Bsi bs au 050 2 5c 1996 (1999)

BRITISH STANDARD AUTOMOBILE SERIES

Tyres and wheels —
Part 2: Wheels and rims —
Section 5c: Specification for road
wheels manufactured wholly or partly
of cast light alloy for passenger cars

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BS AU
50-2.5 c:1 996


BS AU 5 0-2.5c:1 996

Committees responsible for this
British Standard

The preparation of this British Standard was entrusted to Technical
Committee AUE/4, Tyres and wheels for road vehicles, upon which the
following bodies were represented:
Agricultural Engineers’ Association
Automobile Association
British Industrial Truck Association
British Pressure Gauge Manufacturers’ Association
British Rubber Manufacturers’ Association
Confederation of Passenger Transport UK
Department of Transport
Freight Transport Association
Institute of Road Transport Engineers (Inc)

Motor Cycle Industry’s Association of Great Britain Ltd.
Motor Industry Research Association
National Tyre Distributors’ Association
Retread Manufacturers’ Association
Road Haulage Association Ltd.
Society of Motor Manufacturers and Traders Ltd.

This British Standard, having
been prepared under the
direction of the Engineering
Sector Board, was published
under the authority of the
Standards Board and comes
into effect on
1 5 April 1 996
© BSI 07- 1 999

Amendments issued since publication

First published July 1 976

Amd. No.

Second edition April 1 996

The following BSI references
relate to the work on this
standard:
Committee reference AUE/4
Draft for comment 94/71 3765 DC

ISBN 0 5 80 25 366 X

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Date

Comments


BS AU 5 0-2.5 c:1 996

Contents

Page
Committees responsible

Inside front cover

Foreword

ii

5. 1

Scope

1

5. 2

References

1

5. 3

Definitions

1

5. 4

Materials

1

5. 5

Protection of magnesium alloy castings and finished wheels

2

5. 6

Tests on completed wheels

2

5. 7

Documentation

2

5. 8

Marking

2

5. 9

Valve holes

3

Annex A (normative) Quality control/test schedule

6

Annex B (normative) Validation procedure

6

Annex C (normative) Conformity of production

7

Annex D (normative) Tyre fitting test. Procedure for the

introduction of new or modified rim profiles

7

Annex E (normative) Dynamic cornering fatigue test

7

Annex F (normative) Dynamic radial fatigue test

8

Annex G (normative) Impact test

8

Annex H (normative) Testing of finishing systems

9

Annex J (informative) Guidance on certain aspects of
wheel attachment systems

11

Figure 1 — Typical wheels

3

Figure 2 — Wheel nomenclature

4

Figure 3 — Valve holes

10

Figure G. 2 — Machine calibration method

11

List of references

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Figure G. 1 — Wheel impact machine

Inside back cover

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BS AU 5 0-2.5c:1 996

Foreword

This S ection of BS AU 5 0 has b een p rep ared b y Technical C ommittee AUE /4. It

sup ersedes BS AU 5 0- 2 . 5 : 1 976, which is withdrawn.
The increas ed p erformance of p ass enger cars led in the 1 97 0s to the us e for the
road wheels of light alloys , generally of aluminium or magnes ium, which offer a
favourab le strength to weight ratio. The firs t edition of BS AU 5 0 - 2 . 5 was
p ub lis hed in 1 97 6 to ensure that the quality of des ign and p roduction was
adequately controlled.
This new edition incorp orates Amendment 1 and Amendment 2 to
BS AU 5 0- 2 . 5 : 1 97 6, and introduces technical changes as follows:
— in

E .1

a maximum length of moment arm is s p ecified;

— in

E .3

the value for

— in

G.3

an additional op tion for the tyre has b een allowed for original

È

and the exp res sion for

R

have b een changed;

equip ment wheels .
References to other s tandards have also b een reviewed and, where p oss ib le, are
now undated. This new edition does not, however, cons titute a full revis ion of the
standard.
Tyre, wheel, rim and valve requirements are given in the following Parts and
S ections of BS AU 5 0 :
—

Part 1: Tyres;

—

Section 0: General;

—

Section 1: Car tyres;

—

Section 2: Commercial vehicle tyres;

—

Section 3: Off-the-road tyres;

—

Section 4: Agricultural tractor and machine tyres;

—

Section 5: Industrial vehicle tyres;

