ISO 6597:2005

Road vehicles — Hydraulic braking systems, including those with electronic control functions, for motor vehicles — Test procedures

ISO 6597:2005 specifies the method of testing the hydraulic braking systems of vehicles of categories M and N which are built to comply with ECE-R 13/09, including supplements 1 to 7.The values in square brackets [ ] are taken from ECE Regulation No. 13 for information. Hydraulic braking systems include vacuum-assisted and power hydraulic-assisted braking systems as well as full power hydraulic braking systems.

Véhicules routiers — Systèmes de freinage hydraulique, y compris ceux à fonction de commande électronique, pour véhicules à moteur — Modes opératoires d'essai

General Information

• Status: Published
• Publication Date: 28-Jun-2005
• ICS: 43.040.40 - Braking systems
• Technical Committee: ISO/TC 22/SC 33 - Vehicle dynamics and chassis components
• Drafting Committee: ISO/TC 22/SC 33 - Vehicle dynamics and chassis components
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 19-Jul-2019

Relations

• Revises: ISO 6597:2002 - Road vehicles — Motor vehicles with hydraulic braking systems with and without antilock device — Measurement of braking performance
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 6597
Fourth edition
2005-07-01


Road vehicles — Hydraulic braking
systems, including those with electronic
control functions, for motor vehicles —
Test procedures
Véhicules routiers — Systèmes de freinage hydraulique, y compris ceux
à fonction de commande électronique, pour véhicules à moteur —
Modes opératoires d'essai





Reference number
ISO 6597:2005(E)
©
ISO 2005

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ISO 6597:2005(E)
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ISO 6597:2005(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Symbols . 4
5 Test site conditions . 5
5.1 Road conditions. 5
5.2 Test area for vehicles with an anti-lock braking function (ABS) . 5
5.3 Ambient conditions . 6
6 General information. 6
7 Preliminary comments on test procedures and requirements . 6
8 Recommended test order . 8
Annex A (normative) Pre-test phase and static tests. 10
Annex B (normative) Basic performance test — Unladen . 15
Annex C (normative) Failure test — Unladen. 17
Annex D (normative) ABS function tests with the vehicle unladen. 22
Annex E (normative) ABS function tests — with the vehicle laden. 27
Annex F (normative) Failure test — Laden. 31
Annex G (normative) Basic performance test — Laden. 33
Annex H (normative) Special test . 41
Annex I (normative) Braking systems with energy assistance — Tests for vehicles with vacuum
or hydraulic boosters or full power braking systems. 42

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ISO 6597:2005(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.
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 6597 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 2, Braking
systems and equipment.
This fourth edition cancels and replaces the third edition (ISO 6597:2002), which has been technically revised.
This fourth edition incorporates the relevant portions of the International Standard ISO 11835: “Road Vehicles-
Motor vehicles. Measurement of braking performance under ABS operation” for testing vehicles which are
fitted with anti lock function.

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INTERNATIONAL STANDARD ISO 6597:2005(E)

Road vehicles — Hydraulic braking systems, including those
with electronic control functions, for motor vehicles — Test
procedures
1 Scope
This International Standard specifies the method of testing the hydraulic braking systems of vehicles of
categories M and N which are built to comply with ECE-R 13/09, including supplements 1 to 7. The values in
square brackets [ ] are taken from ECE Regulation No. 13 for information.
Hydraulic braking systems include vacuum-assisted and power hydraulic-assisted braking systems as well as
full power hydraulic braking systems.
NOTE Test methods covering the Electrical Regenerative Braking Systems of Electrical and Hybrid Vehicles are not
included in this edition. This omission may be corrected by a further annex once these vehicles are in more common use
and suitable practical test methods have been developed.
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.
ECE Regulation No. 13, Uniform provisions concerning the approval of vehicles with regard to braking,
incorporating the 09 series of amendments including supplements 1 to 7
ECE R.E.3, Consolidated Resolution on the Construction of Vehicles
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
vehicle categories as defined in ECE R.E.3

3.1.1
category M
power-driven vehicles having at least four wheels and used for the carriage of passengers
3.1.2
category N
power-driven vehicles having at least four wheels and used for carriage of goods
3.2
categories of anti-lock braking function (ABS) as defined in ECE Regulation No. 13, Annex 13

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ISO 6597:2005(E)
3.2.1
category 1
that which meets all the requirements of ECE R 13, Annex 13
3.2.2
category 2
that which meets all the requirements of ECE R 13, Annex 13 except paragraph 5.3.5.
NOTE No braking rate on split-adhesion surfaces is prescribed.
3.2.3
category 3
that which meets all the requirements of ECE R 13, Annex 13 except paragraphs 5.3.4 and 5.3.5
NOTE All split-adhesion tests are omitted.
3.3
vehicle loading

