ISO 8709:2010

INTERNATIONAL ISO
STANDARD 8709
Second edition
2010-04-15
Mopeds — Brakes and brake systems —
Tests and measurement methods
Cyclomoteurs — Freins et systèmes de freinage — Méthodes d'essai et
de mesure
Reference number
©
ISO 2010
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ii © ISO 2010 – All rights reserved

Contents Page
Foreword .iv
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
3.1 Vehicle categories .2
3.2 Brake system and components .2
3.3 Types of brake systems.2
3.4 Moped loading .3
3.5 Test parameters.3
4 Test site conditions.4
4.1 Test surface .4
4.2 Wind speed .4
4.3 Ambient temperature .5
4.4 Test lane for dynamic tests .5
5 Moped preparation .5
5.1 Tyres .5
5.2 Engine idle speed .5
5.3 Mass distribution.5
5.4 Instrumentation .5
5.5 Burnishing.7
6 Test requirements .7
6.1 Brakes.7
6.2 Brake temperature measurement .8
6.3 Application of control forces.8
6.4 Test sequence.8
6.5 Rider.8
6.6 Automatic transmission.9
6.7 Moped position and wheel lock .9
6.8 Test speed tolerance.9
6.9 Measurement of dynamic performance .9
6.10 Test report.10
7 Test procedures.10
7.1 Dry stop test (single brake control actuated).10
7.2 Wet brake test .11
7.3 Parking brake system test.13
7.4 Power-assisted brake system failure test.14
Annex A (normative) Specimen format for test result sheet.16
Bibliography.21

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 8709 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 23, Mopeds.
This second edition cancels and replaces the first edition (ISO 8709:1995), which has been technically revised.
It also incorporates the Technical Corrigendum ISO 8709:1995/Cor.1:1998.

iv © ISO 2010 – All rights reserved

INTERNATIONAL STANDARD ISO 8709:2010(E)

Mopeds — Brakes and brake systems — Tests and
measurement methods
1 Scope
This International Standard specifies tests and measurement methods for service brake systems and, where
applicable, associated parking brake systems of two-wheeled mopeds (3-1) and three-wheeled mopeds (3-2)
which are intended for use on public roads, in order to establish uniform worldwide test procedures for braking
systems.
This International Standard does not cover mopeds which:
⎯ have a maximum speed of less than 25 km/h;
⎯ are equipped for disabled riders.
This International Standard sets out the following types of tests:
⎯ dynamic tests:
⎯ dry stop test (single brake control actuated);
⎯ wet brake test;
⎯ parking brake system test;
⎯ power-assisted brake system failure test.
NOTE The test methods (application, condition of the moped, test procedure and parameters, measurement of
performances) for all the tests defined in this International Standard are equivalent to the corresponding test methods
prescribed by UNECE Global Technical Regulation No. 3.
2 Normative references
The following referenced documents are indispensable for the application 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 3779, Road vehicles — Vehicle identification number (VIN) — Content and structure
ISO 7116, Mopeds — Measurement method for determining maximum speed
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 Vehicle categories
NOTE Vehicle categories as defined in this clause correspond to those given in UNECE Special Resolution No. 1.
3.1.1
category 3 vehicle
power driven vehicle with 2 or 3 wheels designed and constructed for the carriage of persons, of goods, or of
persons and goods
3.1.1.1
category 3-1 vehicle
two-wheeled moped
two-wheeled vehicle with an engine cylinder capacity not exceeding 50 cm in the case of a thermic engine
and a maximum design speed not exceeding 50 km/h, whatever the means of propulsion
3.1.1.2
category 3-2 vehicle
three-wheeled moped
three-wheeled vehicle of any wheel arrangement with an engine cylinder capacity not exceeding 50 cm in the
case of a thermic engine and a maximum design speed not exceeding 50 km/h, whatever the means of
propulsion
3.2 Brake system and components
3.2.1
brake system
combination of parts (other than the engine), consisting of the control, the transmission(s) and the brake(s),
the function of which is progressively to reduce the speed of a moving moped, bring it to a halt and keep it
stationary if it is already halted
3.2.2
control
part actuated directly by the rider to supply to the transmission or control the energy required for braking the
moped
3.2.3
transmission
combination of components which provide the functional link between the control and the brake
3.2.4
brake
parts of the brake system in which the forces opposing the movement of the moped are developed
3.3 Types of brake systems
3.3.1
service brake system
brake system which is used for slowing the moped when in motion
3.3.1.1
single brake system
service brake system which acts on only one axle
3.3.1.2
combined brake system
CBS
〈two-wheeled mopeds〉 service brake system whereby at least two brakes on different wheels are actuated by
the operation of a single control
2 © ISO 2010 – All rights reserved