—

Section 6: Motorcycle tyres;

—

Section 7: Moped tyres;

—

Section 8: Code of practice for the storage of tyres, inner tubes and flaps;

—

Part 2: Wheels and rims;

Section 0: General (including terms and definitions, and construction and
workmanship);

—

—

Section 1: (Withdrawn);

Section 2: Specification for dimensions of wheel naves and hub centres for
commercial vehicles;
—

— Section 3: Specification for road-wheel nuts, studs and bolts for commercial
vehicles;

Section 5: Specification for road wheels manufactured wholly or partly of
cast light alloy for passenger cars;

—

Section 6: Specification for road wheels manufactured wholly or partly of
light alloy for mopeds and motor cycles;

—

— Section 7: Code of practice for the selection and care of tyres and wheels for
commercial vehicles;

Section 8: Code of practice for the selection and care of wheels for passenger
cars (including caravans and light trailers);

—

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Part 3: Valves;

—

Section 1: Specification for valve dimensions;

—

Section 2: Tyre valve threads 5V1, 5V2, 6V1 and 8V1 ;

—

Section 3: Tyre valve threads 9V1, 10V2, 12V1 and 1 3V1;

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BS AU 5 0-2.5 c:1 996

— Section 4: Tyre valve threads 8V2, 1 0V1, 11 V1, 13V2, 1 5V1, 16V1, 17V1 ,
17V2, 17V3, 19V1 and 20V1;
—

Section 5: Dimensions for ISO core chamber No. 1 for tyre inflation valves;

—

Section 6: Dimensions for ISO core chamber No. 2 for tyre inflation valves;

Section 7: Code of practice for the selection and care of tyre inflation valves
for passenger cars (including caravans and light trailers);
—

— Section 8: Code of practice for the selection and care of tyre inflation valves
for commercial vehicles;
—

Part 4: Rim profiles and dimensions;

—

Section 1 : Car rims;

—

Section 2: Commercial vehicle rims;

—

Section 3: Off-the-road rims;

—

Section 4: Agricultural tractor and machine rims;

—

Section 5: Industrial vehicle rims;

—

Section 6: Motorcycle rims;

—

Section 7: Moped rims.

A British Standard does not purport to include all the necessary provisions of a
contract. Users of British Standards are responsible for their correct application.
Compliance with a British Standard does not of itself confer immunity
from legal obligations.

Summary of pages

This document comprises a front cover, an inside front cover, pages i to iv,
pages 1 to 1 2, an inside back cover and a back cover.
This standard has been updated (see copyright date) and may have had
amendments incorporated. This will be indicated in the amendment table on
the inside front cover.

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BS AU 50-2.5c:1 996

5.1 Scope
This Section of BS AU 50- 2 specifies performance

5.3.4
wheel loading

requirements and methods of test for wheels with

the mass supported by a wheel

any structural element of light alloy for use on all

5.3.5

passenger cars and three- wheeled motorcycles

specific application wheel

having an unladen weight greater than 255 kg.
NOTE

Requirements for light alloy wheels for use on

three- wheeled motor cycles having an unladen weight less
than 255 kg are given in BS AU 50- 2. 6.

5.2 References

a wheel designed to meet the specification
determined by the vehicle manufacturer

5.3.6
general application wheel
a wheel designed so that one basic casting may be

5.2.1 Normative references

used for wheels to be utilized for a variety of vehicles

This Section of BS AU 50 incorporates, by dated or

5.3.7

undated reference, provisions from other

radiological standard

publications. These normative references are made
at the appropriate places in the text and the cited
publications are listed on the inside back cover. For
dated references, only the edition cited applies; any
subsequent amendments to or revisions of the cited
publication apply to this Section of BS AU 50 only

when incorporated in the reference by amendment

permanent radiographic record of the basic design of
wheel showing the minimum acceptance standard
as agreed between the founder and the wheel
manufacturer

5.4 Materials

or revision. For undated references, the latest

The materials used to manufacture cast light alloy

edition of the cited publication applies, together

road wheels shall be such that the performance

with any amendments.

requirements of this standard are met, see Annex A.

5.2.2 Informative references
This Section of BS AU 50 refers to other

NOTE

The materials used should preferably conform to either

BS 1 490 or BS 2970, however in order to permit the development
and application of alloys not included in the above standards,

publications that provide information or guidance.

other light alloys may be used.