3.3.1
laden vehicle
vehicle laden to its maximum technically permissible mass M as specified by the vehicle manufacturer and
max
acknowledged by the Technical Services
NOTE This mass may exceed the “maximum authorized total mass” permitted by national regulations. Mass
distribution on the axles is to be stated by the vehicle manufacturer. In the event of several load distribution patterns being
planned, the distribution of the maximum mass among the axles is such that the load on each axle is proportional to that
maximum technically permissible load for that axle.
3.3.2
unladen vehicle
vehicle at its kerb mass [without load or occupant but with the fuel tank filled at the start of the test to at least
90 % of the capacity stated by the vehicle manufacturer and complete with cooling fluid and lubricants, and
tools and spare wheel(s)]
NOTE During the tests, the fuel quantity is maintained at least at 50 % of the tank capacity, with an allowed increase
of up to 200 kg over the unladen vehicle level. This comprises, for instance, the driver, one observer and instrumentation.
If necessary, some vehicle mass may have to be removed. For a vehicle without a body, the manufacturer declares the
minimum mass which has to be reached on each axle, to represent the vehicle with a body and spare wheel(s) if these
provisions are foreseen.
3.4
hydraulic pressures (Booster and Full Power Systems)

3.4.1
cut-in pressure
system operational pressure in an energy storage device at which the energy source is reconnected
3.4.2
cut-out pressure
system operational pressure in an energy storage device at which the energy source is disconnected
3.5
cold brakes
brakes, the hottest of which has an initial temperature, when measured on the disc or on the outside of the
drum or on the brake linings, lower than 100 °C before each stop
NOTE With the exception of the hot braking performance test, all other tests are carried out with the brakes in this
cold condition.
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ISO 6597:2005(E)
3.6
wheel control in anti-lock braking (ABS) functions

