Cycles — Safety requirements for bicycles — Part 4: Braking test methods

This document specifies the braking test methods for ISO 4210‑2.

Cycles — Exigences de sécurité pour les bicyclettes — Partie 4: Méthodes d'essai de freinage

General Information

Status
Published
Publication Date
10-Jan-2023
Current Stage
6060 - International Standard published
Due Date
12-Sep-2022
Completion Date
11-Jan-2023
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INTERNATIONAL ISO
STANDARD 4210-4
Second edition
2023-01
Cycles — Safety requirements for
bicycles —
Part 4:
Braking test methods
Cycles — Exigences de sécurité pour les bicyclettes —
Partie 4: Méthodes d'essai de freinage
Reference number
ISO 4210-4:2023(E)
© ISO 2023
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ISO 4210-4:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
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Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2023 – All rights reserved
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ISO 4210-4:2023(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Test methods ............................................................................................................................................................................................................ 1

4.1 Brake lever grip dimensions ...................................................................................................................................................... 1

4.1.1 Test method for the brake lever similar to type A or type B ....................................................... 1

4.1.2 Test method for the brake lever similar to type C ................................................................................ 3

4.2 Brake levers — Position of applied force ........................................................................................................................ 5

4.2.1 Type A and B brake levers .......................................................................................................................................... 5

4.2.2 Type C brake levers .......................................................................................................................................................... 5

4.3 Brake-block and brake-pad assemblies — Security test .................................................................................. 6

4.4 Hand-operated braking-system — Strength test .................................................................................................... 6

4.5 Back-pedal braking system — Strength test ............................................................................................................... 7

4.6 Braking performance ....................................................................................................................................................................... 7

4.6.1 Test bicycle .............................................................................................................................................................................. 7

4.6.2 Secondary brake levers ................................................................................................................................................ 7

4.6.3 Track test method .............................................................................................................................................................. 8

4.6.4 Back-pedal brake linearity test .......................................................................................................................... 17

4.6.5 Machine test method ................................................................................................................................................... 17

4.7 Brakes — Heat-resistance test ..............................................................................................................................................23

4.7.1 Drag test ..................................................................................................................................................................................23

4.7.2 Brake performance measurement after drag test ................................... .......................................... 24

Annex A (informative) Explanation of the method of least squares for obtaining the line of

best fit and ±20 % limit lines for braking performance linearity ...............................................................26

Annex B (informative) Method of measuring braking distance with different lever forces ................29

Annex C (informative) How to derive the total braking energy for brake heat resistance test ........31

iii
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ISO 4210-4:2023(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 149, Cycles, Subcommittee SC 1, Cycles

and major sub-assemblies, in collaboration with the European Committee for Standardization (CEN)

Technical Committee CEN/TC 333, Cycles, in accordance with the Agreement on technical cooperation

between ISO and CEN (Vienna Agreement).

This second edition cancels and replaces the first edition (ISO 4210-4:2014), which has been technically

revised.
The main changes are as follows:
— improvement of 4.1.2;
— addition of test temperature requirement in 4.6.3 and 4.6.5;
— change in the method of calculating the braking distance in 4.6.3;
— addition of rolling resistance requirement and cooling requirement in 4.6.5.7;
— change in the test method to no cooling air of 4.7;
— addition of Annex B and Annex C.
A list of all parts in the ISO 4210 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
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ISO 4210-4:2023(E)
Introduction

This document has been developed in response to the demand throughout the world. The aim is to

ensure that bicycles manufactured in conformity with this document will be as safe as is practically

possible. The tests are designed to ensure the strength and durability of individual parts as well as of

the bicycle as a whole, demanding high quality throughout and consideration of safety aspects from the

design stage onwards.

