IS 12159: Method of evaluation of accuracy of parameters of steering geometry of automotive vehicles

2007·1 MB·English

by  Bureau of Indian Standards

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IS 12159 (2007): Method of evaluation of accuracy of
parameters of steering geometry of automotive vehicles [TED
2: Automotive Primemovers]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee””
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IS 12159:2007

Indian Standard
METHOD OF EVALUATION OF ACCURACY OF
PARAMETERS OF STEERING GEOMETRY OF
AUTOMOTIVE VEHICLES
( First Revision)
ICS 43.040.50

0 BIS 2007
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002

September 2007 Price Group 2
Automotive Primemovers, Transmission and Steering Systems and Internal Combustion Engines Sectional
Committee, TED 2
FOREWORD
This Indian Standard (First Revision) was adopted by the Burew of Indian Standards, after the draft finalized by
the Automotive Primemovers, Transmission and Steering Systems and Internal Combustion Engines Sectional
Committee had been approved by the Transport Engineering Division Council.
The overall performance of an automotive vehicle isafunction ofperformance of its various components, systems,
instrumentation, etc. The steering geometry is an important parameter for the evaluation of performance of the
steering system ofan automotive vehicle. For steering effort, reference maybe made toIS 11948:1999 ‘Automotive
vehicles — Steering effort — Method of evaluation (@t revision)’.
This standard was first published in 1987. This revision has been undertaken to upgrade it with the latest
developments in the field. In this standard the following changes have been incorporated:
a) Castor angle is given in detail along with figure, and
b) 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 orcalculated, expressing the result of atest oranalysis, shall berounded off inaccordance with IS 2:1960
‘Rules for rounding off numerical values (revised)’. The number of significant places retained in the rounded off
value should be the same as that of the specified value in this standard.
IS 12159:2007
Indian Standard
METHOD OF EVALUATION OF ACCURACY OF
PARAMETERS OF STEERING GEOMETRY OF
AUTOMOTIVE VEHICLES
( First Revision)
1SCOPE The distance between two points p and q is the
projection on to a plane parallel to the longitudinal
This standard gives the method of evaluation of
median plane (of the vehicle) of the acute angle formed
accuracy of parameters of steering geometry of
by the vertical and the real or imaginary swiveling
automotive vehicles like cars, buses, jeeps and trucks.
axis of the stub axle. It is positive when p is ahead of q
2REFERENCE in the direction of normal travel.
2.1 The following standard contains provision which 3.3 Wheel Lock Angle
through reference in this text, constitutes provision of
this standard. At the time of publication, the edition Wheel lock angle is the acute angle in the horizontal
indicated was valid. All standards are subject torevision plane between two centre lines of the steered wheel
and parties to agreements based on this standard is projected onto the horizontal plane when the wheel is
encouraged to investigate the possibility of applying in the straight ahead position and when the wheel is
the most recent edition ofthe standard indicated below: steered to its extreme position. The term, inner wheel
lock angle, shall mean the wheel lock angle for the left
IS No. Title
wheel, when steered for a left turn and right wheel,
9435:2004 Terms and definitions relating to
when steered for a right turn. Similarly outer wheel
dimensions of road vehicles other
than 2and 3wheelers (first revision) lock angle shall mean wheel lock angle for left wheel,
when steered for a right turn and right wheel, when
3TERMINOLOGY steered for a left turn.
3.1 Unless otherwise stated, the definitions ofterm used
3.4 Camber Angle (see Fig. 2)
shall be according to IS 9435.
The acute angle formed by a vertical line and the

3.2 Castor Angle
midplane of the wheel. The angle is positive when the

Castor angle is the acute angle between the vertical wheel leans out at the top.
line passing through the centre line of the steered wheel
NOTE — This angle is measured in the unladen condition of
and the real or imaginary swiveling axis of the stub the vehicle.
axle in the longitudinal plane (see Fig. 1).
/\ \
\ I
P ~~

FIG. 1CASTOR ANGLE FIG. 2 CAMBER ANGLE
1
IS 12159:2007
3.5 Toe-in (see 3.5.1 and 3.5.2) 4.3 Unless otherwise mentioned, the vehicle shall be
loaded to the rated gross vehicle weight (GVW), with
3.5.1 Toe-in Length
the load distribution between the axles being that
The ends of the horizontal diameters of the interior recommended by the manufacturer corresponding to
contours of the rims corresponding to the same axle the rated loads.
are the apices of an isosceles trapezium. The difference
4.4 The vehicle shall be stationary and all the wheels
between the length of the rear base and that of the
shall be resting on a level horizontal surface.
forward base of the trapezium is the toe-in, the
difference being positive when the wheels are closer 5 ESSENTIAL PARAMETERS OF STEERING
together in front than behind, and negative in the GEOMETRY OF AUTOMOTIVE VEHICLE
contrary case (see Fig. 3).
5.1 While checking the following parameters, the
accuracy of measurement shall be as indicated below
unless otherwise agreed to between the manufacturer
and the purchaser:
t
Parameter Accuracy of
Measurement,
(1) (2)
King pin inclination 15’
Camber (to be measured in 15’
laden or unladen condition
as recommended by the
FIG. 3 TOE-IN LENGTH
manufacturer)
3.5.2 Toe-in Angle
Castor angle 15’
The angle formed by the horizontal diameter of the Wheel lock angle 60
wheel and the longitudinal median plane (of the
Toe-in As per manufacturer’s
vehicle) or the acute angle formed by the vertical plane
recommendation in mm
Gpassing through the axis of the axle-pin and avertical
Toe-out As per manufacturer’s
plane Hperpendicular to the longitudinal median plane
recommendation, inmm
(of the vehicle) (see Fig. 4).
Turning radius As per manufacturer’s
recommendation
Turning clearance circle As per manufacturer’s

