BRITISH STANDARD AUTOMOBILE SERIES
1

BSAU50:

m 4 :

Subsection 7 . 1

a

1991
I S 0 5995-2

Tyres and wheels

1 988
TW-

6H

1 6 pages

Part 4. Rim profiles and dimensions
Section 7. Moped rims

Subsection 7 . 1 S pecification for moped

rims

e

O

a
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BSI BS*AU*SO: PT4
BS AU

: S UBS E C* 7 * L 91

L b 2 4 b b 9 0 2 7 L9 Y9 8

50 : Part 4 : Subsection 7 . 1 : 1991
National foreword

AU 50, prepared under the direction of the
Automobile Standards Policy Committee, is identical with IS0 5996-2 1988
‘Moped tyres and rims - Part 2 Rims’, published by the International
Organization for Standardization (ISO). The corresponding tyre details are dealt
with in Part 1 (Subsection 7. i). Other Parts of the standard are:
Part 1 Tyres
Part 2 Wheels and rims
Part3 Valves
Part 4 of BS AU 50 (covering rim profiles and dimensions) has been introduced to

assist cross-referencing between tyre specifications and the corresponding
specifications. Subsections of Part 4 will partially supersede the information
contained in BS AU 50 Part 2 Section lb 1980 which has been amended
accordingly.
This Subsection of this Part of BS

:

:

ri m

:

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Cross-references
Internationalstandard

Corresponding B ritish Standard

BS AU 50 Tyres and wheels
Part 1 Tyres
Section 7 Moped tyres
IS0 5995-1 1982
Subsection 7.1 1989 Specification for tyre designations,
dimensions and load ratings
(Identical)

Part 4 Rim profiles and dimensions
Section 6 Motorcycle
IS0 6054-2 1990
Subsection 6.3 1991 Specification for code designated
series (diameter codes 4 to 12) rims
(Identical)
The %chnical Committee has reviewed the provisions of IS0 3911 and
IS0 4249-3, to which reference is made in the text, and has decided that they are
acceptable for use in conjunction With this standard.
:

:

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ri m s

Compliance with a British Standard does not of itself confer immunity from
legal obligations.


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:SUBSEC*7.3

B S AU

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Part 4

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: Subsection 7 . 1 : 1991

Contents


Page
Inside front cover
Back page

National foreword
Committees responsible
Specification

1
2
3
4

6

6

e

7

Scope
Normative references
General
Designation and marking
Rimcontours
Rimdiameters
Permitted rim widths

1


Annexes

A

B

Permitted rim width codes for tyres used on mopeds and small cubic
capacity motorcycles designed for a maximum speed of 100 km/h
Methods for measuring and gauging moped dimensions
ri m

4
5

ables

1
2

3
A. 1
B. 1

Dimensions of tapered bead seat
(straight side)
Specified diameters and measuring diameters
Permitted rim width codes (moped tyres)
Permitted rim width codes
%De widths for moped rims

rims

ri m

ri m

2

3
3

4
7

Figures
1
B . l
B.2
B.3
B.4

B.5
B.6
B.7
B. 8
B.9

B . 10
B. 11
B. 12


(straight side)
Contour of tapered bead seat
Rim dimensions
Rim measurement
?ape details
?ape mandrel
Vernier gauge
mm graduation)
Vernier gauge details for measuring principle for flange height, G
Use of vernier with spacer
Measuring principle of dimension L1
Calliper vernier for measuring dimension LI
Measuring principle of bead seat angle B
'Ibo1 for measuring angle
Calliper vernier for measuring widths
ri m s

(1 /20

ß

rim

2
5

6
6
7


7
8

8
9

9
9

9
10

1


~

I S 0 5995-2 : 1 988 (E)

I N TERNATI ON AL STANDARD

M o p e d Lyres an d ri m s

-

Part 2 :
Rims

O

1

3

Scope

Ti-,,- part of

I

5995

saecifies L. .e dimensions of taaereec -ea(

General

3. 1

R i m con tou r

seat ri m s (strai gh t s i d e i f o r m oped tyres. I t applies t o th ose ri m
contou r dimensions necessary fo r tyre m oun ti ng an d fi tti n g of
th e tyre t o th e rim, terms fo r wh i ch are used i n accordance w i t h

IS0

Th e ri m o n th e side of th e tyre shall have a sm ooth contou r free
of sharp edges,

391 1 .