The scope is limited to safety considerations and has specifically avoided standardization of

components.
If the bicycle should be used on public roads, national regulations apply.
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INTERNATIONAL STANDARD ISO 4210-4:2023(E)
Cycles — Safety requirements for bicycles —
Part 4:
Braking test methods
1 Scope
This document specifies the braking test methods for ISO 4210-2.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 4210-1, Cycles — Safety requirements for bicycles — Part 1: Vocabulary

ISO 4210-2:2023, Cycles — Safety requirements for bicycles — Part 2: Requirements for city and trekking,

young adult, mountain and racing bicycles
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 4210-1 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Test methods
4.1 Brake lever grip dimensions
4.1.1 Test method for the brake lever similar to type A or type B

Fit the gauge illustrated in Figure 1 over the handlebar grip or the handlebar (when the manufacturer

does not fit a grip) and the brake lever as shown in Figure 2 so that face A is in contact with the handlebar

or grip and the side of the brake lever. Ensure that face B spans an area of that part of the brake lever

which is intended for contact with the rider's fingers without the gauge causing any movement of the

brake lever towards the handlebar or grip. Measure the distance, a, the distance between the last part

of the lever intended for contact with the rider's fingers and the end of the lever. The measurement

should be conducted only on a fully assembled bicycle.
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ISO 4210-4:2023(E)
Dimensions in millimetres
Key
A face A
B face B
C rod
D 75 mm or 90 mm
Figure 1 — Brake lever grip dimension gauge for type A and type B
a) Type A
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ISO 4210-4:2023(E)
b) Type B
Key

a distance between the last part of the lever intended for contact with the rider's fingers and the end of the lever

Figure 2 — Method of fitting the gauge to the brake lever and handlebar
4.1.2 Test method for the brake lever similar to type C

Fit the gauge illustrated in Figure 3 over the handlebar and brake lever as shown in Figure 4 so that face

A is in contact with the handlebar or handlebar grip and the brake lever. Put the face of cylinder B in

contact with the part of the grip intended for contact with the rider’s hand and check if the requirements

are met. In the case of brake lever with position adjustment, check if the requirements are met in a

specific range of the adjustable range.
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ISO 4210-4:2023(E)
Dimensions in millimetres
Key
A face A
B face of cylinder
C rod
Figure 3 — Brake lever grip-dimension gauge for type C

Figure 4 — Method of fitting the gauge to the brake lever and handlebar for type C

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ISO 4210-4:2023(E)
4.2 Brake levers — Position of applied force
4.2.1 Type A and B brake levers

For the purposes of braking tests in this document, for brake levers similar to type A or type B, the

test force shall be applied at a distance b, which is equal to either dimension a [see ISO 4210-2:2023,

Figure 1 a) and b)] as determined in 4.1.1 or 25 mm from the free end of the brake lever, whichever is

the greater [see Figure 5 a) and Figure 5 b)].
4.2.2 Type C brake levers

For the purposes of braking tests in this document, for brake levers similar to type C, the test force shall

be applied at a distance of 25 mm from the free end of the brake lever [see Figure 5 c)].

Dimensions in millimetres
a) Type A b) Type B
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ISO 4210-4:2023(E)
c) Type C
Key
F applied force
b ≥25 mm
Figure 5 — Position of applied force on the brake lever
4.3 Brake-block and brake-pad assemblies — Security test

Conduct the test on a fully assembled bicycle with the brakes adjusted to a correct position with a rider

or equivalent mass on the saddle. The combined mass of the bicycle and rider (or equivalent mass) shall

be 100 kg.

Actuate each brake lever with a force of 180 N applied at the point specified in Figure 5 or a force

sufficient to bring the brake lever into contact with the handlebar grip, whichever is lesser. Maintain

this force while subjecting the bicycle to five forward and five rearward movements, each of which is

not less than 75 mm distance.

Then conduct the test described in 4.4 or 4.5 as appropriate, depending on the style of brake, and then

the test described in 4.6.
4.4 Hand-operated braking-system — Strength test

Conduct the test on a fully assembled bicycle. After it has been ensured that the braking system is

adjusted according to the recommendations in the manufacturer's instructions, apply a force to the

brake lever at the point specified in Figure 5. This force shall be 450 N, or such lesser force as is required

to bring

a) a brake lever into contact with the handlebar grip or the handlebar where the manufacturer does

not fit a grip,

b) a brake extension lever level with the surface of the handlebar or in contact with the handlebar,

and
c) a secondary brake lever to the end of its travel.
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ISO 4210-4:2023(E)

Repeat the test 10 times on each brake lever, secondary brake lever, or extension lever.