3.3.1.3
combined brake system
CBS
〈three-wheeled mopeds〉 service brake system whereby the brakes on all the wheels are actuated by the
operation of a single control
3.3.1.4
secondary brake system
second service brake system on a vehicle equipped with a combined brake system
3.3.2
power-assisted brake system
brake system in which the energy necessary to produce the braking force is supplied by the physical effort of
the rider assisted by one or more energy supplying devices
EXAMPLE Vacuum assisted (with vacuum booster).
3.4 Moped loading
NOTE Vehicle masses as defined in this clause correspond to those given in UNECE Special Resolution No. 1.
3.4.1
laden moped
moped laden so as to reach its gross vehicle mass
3.4.2
lightly loaded moped
moped in the condition of mass in running order to which 15 kg are added, in order to account for the test
equipment as described in 5.4
3.4.3
gross vehicle mass
maximum mass of the fully laden solo vehicle, based on its construction and design performances, as
declared by the manufacturer
3.4.4
mass in running order
sum of unladen vehicle mass and 75 kg, in order to account for the driver's mass
3.4.5
unladen vehicle mass
mass of the vehicle with bodywork and all factory fitted equipment, electrical and auxiliary equipment for
normal operation of vehicle, including liquids (fuel tank filled to at least 90 % of the rated capacity and the
other liquid containing systems to 100 % of the capacity specified by the manufacturer), tools, fire extinguisher,
standard spare parts, chocks and spare wheel, if fitted
3.5 Test parameters
3.5.1
test speed
V
moped speed measured at the moment the rider begins to actuate the brake control(s)
NOTE For tests where simultaneous actuation of two controls is specified, the moped speed is taken from the
moment the first control is actuated.
3.5.2
mean fully developed deceleration
MFDD
d
m
average deceleration calculated from the moment the moped reaches 80 % of the test speed until the moment
the moped reaches 10 % of the test speed
3.5.3
stopping distance
S
distance travelled by the moped, measured from the moment the rider begins to actuate the braking system
control until the moment the moped comes to a stop
NOTE For tests where simultaneous actuation of two controls is specified, the distance travelled is taken from the
moment the first control is actuated.
3.6
baseline test
stop or series of stops carried out in order to confirm the performance of the brake prior to subjecting it to a
further test, such as the heating procedure or wet brake stop
3.7
engine disconnected
condition when the engine is no longer connected to the driving wheel(s)
3.8
initial brake temperature
temperature of the hottest brake before any brake application
3.9
maximum speed
V
max
speed which the moped can attain when tested in accordance with ISO 7116
3.10
peak braking coefficient
PBC
measure of tyre to road surface friction based on the maximum deceleration of a rolling tyre
3.11
wheel lock
condition that occurs when there is a slip ratio of 1,00
4 Test site conditions
4.1 Test surface
The test surface for dynamic tests shall be clean, dry and substantially level (i.e. it shall not have a gradient in
excess of 1 %). The surface shall afford good adhesion, i.e. it shall have a nominal peak braking coefficient
(PBC) of 0,9, unless otherwise specified.
The parking brake system test is conducted on a specified gradient. The specified test slope shall have a
clean and dry surface that does not deform under the weight of the moped.
4.2 Wind speed
The average wind speed shall not exceed 5 m/s.
4 © ISO 2010 – All rights reserved

4.3 Ambient temperature
The ambient temperature shall be between 4 °C and 45 °C.
4.4 Test lane for dynamic tests
The test area immediately after the point at which the test is to commence shall be marked with a lane of
sufficient length for the moped to be brought to a stop.
In the case of two-wheeled mopeds (3-1), this lane shall be 2,5 m wide. In the case of three-wheeled mopeds
(3-2), this lane shall have a width of 2,5 m plus the moped width.
5 Moped preparation
5.1 Tyres
The tyres shall be inflated to the moped manufacturer's recommended pressure levels as appropriate to the
vehicle loading condition for the test.
5.2 Engine idle speed
The engine idle speed shall be set to the moped manufacturer's specification.
5.3 Mass distribution
The mass distribution on the axles for laden moped tests shall be in accordance with the moped
manufacturer's specifications and shall be noted in the test report.
5.4 Instrumentation
The moped shall be prepared for the tests specified in Table 1 by the provision, the calibration, or the
provision and calibration of existing instruments, as required.
Optional instruments may be added to provide data, but care shall be taken to ensure that no equipment
significantly affects the brake system performance or the dynamic characteristics of the moped.
Table 1 — Test sequence and related instrumentation
Test Parameter Example of instrument
(to measure/calculate)
Obligatory Optional
0.
Speed Calibrated speedometer, photoelectronic measuring
Burnishing systems
a
procedure
Brake temperature Rubbing thermocouple, embedded thermocouple
Moped mass Load cells, weighbridge
Deceleration Motometer, third wheel, recording deceleration meter