3. 2

Annex A provi des details o n perm i tted ri m wi d th codes fo r
tyres used o n mopeds an d small cu bi c capaci ty m otorcycl es
designed fo r a m axi m u m speed of 1 00 km /h . Ann ex B presents
m eth ods fo r measuring an d gau gi ng dimensions of tapered
bead seat ri m s fo r mopeds.

NOTE - Tyre designation, dimensions an d l oad rati n g s are g i ven i n

I S 0 5995-1 .

R i m va l ve h o l e

Th e ri m valve h ol e shall be centred o n th e bo tto m of th e ri m
wel l .

On

th e

tyre

side,

th e

edges

chamfered, wh i l e on the h u b side,


shall

be

rou nded

or

th e edges shall be free of

bu rrs wh i ch cou l d damage th e valve.

3. 3

D efi n i ti o n of

H1 a n d L 1

Hl represents th e u n obstru cted depth above th e ri m base, wi t h

th e ri m tape fiftted t o perm i t fi tti n g of th e tyre.
L I represents th e wel l wi d th above th e ri m tape.

2

N orm ati ve references

4
The fol l owi n g


standards con tai n

reference i n th i s text,

IS0

5995.

consti tu te

provi si ons which,
provi si ons of

A t th e ti m e of pu bl i cati on,

th i s

Desi g nati on an d m arki n g

th rou g h
part

of

th e edi ti on s i n di cated

Th e ri rn shall be designated by i ts nom i n al diameter code and
n om i n al wi d th (for example


18

x

30, 5) .

were valid. Al l standards are su bj ect t o revision, and parties t o
agreements based on th i s part of

IS0

5995

are encouraged t o

i nvesti gate th e possi bi l i ty of appl yi ng th e m ost recen t edi ti ons
of th e standards l i sted bel ow. Members of IEC and

IS0

m ai n-

tai n registers of cu rrentl y val i d I n tern ati onal Standards.

I S 0 391 1 : 19n, Wheels/rims - Nomenclature, designation,
marking and units of measurement.

IS0 4249-3: 1986, Motorcycle tyres and rims (Code-designated
series) - Parì3: Rims.
IS0


5995-1 : 1982, Moped tyres and rims - Part I : Tyres.

Motorcycle tyres and rims (diameter codes 4
to 12) - scooter type - ~ art. 2:Rims.
I S 0 6054-2: 1 986,

5

Rim contou rs

Dimensions an d tolerances of tapered bead seat ri m s are gi ven
i n tabl e 1 .

6

Ri m di ameters

N om i n al

ri m

diameter codes,

speci fi ed

ri m

diameters


and

measuring ri rn diameters are gi ven in tabl e 2.

7

Perm i tted ri m wi d th s

Th e perm i tted ri m wi d th codes fo r m oped tyres are gi ven i n
tabl e 3.

1


B

I S 0 5995-2

:

S

I

B S * AU * S O: P T4

: SU BS E C *7. 3

m


9 3

3 6 2 4 b b 9

m

!I

0 2 7 3 9 5 2

1 988 ( E )

A

4
-

I

Figure 1

Tabl e 1

-

Contou r of tapered bead seat rims (strai g h t side)

-

Di men si ons of tapered bead seat rims (strai g h t side)

D i m en si on s

G

Nominal ri m

A

wi d th cod e

_

1 )

2)

_

_

30,5

30,5

8

3,5

34


34

38

38

_

min.

R2

R4

R 3

3,5

3, 5

4,5

1 0

1 0, 5

5

min.


1 4

2,5

1 4

2,5

rn i n .

m ax.

1

2,s

1

2

3

4,5

1 6

4,5

1 ,5


3

5

1 6

7

1

3,5

3

~~

d i am eters

Di m en si on H
I

L1

min.

rn i n .

3, 5

s ati s facto ry f i t t i n g


2

1

7.5

_

o b j e cti ve .

-

27

For r i m

H11 1 2 1

m i l l i m e tre s

+ 0,5

+ 1

n

_

P


i n

in

of

l ess th an

or

co n j u n cti o n

th e

tyre.