4.5 Back-pedal braking system — Strength test

Conduct the test on a fully assembled bicycle. After it has been ensured that the braking system is

correctly adjusted, and with the pedal cranks in a horizontal position, as shown in Figure 6, apply a

vertically downward force to the centre of the left-hand pedal spindle. Increase the force progressively

to 1 500 N and maintain fully for 1 min.
Key
1 chain
2 hub sprocket
3 non-drive side crank
4 chain wheel and pedal crank
5 point of force application
6 pedal

F vertically downward force to the centre of the left-hand pedal spindle, 1 500 N

Figure 6 — Back-pedal brake test
4.6 Braking performance
4.6.1 Test bicycle

Conduct the braking performance test on a fully assembled bicycle after the brakes have been

subjected to the strength test detailed in ISO 4210-2:2023, 4.6.6, and 4.6.7. Before testing the bicycle

by either method, inflate the tyres and adjust the brakes to the nominal reach position according to the

manufacturer's instructions. In the case of rim-brakes, adjust it to the maximum clearance specified by

the manufacturer.
4.6.2 Secondary brake levers

Where a bicycle is fitted with secondary brake levers attached to brake levers, bar-ends, or aerodynamic

extensions, separate tests shall be conducted for the operation of the secondary brake levers in addition

to tests with the normal levers.
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ISO 4210-4:2023(E)
4.6.3 Track test method
4.6.3.1 Test track

a) Use an indoor test track if possible. If an outdoor test track is used, pay special attention to ambient

conditions throughout the test. The ambient temperature while performing the test shall be

20 °C ±10 °C.

b) The gradient of the track shall not exceed 0,5 %. If the gradient is less than 0,2 % carry out all runs

in the same direction. If the gradient lies between 0,2 % and 0,5 %, carry out alternate runs in

opposite directions.

c) The surface shall be hard, of concrete or fine asphalt, and free from loose dirt or gravel. The

minimum coefficient of friction between the dry surface and the bicycle tyre shall be 0,75.

d) The track shall be essentially dry at the commencement of tests. When testing in accordance with

the requirements of 4.6.3.6, the track shall remain dry throughout the tests.
e) The wind speed on the track shall not exceed 3 m/s during the tests.
4.6.3.2 Instrumentation

The test bicycle or the test track shall be instrumented to include the following:

a) a calibrated speedometer or tachometer (accurate to within ±5 %) to indicate to the rider the

approximate speed at the commencement of braking;

b) a velocity-recording device (accurate to within ±2 %) to record the velocity at the commencement

of braking;

c) a distance recording system (accurate to within ±1 %) to record the braking distance;

The velocity-recording device and distance recording system should have the least possible resistance

to the road surface.

d) a water spray system, to provide wetting of the braking surface, consisting of a water reservoir

connected by tubing to a pair of nozzles at the front wheel and a pair of nozzles at the rear wheel.

A quick-acting on/off valve shall be included for control by the rider. Each nozzle shall provide a

flow of water at ambient temperature of not less than 4 ml/s. Details of the positions and directions

of nozzles for rim brakes, hub brakes, band brakes, disc brakes, and back-pedal brake are given in

Figures 7 to 13;

NOTE Figures 7 and 8 for rim brakes show side-pull callipers but the same arrangements apply to

centre-pull callipers and cantilever brakes.

e) a brake-actuation indicating system to record independently when each lever or pedal is actuated.

4.6.3.3 Mass of bicycle, rider, and instrumentation

The combined mass of the bicycle, the rider, and the instrumentation shall be 100 kg.

When wet condition braking tests are performed, the combined mass can decrease throughout the test

due to water consumption, but it shall not be less than 99 kg at the end of the valid test runs.

Where a manufacturer specifies that their bicycle can carry a mass such that the sum of that mass plus

the mass of the bicycle is in excess of 100 kg (60 kg for young adults) to some value M, apply M as total

mass.

Any extra mass shall be positioned above the rear wheel and in front of the rear axle.

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ISO 4210-4:2023(E)
4.6.3.4 Force applied to the brake levers
a) Magnitude and position of force on brake levers

Apply a handgrip force not exceeding 180 N at the point as specified in Figure 5. Check before and

after each series of test runs to verify the lever force. In order to stabilize the lever operating force

during braking, the lever may be fitted with an attachment which limits its range of movement. Brakes

that produce high braking forces with small operating forces should have their brake characteristics

checked beforehand to ensure that they can be tested safely.