Editions of these publications current at the time of

Cast light alloys, whether or not included in

issue of this standard are listed on the inside back

BS 1 490 or BS 2970, shall have suitably specified

cover, but reference should be made to the latest

chemical compositions, mechanical properties and

editions.

5.3 Definitions
For the purposes of this Section of BS AU 50 the
definitions given in BS AU 50- 1 . 0 and BS AU 50- 2. 0

other physical requirements which shall be defined
and agreed between the founder and the wheel
manufacturer with particular attention being given
to the influence of age hardening and stress
corrosion.

apply, together with the following.

Whatever the light alloys used in the manufacture

See also Figure 2.

of road wheels conforming to this Section of

5.3.1
centre member (disc, spider or spoked)
the connection between the vehicle hub and the
wheel rim

BS AU 50, the inspection and quality control for cast
aluminium and cast magnesium alloys shall
conform to BS 1 490 or BS 2970 respectively,
including the additional inspection and test
procedures for analysis, together with optional

5.3.2

procedures as agreed between the founder and the

nave

wheel manufacturer.

central portion of centre member, where the wheel
mounting face and fixing features are usually
located

NOTE

In the case of BS 2970: 1 989 this corresponds to the

classification QC/TS (quality controlled to a test schedule) . In the
case of BS 1 490: 1 988 this corresponds to supplementary test
code A, with other test codes as agreed in the test schedule.

5.3.3

Materials other than cast light alloys used to make

offset

parts of a composite wheel shall conform to the

the distance between the mounting face of the nave
and the centre- line of the rim (see Figure 1 ). The
distance is termed positive (inset) when the

appropriate British Standards (see A.3 ). In making
use of such materials, cognizance shall be taken of
the compatibility of dissimilar materials.

mounting face is outboard of the rim centre- line and
negative (outset) when inboard of the rim
centre- line

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BS AU 5 0-2.5c:1 996

If suitable British Standard specifications are not
available, the requirements for the materials shall
be specified and agreed between the founder and the
wheel manufacturer.

5 .5 Protection of magnesium alloy
castings and finished wheels
The protective treatment against corrosion shall be
applied by the founder and/or the wheel
manufacturer. All surfaces on magnesium wheels
shall be fully protected.

Tyre fitting test

5.6.4.2

Wheel rim profiles not conforming to the
requirements of BS AU 50- 4. 1 shall conform to the
criteria for acceptance specified in Annex D.
5.6.4.3 Dynamic cornering fatigue test
(separate wheel)

Wheels shall be subj ected to the dynamic cornering
fatigue test described in Annex E, and shall conform

to the criteria for acceptance specified in E.4
and E.5 .
5.6.4.4

Dynamic radial fatigue test (separate

5 .6 Tests on completed wheels

wheel)

5.6.1 Design approval

Wheels shall be subj ected to the dynamic radial

To conform to the requirements of this Section of
this standard, wheels shall first have the design
validated by test samples, which shall demonstrate
conformity to 5.6.4 . Any change in detail design or

fatigue test described in Annex F, and shall conform
to the criteria for acceptance specified in F.4
and F.5 .
5.6.4.5

Impact test (separate wheel)

alloy specification shall be followed by revalidation.

Wheels shall be subj ected to the impact test

Revalidation shall also follow any change in the

described in Annex G, and shall conform to the

finishing system which results in changes in the

criteria for acceptance specified in G.7 and G.8 .

residual surface stress condition.

5.6.4.6

NOTE

In the case of wheels for general application, test

specimens may be selected, using the procedure described in
Annex B.

5.6.2 C onformity of production

Finishing systems

Inboard parts of all wheels, the rim area covered by
the tyre, whether polished or not, and any other
unpolished areas, shall be protected to conform to
the requirements of Annex H. A finished wheel (not

For sampling rates, see Annex C. The minimum

test panels) shall be used for the salt spray test

rate of testing should be in accordance with the

specified in H.2.1 .

recommendations given in C.1 .

It shall be the responsibility of the wheel

The results of the tests shall be interpreted, and

manufacturer and the retailer to include with the

re- examined or retesting carried out, in accordance

sale of polished wheels a warning of the effects of

with the criteria specified in C.2 .

corrosion on the polished areas, and to make

5 .6.3 Preparation of test wheels

recommendations regarding protection.