Th e

eq u al

wi th

to

400

mm,

i n crease th e


d i m e n s i o n L.1

actu al wel l

d e p th

d efi n es

of

th e

th e

d e p th

HI,

,
,
,
i
n

u n o b s tru cte d

r i m sh al l

by


1

mm.

space

be d e te rm i n e d at

above

th e

ri m

th e

n i ppl e

heads,

wi th

th e

m an u factu re r' s d i s cre ti o n i n

tape

fi tte d


ord er t o

to

pe rm i t

ach i eve th i s


T

0273953

IS0

Tabl e 2 -

5995-2 1 988 (E )

Speci fi ed ri m di ameters an d measu ri ng ri m
d i ameters
Dimensions i n m i l l i m etres

Speci fi ed ri m

M easu ri n g ri m

d i am eter


d i am eter’ )

14

357.47

357,l

15

382.87

382, 5

16

405.97

405,6

17

433, 67

433, 3

18

459.07


458, 7

19

484, 47

484.1

21

535.27

534.9

N om i n al ri m

I

d i am eter code

1)

Tolerance

on

I

th e


D

measured

bead

seat

I

ci rcu m feren ce
mm.

( E x m easu ri n g ri m d i am eter) of th e r i m is

Tabl e 3 - Permi tted ri m wi d th codes (moped tyres)
N om i n al secti on wi d th

N om i n al ri m
d i am eter code

Cyl i n d ri cal

Code

seat ri m s

WM ri m s1 )

1

2

31 4

114

27 - 30, 5
-

34

27 - 30, 5

-

34

30, 5

2

34

3/4

1.20

27 - 30.5

2 112


3

38

-

-

34

-

38

38

Di vi d ed rims21

< 10

2

3
1)

See

IS0


4249-3fo r

detail s.

2)

See I S 0

6054-2fo r

detail s.

3)

M T con tou r.

wi d th codes

Tapered bead

2
> 12

Perm i tted ri r

SN

112

-


38

1.20

-

1.35

1. 20

-

1.35

-

1. 20

-

1.35

-

1. 50

-

1.60


1.35

-

1.50

-

1. 60

-

185

1.50

-

1.60

-

1.85

1. 50

Drop-cen tre rims21

1.50


-

1.75

1. 503)

1. 75

-

2.10

1. 853) - 2. 153)

-

1. 853)
-

2. 50

-

2. 3


BSI
IS0 5 s - 2


:

I 988

BS*AU *SO: PT4

: SU BSEC*7-3

9 3

W

3 b 2 4 b b 9

0 2 7 3 9 5 4

3

W

(EI

An n ex A
ti ve)

( i n fo rm a

Perm i tted ri m wi d t h cod es for tyres u sed on mopeds an d sm al l cu bi c
capaci ty m otorcycl es d esi g n ed for a m axi m u m speed of 1 00 k m / h


N OTE

-

I S 0 5995-1

g i ves

further information on moped

tyres.

N om i n al section
wi d t h

SN

Perm i tted ri m wi d t h codes

-

Cyl i ndri cal ri m s

Cod e

2
2 114
2 112
2 31 4
3

3 il4

1 .20

-

1 . 35

1 . 20

-

1 . 35

-

1 .50

-

1 . 60

1 . 35

-

1 .50

-


1 . 60

-

1 . 85

1 -50

-

1 .60

-

1 . 85

1 . 60

-

1 . 85

-

1 . 85')

-

2. 1 5')


2. 1 5


BS I BS* AU* SO: PT4

: S UBS E C * 7 - L 7 3

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I S 0 5995-2 : 1 988

~

(E)

An n ex B

(i n form ati ve)

M eth o d s for m easu ri n g an d g au g i n g m oped ri m d i m en si on s

B.l


B. 2

Scope

This annex defines methods of measuring and gau g i ng dimen-

Ri m dimension m easu rem en ts

B . 2. 1

G en era l

sions of tapered bead ri m s fo r mopeds.
Al l measurements sh al l be made on rims ready for tyre m ou n tStandardi zati on of ri m dimensions applies on l y to those con -

i n g and placed on fl at surfaces. For accurate measurements,

tou r dimensions necessary for tyre m ou n ti n g and th e fi tm e n t of

gauge and tapes shall always be set perpendicular to th e ri m

th e tyre to th e ri m .

flanges on bo th bead seats.

