Industries Co Ltd, Bangalore

Ordnance Factory Board, Kolkatta

Rajkot Engineering Association, Rajkot

Rane Power Steering Ltd, Pudukkotai

Represerrtutive(s)SHRI M. K. CHouDHAiu (Chairrnars)

SHRI N. V. MARATHE (Alternate)SHRI M. N. GAMAL KUMAR

SHIN S. K. RAJU (Alfernate)SHRI SIWALISHRI RAJIV M~NDKE

SHRI G. P. BANERJI (Alternate)SHRI S. B. RAO

SHRJ T. M. BALARAMAN (Alternate)SJ{RI L. NAMPERUMAL

SHRI R. H. MURALIDHAR (Alternate)SHRI A. S LAKRASHRI S. G. MANJ

SHNJ S. C. SHARMA (Alternate)SHRI G. VENKATAKRISHNAN

SHRI C. B. MADANA MANOHARAN (Alternate)GENERAL MANAOER (TECH CENTRE)

SHRI S. G. KINARE (Alrernate)SHRJ V. K. SRIDHAR

SHRI P. M. WANJARI (Alternate)DR SATYAMURTHY

SHRI S. K. SEAM (Alternute)SHRI W. N. KHATAUKAR

SHRI A. S. PATIL (Alternate)SHRI OM PRAKASH

SHRI ATOL KUMAR (A hernate)SHRI R. P. AGARWAL

SHRI RAVJ AGARWAL (Alternate)DR S. K. SJNGHAL

SHRI NISHAN SINCiH (Alternate)THE DJRECTORSHRI R. V. GOWNDSHRI C. G. RANADEDR MATHEW ABRAHAM

SHRJ S. RAMAMMURTHY(Alternate)SHRI SHIVA KUMARSHRI V. C. MATHUR

SHRI B. N. DAS (Alternate)DIRECTOR (TECHNICAL)SHRI L. M. NAIK

SHRJ K. JAYANNA(Alternate)SHRI G. S. MARWAHA

SHRJ V. C. VERMA (Alternate)SHRI B. U. MEHTA

SHRI M. R. DOSHJ (Alternare)SHRI S. RADHAKRJSHNAN

3

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IS 12159:2007Organization Representative(s)

Simpson & Co Ltd, Chennai SHRI S. MURALIDHARANSHRI S. JANARDHANAN(Alternate)

Society of Indian Automobile Manufacturers, New Delhi SHRI K. K. GANDHISHRI SUMITSHARMA (Alternate)

Sona Steering Systems Ltd, New Delhi SSSRIT. K. PALTata Motors Ltd, Pune SHRI V. LAXMINARAYANANSHRI S. R. GoIw(Akernafe)Tractor Manufacturers Association, New Delhi SHRI T. C. GOPALAN

SHRI S. BALASUBRAMANIAN(Alternate)Vehicle Research and Development Establishment, Ahmednagar SHRI T. K. KAMBLE

SHRIB. L. WAGH (Alternate)Volvo India Pvt Ltd, Chennai SHRIARNE KNABEN

SHRI S. V. SUDERSON (Alternate)BIS Directorate General SHRIRAKESH KUMAR, Scientist Fand Head (TED)

[Representing Director General (Ex-officio)]Member SecretarySHRI P. S. MUJRAL

Scientist E (TED), BISSUPPLIEDBYBOOKSUPPLYBUR

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Bureau of lndian StandardsBIS is a statutory institution established under the Bureau of lndiun Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification of goodsand attending to connected matters in the country.CopyrightBIS has the copyright of all its publications. No part of these publications may be reproduced in any formwithout the prior permission in writing of BIS. This does not preclude the free use, in the course ofimplementing the standard, of necessary details, such as symbols and sizes, type or grade designations.Enquiries relating to copyright be addressed to the Director (Publications), BIS.Review of Indian StandardsAmendments are issued to standards as the need arises on the basis of comments. Standards are also reviewedperiodically; a standard along with amendments is reaffirmed when such review indicates that no changes areneeded; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standardsshould ascertain that they are in possession of the latest amendments or edition by referring to the latest issue ofBIS Catalogue and Standards : Monthly Additions.This IndianStandardhas been developedfromDoc: No. TED 2 (452).

Amendments Issued Since Publication

Amend No. Date of Issue Text Affected

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