Tests shall be carried out on fully- finished wheels

NOTE

representative of normal production except in those
cases where permanent coatings have been applied
which cannot be removed by simple chemical
processes without damage to the wheels, this

Guidance on some aspects of the design of wheel

attachment systems is given in Annex J.

5.7 Documentation
Chemical analysis certificates and/or hot metal

coating removal being necessary to permit

suppliers’ analysis certificates, chemical analysis

penetrant- dye crack detection to be carried out. In

records, mechanical test records, heat treatment

these exceptional cases it shall be permissible to test

furnace charts, dimensional records and records of

uncoated wheels, provided that the wheels have

conformity to the performance tests specified

undergone the complete heat- stoving cycle

in 5 .6.4 appertaining to all wheels shall be retained

applicable to the coating process.

for a minimum period of 6 years.

5 .6.4 Performance requirements
5 .6.4.1

General

All wheels manufactured to this standard shall
conform to the following performance requirements.

5.8 Marking
Wheels shall be marked with the following
information:
a) the number of this British Standard,
i. e. BS AU 50- 2. 5c: 1 996

1)

1)

;

Marking BS AU 50- 2. 5c: 1 996 on or in relation to a product represents a manufacturer’s declaration of conformity, i. e. a claim

by or on behalf of the manufacturer that the product meets the requirements of the standard. The accuracy of the claim is solely
the claimant’s responsibility. Such a declaration is not to be confused with third party certification of conformity, which may also

be desirable.

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BS AU 5 0-2.5 c:1 996

b) the country of origin;

The above markings shall be permanent and visible

c) the trademark or other means of identification

when the wheel is fitted with a tyre.

of the manufacturer;
d) the size of the wheel (including offset). In the
case of specific application wheels, including

5 .9 Valve holes
The hole provided in the wheel rim to accommodate

those supplied as original equipment, these shall

the tyre valve shall conform to the dimensions given

be marked with the vehicle manufacturer’s part

in Figure 3 for clamp- in, snap- in or tube valves.

number for the model for which the wheel has

Particular attention shall be paid to the control of

been approved;

depth on counterbores and due note taken that, in

e) the maximum wheel loading as determined by

many standard rim profiles, the counterbore on the

the vehicle or wheel manufacturer;

outer face may come very close to “breaking

f) an indication of the date of production of the
wheel.

through”. In this event, consideration should be
given to increasing the well depth of the rim profile.

Figure 1 — Typical wheels

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BS AU 5 0-2.5c:1 996

Figure 2 — Wheel nomenclature

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BS AU 5 0-2.5 c:1 996

NO TE 1

S ufficient s p ace s hould b e availab le for acces s ib ility to the valve mouth b y hand and b y tyre p res s ure gauge. Additionally,

any s p ecific requirements to p ermit fitment of the intended valve typ e s hould b e agreed b etween the s p ecifier and. the wheel
manufacturer.
NO TE 2

No s harp edges or b urrs are p ermitted at the rim hole.

NO TE 3

All faces to b e p arallel.

NO TE 4

Break all s harp edges .

NO TE 5

Where wheel p rofiles exceed the minimum dimens ions quoted, no counterb oring is neces s ary.

Figure 3 — Valve holes

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BS AU 50-2.5c:1 996

Annex A (normative)
Quality control/test schedule
A.1 Cast material
Light alloys, whether or not included in BS 1 490 or
BS 2970, shall have suitable specified chemical
compositions, mechanical properties and other
physical requirements, which are defined and

A.2.3.2

Tensile test bars taken from wheels

The position of the test bars machined from the

wheels shall be clearly defined on the drawing and
the frequency with which they are to be taken shall
be specified.

A.2.3.3

Micro- structure

Where this is required to be checked, the

agreed between the founder and the wheel

micro- structure and type of etchant shall be agreed

manufacturer with particular attention to age

and the areas and frequency of examination shall be

hardening and stress corrosion.

specified.