B.2.2

M a i n r i m d i m e n s i o n s t o be m e a s u re d

an d g au g ed


The main ri m dimensions wh i ch shall be measured and gauged
are i n di cated i n fi g u re B . 1 .

A

4

c

t
Q

A

Speci fi ed ri m wi d th

L.1

Wel l wi d th above ri m tape

(al

Ci rcu m feren ce measuring po i n t o n th e tyre bead seat = 1 .5 mm

Bead se atwi d th

D

p


Speci fi ed ri m diameter

Rg

Flange rad i u s

R3

Bead seat radius

D1
G

Hi

M easu ri n g ri m diameter
Flange h ei g h t
U n obstru cted deoth above ri rn base wi th ri rn taoe fi tte d t o oerm i t
tyre fi tm e n t

Fi g u re B . l

-

R4

B

radius top


Bead seat angle

Ri m di m en si on s

5


BSI
IS0

5995-2

B. 3

:

: S UBS E C* 7 - 3 9 3

BS*AU *50: PT4

and bead seat ci rcu mferen ce

Ch eck ( g au g e ) th e

pl ate,

wi th

tape o n th e appro pri ate m an d rel an d su rface


t h e tape fl at.

bead seats eq u al l y,

Fi rst m eth od

Th e

th e

Th e

ri m

m easu rem en t

cu m feren ce

i l l u s trate d

co rre ct

m arked

rel ated

i n fi g u re

tape


fo r

wi th

d i am eter.

Th e

to

8. 3

th e

d etai l s

is

is

ri m

of

made

aro u n d

m an d rel


used,

to

ri m

stan d ard

A

ci rcu m feren ce.

care

be

a

be i n g taken

m easu red .

wi d t h

co d e

referen ce tem pe ratu re sh al l

Th e


an d

be 20

to

l evel

tape

tape

sh al l

n o m i n al

s trai g h t

of

en d

Th e tape sh al l

Tape

th e

wi d th s


tape

sh al l

sh al l

c o n t ac t th e

co n tact

th e

o th e r en d

Tape

L

B. 1 .

wi t h i n

as

be

ri m

'T.


l en g th ,

bo th

n o tch .

I t i s recom m en d ed th at,

t wo

h ol d i n g

on

-

perso n s

th e

th e

are

tape

ends,

th e


except f o r

n eed ed

po s i ti o n

o th e r

to

experi en ced ri m

m ake

th e

an d appl yi n g

taki n g

th e

i n specto rs,

m easu rem en t

n o t m o re th an

-


50

N

on e

pu l l

read i n g s.

Rim measurement

D i m en si on s

4

ri m o n

be i n d i cate d i n tabl e

ci r-

ch o ose th e

Figure 8 . 2

,

I


Figure 6. 3 - Tape detai l s

6

W

1 988 ( E )

Meth od s of measuring specified di ameter

B. 3.1

3 6 2 4 bb9 0 2 7 3 9 5 6 5

=

i n

m i l l i m e tre s

I

I


IS0 5995-2 1 1988 (E)

O


Table B.l - Tape widths for moped rims

rect protusion is used (1,5 rnrn for moped rims). Calculate the
averages of the two flange heights GAand GB(seefigure
Calculate the measured circumferences ü 1 A and
by the
following equations:
U1 A = UOA -2 n GA

Dimensions in millimetres

B.6).

u, ,

35

B.3.2 Second method

Measure the circumference of the upper part of both flanges by
means of an inextensible steel tape-line (10 rnm width, and
0,3 mm thickness with 0,5 mm graduations) taking care that it
contacts the rim. Record the two measurements UoAand Uos.
Using an appropriate vernier gauge, as illustrated in figure 6.5,
measure the height of both flanges in at least four points equally spaced around the circumference, taking care that the cor-

= UOB -2 R GB
NOTE - When rims have a difference of more than 2 mm between the
two outer circumferences U,, and Uoa,the vernier gauge should be
appropriately applied and a spacer with a thickness, catering for the

difference in circumference
t,

I =

I

-

%A

2 n

1

should be interposed between the top of the shorter flange and the vernier gauge (see figure 8.7).
Dimensions in millimetres

1 ) Surface roughness value at the discretion the person checking.
NOTE - Tolerance on D, measurement is