Table 1 (continued)
Test Parameter Example of instrument
(to measure/calculate)
Obligatory Optional
1. Speed Calibrated speedometer, photoelectronic measuring
Dry stop systems
test (single
Brake temperature Rubbing thermocouple, embedded thermocouple
brake
control
Control force Force meter
actuated)
Stopping distance Chalk-pellet gun, third wheel, ink jet marker

or
MFDD (see 6.9.2) Motometer, third wheel, recording deceleration meter
Moped mass Load cells, weighbridge
Force in transmission Hydraulic pressure transducer, cable tension transducer
Control travel Linear potentiometer
2. Speed Calibrated speedometer, photoelectronic measuring
Wet brake systems
a
test
Brake temperature Rubbing thermocouple, embedded thermocouple
Control force Force meter
Moped mass Load cells, weighbridge
Deceleration throughout Motometer, third wheel, recording deceleration meter
braking stop
Distance Third wheel
Force in transmission Hydraulic pressure transducer, cable tension transducer
Control travel Linear potentiometer
3. Time Stopwatch
Parking
Control force Force meter
brake
system
Moped mass Load cells, weighbridge
test
Brake temperature Rubbing thermocouple, embedded thermocouple
Control travel Linear potentiometer
4. Speed Calibrated speedometer, photoelectronic measuring
Power- systems
assisted
Brake temperature Rubbing thermocouple, embedded thermocouple
brake
system
Control force Force meter
failure test
Stopping distance Chalk-pellet gun, third wheel, ink jet marker

or
MFDD (see 6.9.2) Motometer, third wheel, recording deceleration meter
Moped mass Load cells, weighbridge
Force in transmission Hydraulic pressure transducer, cable tension transducer
Control travel Linear potentiometer
a
Where this test result depends on the analysis of a deceleration trace provided by a recording system, the system shall have
damping and frequency-response characteristics, such that the behaviour of the moped under braking is faithfully reproduced.
6 © ISO 2010 – All rights reserved

5.5 Burnishing
5.5.1 General
Prior to submitting a moped for tests, the moped brakes shall be burnished. This procedure may be completed
by the moped's manufacturer.
5.5.2 Moped condition
The moped condition shall be as follows:
a) moped lightly loaded;
b) engine disconnected.
NOTE If the mass of the lightly loaded moped exceeds the mass of the laden moped, the laden condition is used for
the purposes of this subclause.
5.5.3 Procedure
The test procedure shall be as described below.
a) Test speed:
⎯ initial speed: 50 km/h or 0,8 V , whichever is lower;
max
⎯ final speed: 5 km/h to 10 km/h.
b) Brake application: each service brake system control actuated separately.
c) Moped deceleration:
2 2
⎯ single front brake system only: between 3,0 m/s and 3,5 m/s ;
2 2
⎯ single rear brake system only: between 1,5 m/s and 2,0 m/s ;
2 2
⎯ CBS: between 3,5 m/s and 4,0 m/s .
d) Number of decelerations: 100 per brake system.
e) Initial brake temperature before each brake application: u 100 °C.
f) For the first stop, accelerate the moped to the initial speed and then actuate the brake control under the
conditions specified until the final speed is reached. Then, reaccelerate to the initial speed and maintain
that speed until the brake temperature falls to the specified initial value. When these conditions are met,
reapply the brake as specified. Repeat this procedure for the number of specified decelerations. After
burnishing, adjust the brakes in accordance with the moped manufacturer's recommendations.
6 Test requirements
6.1 Brakes
Brakes and brake systems shall not be adjusted at any time during the dynamic tests.
After the tests, the components of the brake system shall be examined for signs of damage, permanent
distortion, friction material detachment and brake fluid leakage.
6.2 Brake temperature measurement
The brake temperature shall be measured at approximately the centre of the braking path of the disc or drum
using:
a) a rubbing thermocouple that is in contact with the surface of the disc or drum; or
b) a thermocouple that is embedded in the friction material.
6.3 Application of control forces
The control forces shall be applied rapidly, up to the prescribed level, and then maintained constant during the
stop.
For a hand control lever, the input force, F, is applied on the control lever's forward surface, perpendicular to
the axis between the central axis of the lever fulcrum and its outermost point, on the plane along which the
control lever rotates (see Figure 1).
Dimensions in millimetres
Key
1 lever fulcrum
F input force
Figure 1 — Force application for hand control l
...