NOTE When the braking distance can only be measured at lower lever operating force, see Annex B for the

calculation of the braking distance at a maximum lever operating force (bottom up or 180 N).

b) Optional brake-force application device

It is permissible to use a test mechanism to operate the brake lever, and when such a device is used, it

shall meet the requirements of 4.6.3.4 item a) and shall additionally control the rate of application of

the brake lever force such that 63 % of the intended lever force is applied in not less than 0,2 s.

4.6.3.5 Running — in the braking surfaces

A running-in process shall be conducted on every brake before performance testing is carried out.

Apply the brakes for not less than 3 s to maintain steady deceleration while the bicycle is being ridden

at a speed of approximately 16 km/h. Repeat this operation 10 times.
4.6.3.6 Test method — Test runs under dry conditions

Pedal the test bicycle until the specified test velocity is attained (see ISO 4210-2:2023, Table 1).

Then stop pedalling and apply the brakes. The bicycle shall be brought to a smooth, safe stop [see

ISO 4210-2:2023, 4.6.8.2 item a)].
4.6.3.7 Test method — Test runs under wet conditions

The method shall be as given in 4.6.3.6, with the addition that wetting of the brake system(s) shall

commence not less than 25 m prior to the commencement of braking and shall continue until the bicycle

comes to rest. Excessive amounts of water can be swept from the test track surface between runs.

4.6.3.8 Number of valid test runs

a) If the gradient of the track is less than 0,2 %, the following runs shall be made:

1) five consecutive valid runs under dry conditions;
2) two acclimatization runs under wet conditions (results not recorded);
3) five consecutive valid runs under wet conditions.

b) If the gradient of the track lies between 0,2 % and 0,5 %, the following runs shall be made:

1) six consecutive valid runs under dry conditions with alternate runs in opposite directions;

2) two acclimatization runs under wet conditions (results not recorded);

3) six consecutive valid runs under wet conditions with alternate runs in opposite directions.

A rest period not exceeding 3 min can be taken between successive runs.
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ISO 4210-4:2023(E)
Key
1 water nozzles
2 fork crown
3 front tee-piece
4 wheel rim
Direction of the wheel rotation.
Figure 7 — Water nozzles for rim-brake (front)
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ISO 4210-4:2023(E)
Dimensions in millimetres
Key
1 water nozzles
2 rear tee-piece
3 bicycle frame
4 wheel rim
5 brake assembly
Direction of the wheel rotation.
Figure 8 — Water nozzles for rim-brake (rear)
Key
1 water nozzle
2 two water nozzles
3 hub brake
Direction of the wheel rotation.
Figure 9 — Water nozzles for hub-brake
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ISO 4210-4:2023(E)
Dimensions in millimetres
Key
1 water nozzle
2 bicycle frame
3 rear tee-piece
4 band brake
5 rear hub
Direction of the wheel rotation.
Figure 10 — Water nozzles for band-brake
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ISO 4210-4:2023(E)
Dimensions in millimetres
Key
1 front hub
2 water nozzles
3 flexible pipe
4 suspension-fork leg
5 Y-joint
6 brake-disc
7 disc-brake calliper
Direction of the wheel rotation.
Figure 11 — Water nozzles for disc-brake (front)
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ISO 4210-4:2023(E)
Dimensions in millimetres
Key
1 water nozzles
2 bicycle frame
3 rear hub
4 Y-joint
5 brake disc
6 disc-brake calliper
Direction of the wheel rotation.
Figure 12 — Water nozzles for disc-brake (rear)
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ISO 4210-4:2023(E)
Key
1 water nozzles
2 rear tee-piece
3 bicycle frame
4 brake hub
Direction of the wheel rotation.
Figure 13 — Water nozzles for back-pedal brake
4.6.3.9 Braking distance calculation
The corrected braking distance shall be determined from Formula (1):
Vt⋅−()t
se b
S = (1)
20⋅−V ,278
where
S is the corrected braking distance (m);

V is the specified test velocity (i.e., 6,94 m/s under dry condition, 4,44 m/s under wet condition)

(m/s);

V is 0,8V (i.e., 5,56 m/s under dry condition, 3,56 m/s under wet condition) (m/s);

b s
t is the time at 0,8 V (s);
b s
t is the time at 1 km/h (s).