A.2 Tests

A.3 Metals other than cast light alloy

A.2.1 General

A.3.1 The metal preferably should conform to an

The following tests are in addition to those specified

appropriate British Standard.

in BS 1 490 and BS 2970; they shall be carried out at

A.3.2 Whether or not a suitable British Standard

a frequency and to a minimum standard of

exists, a detailed specification shall be drawn up to

acceptance agreed between the founder and the

include all relevant data and processing

wheel manufacturer.

instructions which shall be submitted to the wheel

A.2.2 Non-destructive tests
A.2.2.1

Production inspection

Each casting shall be subj ected to either a penetrant
dye inspection for freedom from linear defects or
X- ray examination to ensure conformity to the
radiological standard. Whichever method is used,
there should be cross- checking by the other method

at such frequency as to ensure that the level of
acceptance is maintained.
For composite wheels, appropriate inspection
procedures shall be employed for components and

manufacturer for agreement.

A.3.3 Tests should be as specified by an appropriate
British Standard. If no suitable British Standard
exists, a detailed schedule shall be drawn up. This
schedule shall include not only tests relating to
materials, but also to features of assembly
(e. g. rivets, bolts and nuts, welding).

Annex B (normative)
Validation procedure
B.1 Application groups

their attachments manufactured from materials

Light alloy wheels for passenger cars generally fall

other than light alloys (see also A.3 ).

into two distinct groups, termed “specific

A.2.2.2

Penetrant dye

The type of penetrant dye used and the inspection
procedures shall be specified.
For frequency of testing see A.2.2.1 .

A.2.2.3

Radiological inspection

A radiological standard of acceptance shall be

application” and “general application”. Wheels
supplied as original equipment (OE) are included in
specific application.

B.2 Design validation procedure
B.2.1 Wheels designed for a specific application are
usually to a specification agreed by the vehicle
manufacturer, a maj or item of this specification

established by mutual agreement between the

being the maximum static wheel loading. Wheels

founder and the manufacturer and shall be in the

designed for a general application shall also have a

form of a permanent reference record for each basic

maximum static wheel loading decided by the wheel

design of wheel.

manufacturer.

Inspection to the agreed radiological standard shall

B.2.2 For general application, wheels are usually

be carried out either on X- ray film or by fluoroscopy.

designed so that one basic casting may be used on a

For frequency of testing see A.2.2.1 .

A.2.2.4

Hardness tests

Where hardness tests are required, the frequency of

variety of vehicles. This is generally achieved by
making provision for fixing holes to be drilled on a
variety of pitch circle diameters (PCDs).

testing shall be specified.

A.2.3 Destructive tests
A.2.3.1

Impact test bars taken from wheels

The position of the test bars machined from the
wheels shall be clearly defined on the drawing and
the frequency with which they are to be taken shall
be specified.

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BS AU 50-2.5c:1 996

In addition, certain manufacturers p roduce wheels

It is recommended that the minimum rate of tes ting

made from cas tings having a common b as ic nave

for each of the tes ts describ ed in

and sp ider des ign, b ut the die or p attern equip ment

b asic design p roduced s hould b e one wheel

5.6.4

and for each

is des igned s o that a range of rim widths and/or

p er 1 000 , excep t in the cases of the tes ts des crib ed

offs ets may b e mounted on the nave and s p ider.

in

With this typ e of cas ting it is als o us ual to allow for

should b e one wheel p er 2 5 00 , and in the case of the

5.6.4.3

and

5.6.4.5 ,

where the minimum rate

5.6.4.4 ,

s ome variation of nave thicknes s to facilitate s mall

tes t describ ed in

changes of offs et, and further additional machining

should b e one wheel p er 5 00 0. In no cas e s hall the

may als o b e carried out inside the wheel to ob tain

rate b e less than one wheel p er month.

neces sary clearances .

C.2

B.2.3

out in accordance with

To facilitate a rational ap p roach to the

p rob lems of validating the large numb er of res ultant
p ermutations on this typ e of wheel des ign a s p ecial
validation p rocedure is detailed in

B.3 .

where the minimum rate

S hould failure occur during any one tes t carried

5.6 ,

the p roduction b atch

from which the s amp les were taken s hall b e

quarantined and an inves tigation carried out as to
the cause of failure. If the dimens ional accuracy of

B.3 Special validation procedure for general

the failed wheel is satis factory then the wheel s hall

application wheels

b e s ub j ected to an investigation of mechanical and

B.3.1

metallurgical p rop erties , the caus e of failure
Manufacturers making wheels for general
determined and the b atch re- examined. If the caus e

ap p lication can rationalize the numb ers and typ es of
of failure cannot b e determined, then s ix further
wheel required to b e tested for b oth des ign
wheels shall b e sub j ected to the test which p roduced
validation and routine quality control.
failure. If any one of the six fails , the comp lete b atch
The p rocedure laid down is as follows .