-8,%

of

Figure

B.4

- Tape mandrel

Dimensions in millimetres

I+
Figure B.5 - Vernier gauge (1/20 mm graduation)


BSI BS*AU*SO: PT4

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Di m en si on s i n m i l l i m etres

Fi gu re B . 6

-

Vern i er g aug e d etai l s f o r measu ri ng pri n ci pl e f o r fl an g e h ei g h t, G

O

Spacer

Fi gu re 8 . 7


-

Use

of

verni er wi t h spacer

a

8


o

B. 3. 3

Wel l

wi d th a b o v e ri m t a p e ,

The wel l wi d th above th e ri m tape,
sh own i n fi g u re

L I ,

L I

shall be measured i n accordance wi th th e pri nci pl e demonstrated i n fi g u re


B.8

and th e to o l

B. 9.

LI

P

L
Figure B . 8

8. 3. 4

-

M easu ri n g pri n ci pl e o f di mensi on

B ea d seat

an g l e,

LI

Fi gu re B . 9

-

I


Call i per verni er for measu ring di mensi on

L ,

p

The bead seat angle, ß, shall be measured i n accordance wi th th e pri n ci pl e dem onstrated i n fi g u re B.1 0 and th e to o l sh own i n fi g u re
B . l l . (See also th e note i n 8. 3. 2.)

Di m ensi on s

Figure

an g l e

ß

Fi gu re B . l l

-

in

mi l l i metres

Tool for m easu ri n g an g l e

ß



BSI BS*AU*50: PT4
IS0

: SUBSEC*?. L

91

œ

Lb2 Ybb9

7

5995-2 : 1988 ( E )

B.3.5

8. 3. 5. 1

Oth er ri m d i m en si on s

R i m wi d th

Th e ri m wi d th at th e bead seat,

A l,

and th e speci fi ed ri m wi dth ,


A ,

sh ou l d be measured wi t h a calliper vernier (see fi gu re B . 1 2) .

Fi g u re 8. 1 2 - C al l i pe r ve rn i e r f o r m e as u ri n g r i m w i d t h s

B. 3. 5. 2

R i m i n specti o n

To gauge (ch eck) flange h ei gh t and wel l depth, a vernier gauge as sh own i n fi gu re B. 6 sh ou l d be used.

10

027L9b0

œ


'

-

B S I B S * AU* 5 0 : P T 4

: S UBS E C* 7 . L

9L

m


Lb 2 4 b b 9

B S AU 50

Publication(s) referred to

See

national foreword.

027L9bL 9
_ _ _

:

Part 4

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Subsection 7 . 1

:

1991



B S I

50

BS AU

BS*AU *SO: PT4

:SUBSEC*7.1

91

W

162 4 669

0271 962

O M ’

-T

:

Part4 :

I

I


Subsection 7 . 1 :

C ommittees res p o ns ib le for this

1991

IS 0

5995-2

:

B ritis h S tandard

1988

The preparation of this British Standard was entrusted by the Automobile
Standards Policy Committee (AUE/-) to Echnical Committee AUE/4, upon
which the following bodies were represented:
Agricultural Engineers’ Association
Automobile Association
British Industrial Truck Association
British Pressure Gauge Manufacturers’ Association
British Rubber Manufactureis’ Association
Bus and Coach Council
Department of Transport
Reight Transport Association
Institute of Road Transport Engineers (Incorporated)
Motor Cycle Industry’ s Association of Great Britain Ltd.

Motor Industry Research Association
National Tyre Distributors’ Association
Retread Manufacturers’ Association
Road Haulage Association Ltd.
Royal Automobile Club
Society of Motor Manufacturers and Traders Ltd.

This British Standard, having

been prepared under the
direction of the Automobile
S tandards Policy Committee,
was published under the
authority of the Standards
Board and comes into effect on
31 January 1 992

A mendments i s s u e d s i n c e p u b l icatio n

Amd. No.

Date

Tkxt affected

O BSI 1 991
The foliowing BSI references
relate to the work o n this
standard:
Committee reference AUE/4

Draft for comment 86/77796 DC
ISB N

O 580

20373

9201 -5-0.8k-B

5

B S I, 2

Park Street,

TW- 6H- 1 6

London W l A 2B S

B S I, Linford W o o d , M i l t o n

Keynes

MK14

6LE

AUE/$