NOTE To eliminate the effect of variations in the testers' lever operation, the braking distance from an initial

speed is calculated using data from 80 % of the initial speed to 1 km/h (= 0,278 m/s).

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ISO 4210-4:2023(E)
4.6.3.10 Validity of test runs
a) A test run shall be considered invalid if

1) excessive side-skid causing the rider to put his foot to the ground to retain control occurs, or

2) loss of control occurs.

With certain types of braking system, it might not be possible to avoid entirely some skidding of the

rear wheel and tyre assembly during braking. This is considered acceptable provided that 1) or 2)

above do not occur as a result.

b) If the corrected braking distance exceeds the braking distance specified in ISO 4210-2:2023, Table 1,

a test run shall be considered invalid if the velocity at the commencement of the test exceeds the

specified test velocity by more than 1,5 km/h as specified in ISO 4210-2:2023, Table 1.

c) If the corrected braking distance is less than the braking distance specified in ISO 4210-2:2023,

Table 1, a test run shall be considered invalid if the velocity at the commencement of braking is

more than 1,5 km/h below the specified test velocity.

If the corrected braking distance exceeds the braking distance specified in ISO 4210-2:2023,

Table 1, the test run shall be considered valid.
4.6.3.11 Test results
a) Braking under dry conditions.

Depending on the gradient of the test track, the test result shall be the average value of the corrected

braking distance (see 4.6.3.9) of the test results of either 4.6.3.8 item a) 1) or 4.6.3.8 item b) 1).

For conformity with the requirements of ISO 4210-2:2023, 4.6.8.1.2 the above average values shall

not exceed the relevant braking distances specified in ISO 4210-2:2023, Table 1.
b) Braking under wet conditions.

Depending on the gradient of the test track, the test result shall be the average value of the corrected

braking distances (see 4.6.3.9) of the test results of either 4.6.3.8 item a) 3) or 4.6.3.8 item b) 3).

For conformity with the requirements of ISO 4210-2:2023, 4.6.8.1.2, the above average values shall

not exceed the relevant braking distances specified in ISO 4210-2:2023, Table 1.

c) Ratio between wet and dry braking performance for city and trekking, young adult and mountain

bicycles.

Because the wet and dry braking distances are measured at different test velocities, a simple

comparison of braking distances is not meaningful. Therefore, a comparison shall be made of

equivalent, calculated values, using Formula (2):
16 25
brakeperformancewet:brakeperformancedry= : (2)
W D
c c
where
is the corrected braking distance in dry conditions (m);
is the corrected braking distance in wet conditions (m).
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ISO 4210-4:2023(E)
4.6.4 Back-pedal brake linearity test

This test shall be conducted on a fully assembled bicycle. The output force for a back-pedal brake

shall be measured tangentially to the circumference of the rear tyre, when the wheel is rotated in the

direction of forward movement, while a force of between 90 N and 300 N is being applied to the pedal at

right angles to the crank and in the direction of braking.

The braking force reading shall be taken during a steady pull and after one revolution of the wheel. A

minimum of five results, each at a different pedal force level, shall be taken. Each result shall be the

average of three individual readings at the same load level.

The results shall be plotted on a graph, showing the line of best fit and the ±20 % limit lines obtained by

the method of least squares outlined in Annex A.
4.6.5 Machine test method
4.6.5.1 General

The machine test allows to verify the braking forces are sufficient to reach the braking distance

requirements from measurements of the individual braking forces of the front and rear brakes on a

drum or belt.
NOTE See ISO 4210-2:2023, Table 1.

The relationship between braking distance and braking force is given by the Formula (3):

s 2
F =⋅V (3)
where
F is braking force (N);

m is the standard mass of the bicycle defined as 100 kg for adult bicycle and 60 kg for young

adult bicycle (kg);
S is the required braking distance (m);
V is the initial velocity (m/s).
4.6.5.2 Symbols
F Operating force (i.e. force applied on brake lever or pedal)
F Intended ope
...

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