B.3.2

shall b e deemed not to conform to this standard.

D etails of all machining carried out on each

variant of the b as ic cas ting des ign s hall firs t b e
recorded.
Analysis of this data will indicate those wheel typ es
which may b e exp ected to have the minimum
p erformance. Thes e will in general b e wheels having
minimum metal thicknes s in critical areas , b ut

Annex D (normative)
Tyre fitting test. Procedure for the
introduction of new or modified rim
profiles
D.1

A sp ecimen rim incorp orating the new or

modified p rofile s hall b e p rovided for the tyre fitting
could als o b e wheels with greater than the minimum
tes t s p ecified in
thickness b ut having sub s tantial stres s raising
features .

B.3.3

D.2

5.6.4.2 .

Tyres us ed for this test shall b e rep resentative

of thos e p ermitted for the p articular rim s ize,
From this analys is, a wheel tes t p rogramme
s p ecified in BS AU 5 0- 1 . 1 .

s hall b e estab lished b y the wheel manufacturer. The
ob j ect of this p rogramme is to p rove the validity of
the des ign analysis and identify in p ractical terms

D.3

Tyres s hall b e hand fitted using conventional

hand equip ment.

thos e wheel typ es which demons trate minimum

D.4

p erformance lives on the tes t rigs.

the tyre has b een inflated to the recommended

B.3.4

fitting p ress ure.

Up on comp letion of the test p rogramme, thos e

Both tyre b eads s hall b e correctly seated when

wheel typ es to b e us ed for des ign validation and

D.5

routine quality control shall b e estab lis hed b y the

rim without any damage.

wheel manufacturer and details recorded.

D.6

B.3.5

Up on s atis factory comp letion of tes ts on the

The tyre s hall b e deflated and removed from the

After satis factory fitting of all tyres p rovided for

the tes t, the rim p rofile s hall b e p ut forward for

s amp le wheels , the wheel manufacturer shall record

p os s ib le incorp oration into the relevant Part of

a p ermanent reference of the tes t res ults ap p roving

BS AU 5 0 .

all typ es of wheel made from the b as ic cas ting
concerned.

Annex C (normative)
Conformity of production
C.1

Annex E (normative)
Dynamic cornering fatigue test
E.1 Equipment
The tes t machine shall b e one in which a cons tant

In order to verify conformity of p roduction,

wheels s hall b e examined and tes ted in accordance
with

5.6.4 .

rotating b ending moment is ap p lied to a wheel
through the centre memb er, the rotation b eing
ab out the axis of the wheel. The length of the
moment arm s hall b e not greater than 0. 5 m.

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BS AU 50-2.5c:1 996

E.2 Procedure

The load arm and adaptor assembly shall be
attached to the mounting surface of the wheel using
studs and nuts (or bolts) in good condition
representative of those used on the vehicle. The
wheel fixing shall be assembled and manually
tightened at the beginning of the test using the
procedure as specified by the vehicle and/or wheel
manufacturer. The mating surfaces of the test
adaptor and wheel shall be free of excessive build up
of paint, dirt or foreign matter.
E.3 Bending moment determination

The bending moment M (in N · m) shall be
determined using the following equation:
M = F × (È R + d) × 9.81
where
F is the static wheel loading (in kg)
(see B.2.1 );
S is a test factor taken as 1.7;
È
is the coefficient of friction developed
between the tyre and the road and is taken
as 0.75 for the purpose of this test;
d is the offset (in m) (positive for inset wheel,
negative for outset wheel): for specific
application wheels, the actual value shall

be used; for general application wheels,
the applicable value which gives the
maximum value of M shall be used;
R is the theoretical nominal static rolling
radius (in m) of the tyre given by the
following formula:

E.5 Accuracy of applied bending moment

The applied bending moment, as determined by a
suitable means of calibration, shall be accurate to
within ± 5 % of its nominal value throughout both
the rotation cycle and the duration of the test.
Annex F (normative)
Dynamic radial fatigue test
F.1 Equipment

The test machine shall be one with a means to
impart a constant radial force which rotates with
respect to the wheel.
F.2 Procedure