diameter recommendation

5.1.1 The ranges of various parameters shall be as
specified by the manufacturer.
.-
a 5.2 The wheel lock angle shall meet the following
conditions:
a) There shall be stoppers to ensure that the
wheels cannot be steered to a value higher
than the specified value.
FIG. 4 TOE-IN ANGLE
b) When the wheels are turned to the wheel lock
4 PREPARATION OF VEHICLE angle, the smallest clearance between the tyre
and the nearest point of interference is not
4.1 The vehicle shall conform in all its parts and
less than 15 mm.
components to the design and/or production series as
c) When the wheels are turned tothe wheel lock
applicable.
angle, a margin of quarter turn of steering
4.2 The tyres shall be inflated to the pressure wheel is left before the maximum travel of
recommended by the vehicle manufacturer. steering gear is reached.
ANNEX A
(Foreword)
COMMITTEE COMPOSITION
Automotive Primemovers, Transmission and Steering Systems and Internal Combustion Engines Sectional
Committee, TED2
Organiur:iorr Represerrtutive(s)
Automotive Research Association of India, Pune SHRI M. K. CHouDHAiu (Chairrnars)
SHRI N. V. MARATHE(Alternate)
Ashok Leyland Ltd, Hosur SHRI M. N. GAMAL KUMAR
SHINS. K. RAJU (Alfernate)
Association of State Road Transport Undertakings, New Delhi SHRI SIWALI
Automotive Components Manufacturers Association of India, SHRI RAJIV M~NDKE
New Delhi SHRI G. P. BANERJI(Alternate)
Bajaj Auto Ltd, Pune SHRI S. B. RAO
SHRJT. M. BALARAMAN(Alternate)
Bharat Earth Movers Ltd, Mysore SJ{RIL. NAMPERUMAL
SHRIR. H. MURALIDHAR(Alternate)
Central Institute of Road Transport, Pune SHRI A. S LAKRA
Clutch Auto Ltd, Faridabad SHRI S. G. MANJ
SHNJS. C. SHARMA(Alternate)
Controllerate Quality Assurance (HV), Chennai SHRIG. VENKATAKRISHNAN
SHRI C. B. MADANAMANOHARAN(Alternate)
Cummins India Ltd, Punt GENERALMANAOER(TECH CENTRE)
SHRI S. G. KINARE(Alrernate)
DGS&D (Quality Assurance), Ahrnedabad SHRJV. K. SRIDHAR
SHRI P. M. WANJARI(Alternate)
Either Tractors, New Delhi DR SATYAMURTHY
SHRI S. K. SEAM (Alternute)
Greaves (Cotton) Ltd, Pune SHRI W. N. KHATAUKAR
SHRIA. S. PATIL(Alternate)
HMT Ltd (Tractor Division), Pinjore SHRI OM PRAKASH
SHRIATOL KUMAR(Ahernate)

Indian Diesel Engine Manufacturers Ass ociation, Agra SHRI R. P. AGARWAL

SHRI RAVJAGARWAL(Alternate)
Indian Institute of Petroleum, Dehradun DR S. K. SJNGHAL
SHRINISHANSINCiH(Alternate)
Indian Institute of Technology (IIT), New Delhi THE DJRECTOR
Kinetic Engineering Ltd, Pune SHRI R. V. GOWND
Kirloskar Oil Engines Ltd, Pune SHRI C. G. RANADE
Mahindra & Mahindra, Nasik DR MATHEWABRAHAM
SHRJS. RAMAMMURTHY(Alternate)
Maruti Udyog Ltd, Gurgaon SHRI SHIVAKUMAR
Ministry of Heavy Industries & Public Enterprises, New Delhi SHRI V. C. MATHUR
SHRIB. N. DAS (Alternate)
Ministry of Road Transport & Highways, New Delhi DIRECTOR(TECHNICAL)
Motor Industries Co Ltd, Bangalore SHRI L. M. NAIK
SHRJK. JAYANNA(Alternate)
Ordnance Factory Board, Kolkatta SHRI G. S. MARWAHA
SHRJV. C. VERMA(Alternate)
Rajkot Engineering Association, Rajkot SHRI B. U. MEHTA
SHRIM. R. DOSHJ (Alternare)
Rane Power Steering Ltd, Pudukkotai SHRI S. RADHAKRJSHNAN
3
d
IS 12159:2007
Organization Representative(s)
Simpson & Co Ltd, Chennai SHRIS. MURALIDHARAN
SHRIS. JANARDHANAN(Alternate)
Society of Indian Automobile Manufacturers, New Delhi SHRIK. K. GANDHI
SHRISUMITSHARMA(Alternate)
Sona Steering Systems Ltd, New Delhi SSSRIT. K. PAL
Tata Motors Ltd, Pune SHRIV. LAXMINARAYANAN
SHRIS. R. GoIw(Akernafe)
Tractor Manufacturers Association, New Delhi SHRIT. C. GOPALAN
SHRI S. BALASUBRAMANIAN(Alternate)
Vehicle Research and Development Establishment, Ahmednagar SHRIT. K. KAMBLE
SHRIB. L. WAGH (Alternate)
Volvo India Pvt Ltd, Chennai SHRIARNE KNABEN
SHRI S. V. SUDERSON(Alternate)
BIS Directorate General SHRIRAKESH KUMAR,Scientist ‘F’and Head (TED)
[Representing Director General (Ex-officio)]
Member Secretary
SHRI P. S. MUJRAL
Scientist ‘E’ (TED), BIS

4
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This IndianStandardhasbeendevelopedfromDoc: No. TED2(452).
Amendments Issued Since Publication
Amend No. Date of Issue Text Affected
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