The tyre selected for this wheel test shall be
representative of the tyre specified by the vehicle
manufacturer or an appropriate tyre size for the
wheel. The cold inflation pressure of the test tyre
shall be not greater than 455 kPa.
F.3 Test force determination

The test force Fr (in N) shall be determined using

the following equation:
Fr = F × K × 9.81
where
F is the static wheel loading (in kg)(see B.2.1 );
K is a test factor taken as 2.25.
F.4 Criteria of acceptance

The duration of the test shall be 500 000 cycles with
Fr applied. At completion of the test, there shall be
no evidence of fatigue cracks anywhere on the wheel
as indicated by a penetrant-dye test.
F.5 Accuracy of applied force

where
D1 is the nominal rim diameter (in m);
D2 is the design overall diameter (in m);
FR = 0.78 (or 0.70 for CT tyres).

The applied test force, as determined by a suitable
method of calibration, shall be accurate to
within ± 5 % of its nominal value throughout both
the rotational cycle and the duration of the test.

Annex G (normative)
Impact test
G.1 Equipment

The test machine shall be one in which an impact
force is applied approximately laterally to the rim
E.4 Criteria of acceptance

flange of a wheel complete with tyre. A suitable form
The duration of the test shall be 150 000 cycles with of
falling-weight machine is shown
M applied.
diagrammatically in Figure G.1. Alternatively, the
At completion of the test, there shall be no evidence striker may form the end of a pendulum, provided
of fatigue cracks anywhere on the wheel as
that the arm is of lightweight construction and that
indicated by a penetrant-dye test.
the striker face is horizontal at the moment of
impact with the rim.

8

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BS AU 50-2.5c:1 996

The wheel shall be mounted with its axis at 13° to where
the vertical so that its highest point is presented to
the vertically acting striker. The wheel mount shall
F is the maximum static wheel loading as
be attached to the upper surface at the mid-span of
specified by the vehicle manufacturer
a steel plate of cross section 200 mm × 25 mm
(in kg)(see B.2.1 )
having a span of 700 mm. Each end of the plate shall

G.7 Criteria of acceptance
be supported on two compression type natural
rubber mounts, in parallel, having the following
G.7.1 The wheel shall meet the conditions specified
specification:
in G.7.2 to G.7.5 .
G.7.2 There shall be no visible fractures or cracks
— hardness
50° Shore;
(other than any noted before the test) of the centre
member as indicated by penetrant-dye test.
— diameter
51 mm;
G.7.3 There shall be no separation of the centre
— uncompressed length
27 mm.
member from the rim.
The contact face of the striker shall be 150 mm wide G.7.4 There shall be no sudden total loss of tyre air
and not less than 600 mm long with a 6 mm radius pressure (i.e. the pressure shall be not less
on the long edge which contacts the wheel flange. than 90 kPa, 30 s after impact).
The mass of the wheel mount shall be 20 kg, the
G.7.5 Buckling, cracking or fracture of the rim
height shall be 230 mm and the diameter of the base flange
or general distortion of the wheel shall not, in
shall be 150 mm.
themselves, constitute a failure.
G.2 Calibration of equipment

With the wheel mount located at the mid-span of the
beam, a vertical load of 1 000 kg shall be applied to

the centre of the wheel mount as shown in Figure
G.2 The vertical central deflection of the beam shall
be 7.5 mm. For tolerance see G.8.
G.3 Procedure

The tyre selected for the test shall be either:
a) for wheels specified as original equipment, the
smallest section width size approved by the
vehicle manufacturer; or
b) the smallest nominal section width tubeless
radial-ply size specified for the rim in the edition
of BS AU 50-1.1 current at the date of production
of the wheel (as indicated in accordance
with 5.8 f).
The tyre shall be inflated to a pressure of 180 kPa.
G.4 Dropping height

The dropping height for the striker weight shall
be 230 mm above the highest part of the rim flange
in all cases.

G.8 Accuracy requirements

The accuracy of the mass of the striker, the mass of
wheel mount, and the height of drop shall be
within ± 2 %.
The accuracy of the calibration load (see G.2 ) shall
be within ± 2 % and the specified deflection during
calibration shall be within ± 10 %.
Annex H (normative)

Testing of finishing systems
H.1 Finishing systems

All finishing systems used on wheels shall
withstand the tests specified in H.2.1 , H.2.2 and
H.2.3 . These may be carried out on a test panel
(minimum size 150 mm × 100 mm) of the same
material and surface finish as used for the wheel,
except for the salt spray test (see H.2.1 ), for which it
is essential that the test is carried out on a finished
wheel.
H.2 Tests
H.2.1

Salt spray test

This test shall be carried out in accordance with
The striker shall be generally over the tyre and the BS AU 148-2:1969 to condition T 35 for a minimum
duration of 96 h, after which there shall be no
radiused edge shall overlap the rim flange
evidence of corrosion visible to the naked eye, with
by 25 mm.
the exception of highly polished surfaces where
G.6 Mass of striker
superficial corrosion shall be acceptable. The
The mass D (in kg) of the striker shall be
scratch test damage specified in 4.2.4 of
determined using the following equation:
BS AU 148-2:1969 need not be applied to the highly
D = 0.6F + 180

polished surfaces.
G.5 Alignment of striker

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9


BS AU 5 0-2.5c:1 996

Figure G.1 — Wheel impact machine

10
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BS AU 50-2.5c:1 996

Figure G.2 — Machine calibration method
H.2.2

Flexibility and adhesion

This test shall be carried out in accordance with
BS AU 1 48- 3: 1 969 to groups 2 and 3. On completion
of the test, there shall be no evidence of paint lifting.

H.2.3

Resistance to chipping

This test shall be carried out in accordance with
BS AU 1 48- 1 5: 1 969.
The minimum acceptance level shall be in

Annex J (informative)
Guidance on certain aspects of the
design of wheel attachment systems
J.1 Type of fixing
Although other forms of attachment may constitute
good design practice and be acceptable, these
recommendations are limited to multiple nut or bolt
attachments having spherical or conical bearing

accordance with clause 5 , assessment 2 (slight) of

and locating surfaces, or a flat bearing surface with

that standard.

parallel shank location.

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11

BS AU 5 0-2.5c:1 996

The transition between the threaded and
unthreaded
portions of a bolt shank or stud should
Although both centrally spigotted mountings and
non-spigotted mountings are allowed for, the former be designed to reduce stress concentrations.
is preferred.
J.3.3 Undercuts should have a 3 mm minimum
radius
at the root.
J.3 Thread data
J.3.1 Threads should be selected from:
J.2 Mounting

UNF
UNF
metric
metric

12

class 2B
(internal)
class 2a
(external)
ISO 6H
(internal)
ISO 6g

(external)

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J.3.2






See BS 1580-1 &
BS 1580-2
See BS 3643-2




© BSI 07-1999


BS AU 5 0-2.5 c:1 996

List of references

(see clause 5.2 )

Normative references

BSI publications

BRITISH STANDARDS INSTITUTION, London

BS 1490:1988,

Specification for aluminium and aluminium alloy ingots and castings for general
engineering purposes.

BS 2970:1989, Specification for magnesium and magnesium alloy ingots and castings.
BS AU 50, Tyres and wheels.
BS AU 50-1, Tyres.
BS AU 50-1.0:1977, General.
BS AU 50-1.1:1977, Car tyres.
BS AU 50-1.1.1:1992, Specification for sizes, loads and inflation pressures.
BS AU 50-2, Wheels and rims.
BS AU 50-2.0:1979, General (including terms and definitions, and construction and workmanship).
BS AU 50-4, Rim profiles and dimensions.
BS AU 50-4.1, Car rims.
BS AU 148, Methods of test for motor vehicle paints.
BS AU 148-2:1969, Resistance to continuous salt spray.
BS AU 148-3:1969, Flexibility and adhesion.
BS AU 148-15:1969, Resistance to chipping.
Informative references

BSI publications

BRITISH STANDARDS INSTITUTION, London

BS 1580, Specification for unified screw threads.
BS 1580-1:1962 & BS 1580-2:1962, Diameters ¼ in and larger.

BS 3643, ISO metric screw threads.
BS 3643-2:1981, Specification for selected limits of size.
BS AU 50, Tyres and wheels.
BS AU 50-2, Wheels and rims.
BS AU 50-2.6:1983, Specification for road wheels manufactured wholly or partly of light alloy for mopeds
and motor cycles.

© BSI 07-1999
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BS AU
5 0-2.5 c:1 996

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