3.6.1
directly controlled wheel
wheel whose braking force is modulated according to data provided at least by its own sensor
3.6.2
indirectly controlled wheel
wheel whose braking force is modulated according to data provided by the sensor(s) of another wheel or other
wheels
NOTE Anti-lock braking functions with select-high control are deemed to include both directly and indirectly controlled
wheels. In functions with select-low control, all sensed wheels are deemed to be directly controlled wheels.
3.7
full cycling
that state of the anti-lock system in which the brake force is repeatedly modulated to prevent the directly
controlled wheels from locking
NOTE Brake applications where modulation only occurs once during the stop are not considered to meet this
definition.
3.8
Electronic braking system (EBS)
braking system in which control is generated and processed as an electrical signal in the control transmission
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ISO 6597:2005(E)
4 Symbols
Table 1 — Symbols
Symbols Meaning Unit
E Wheelbase m
F Force N
Normal reaction of road surface under dynamic conditions with the anti-lock system
F N
dyn
operative
F Normal reaction of road surface on axle i (f or r) under static conditions N
i
F F on axle i (f or r) in case of power-driven vehicles N
idyn dyn
2 2
g Acceleration due to gravity (9,81 m/s) m/s
Height of centre of gravity specified by the manufacturer and agreed by the Technical
h m
Service conducting the approval test
k Coefficient of adhesion between tyre and road 1
k k-factor of the front axle 1
f
k k-value determined on high-adhesion surface 1
H
k k-value determined on the low-adhesion surface 1
L
k Value of adhesion for 100 % slip 1
lock
k Mean k-factor of the vehicle (dynamically weighted) 1
m
k Maximum value of the curve “adhesion versus slip” 1
peak
k k-factor of the rear axle 1
r
M Mass of individual vehicle kg
M Permissible maximum mass kg
max
p Pressure bar
s Stopping distance m
t Time interval s
t Mean value of several measurements of t s
m
t Minimum value of t s
min
v Vehicle speed km/h
v Maximum speed of vehicle (declared by the manufacturer) km/h
max
z Braking rate 1
z Braking rate z of the vehicle with the antilock system operative 1
AL
z Mean braking rate 1
m
z z of the power-driven vehicle on a “split surface” 1
MALS AL
The adhesion utilized by the vehicle: quotient of the maximum braking rate with the
ε
anti-lock system operative (z ) and the coefficient of adhesion (k) values for high and 1
AL
ε , ε
low-adhesion surfaces respectively
L H
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ISO 6597:2005(E)
5 Test site conditions
5.1 Road conditions
5.1.1 Surface
Except for ABS tests (see 5.2), the road surface shall be a smooth, hard-surfaced roadway of asphalt,
concrete, or other surface with an equivalent coefficient of adhesion.
The road surface shall be free from loose material and dry for those tests requiring high adhesion.
5.1.2 Gradient
The road surface shall be substantially level; a tolerance of ± 1 % average gradient, measured over a
minimum distance of 50 m, is allowed.
The type II test or the braking system hill-holding test may be conducted on a specified gradient or on a level
road using a towing vehicle.
5.1.3 Camber
The camber or transverse gradient across the road surface shall not exceed 2 %.
5.2 Test area for vehicles with an anti-lock braking function (ABS)
5.2.1 An area for tests on vehicles with ABS shall be provided consisting of a surface providing a peak
coefficient of adhesion (k u 0,4) and of a size sufficient to enable the tests to be performed in safety.
peak
Furthermore this area shall be preceded and followed by a surface which provides a peak coefficient of
adhesion of about 0,8, which is of sufficient length on the approach side to enable the test speeds to be
attained.
For testing vehicles fitted with ABS of categories 1 or 2, a low-adhesion surface shall have a high-adhesion
surface on at least one side so as to enable the split-adhesion tests to be performed. Each surface shall be
sufficiently wide to allow the separate determination of its peak coefficient of adhesion.
5.2.2 The surfaces used for the split adhesion tests shall be such that:
k W [0,5] and k /k W [2]
H H L
If any doubt arises that this requirement is met, the peak coefficient of adhesion shall be ascertained by using
the procedure detailed in D.3. It is always necessary to measure the peak coefficient of adhesion when testing
a vehicle fitted with ABS of categories 1 or 2.
5.2.3 For tests of the ABS, the track used shall be regularly characterized by preparation (for the low-
adhesion surface) of a curve showing the actual coefficient of adhesion versus slip from 0 to 100 % slip at a
speed of approximately 40 km/h.
NOTE Plotting this graph may require a special ABS capable of operating at any preset level of slip.
The peak value k and the value at 100 % slip k shall be measured and the ratio k /k calculated
peak lock peak lock
and rounded to 1 decimal place.
For the surface to qualify, this ratio shall be:
1 u k /k u 2
peak lock
Information on the method of measurement of adhesion levels shall be made available.
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ISO 6597:2005(E)
5.3 Ambient conditions
The wind speed shall not exceed an average of 5 m/s.
The air temperature shall not exceed 35 °C. In exceptional circumstances, up to 45 °C may be accepted.
This shall be recorded in the test report.
6 General information
6.1 Deceleration measurements used in this procedure refer to the “mean fully developed deceleration”
(MFDD). When reference is made to “prescribed effectiveness”, this is the MFDD and stopping distance
performance required in ECE Regulation No. 13 for the relevant test.
6.2 The use of either pedal-application machines or of robots does not reflect real-life vehicle braking and
should be discouraged.
6.3 The determination of the optimum vehicle braking performance shall be entrusted to skilled test drivers.
This shall be achieved without wheel-locking except immediately before stopping and without significant
deviation being caused by braking. A period of familiarization with the vehicle braking, steering and
suspension systems should be allowed.
7 Preliminary comments on test procedures and requirements
7.1 The tests should be carried out in the recommended sequence described in Table 2, but it is recognized
that practical circumstances may require variations from this sequence. However, because of thermal
influence on friction material behaviour, it is most strongly recommended that:
 the fade test is performed at the end of the sequence; and
 adhesion utilization tests be performed before the corresponding k factor determination.
Any variation in the recommended sequence shall be noted.
7.2 To reduce load changes, all unladen tests are grouped together and followed by the laden tests.
7.3 The parking braking system tests and the response time measurements may be carried out at any time
selected by the vehicle manufacturer and agreed with the Technical Services during the testing sequence.
7.4 A preliminary series of five braking system applications may be carried out for vehicle familiarization.
Because the total number of stops can significantly change the thermal and mechanical properties of the
friction materials (and thus possibly the vehicle braking performance), it is recommended that each test
condition be run no more than four times.
7.5 Re-testing in the course of the full procedure shall be avoided, although one or two extra stops are
unlikely to prejudice subsequent road test results.
7.6 Full or partial re-tests, after a failed test or to approve alternative braking system components, shall
again follow this procedure and with particular emphasis on the vehicle preparation and bedding procedures.
7.7 In order to avoid delays, tests may be carried out under adverse conditions but with due consideration
for safety; such adverse conditions shall be reported. Any failed test under such conditions may be repeated
under the correct conditions, but it is not necessary that all tests be repeated.
7.8 During the tests with the engine connected, on vehicles with a manual gearbox, the clutch may be
disengaged just before the vehicle stops, to avoid stalling the engine.
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ISO 6597:2005(E)
7.9 Tests with the engine connected should be carried out in the appropriate gear, defined as the lowest
gear which would normally be used to reach the speed without exceeding the manufacturer's recommended
maximum engine speed.
7.10 Control forces should be applied rapidly, but without significant overshoot, and then be maintained
constant during the stop to allow meaningful measurements to be made. Any departure from this International
Standard shall be mentioned in the appropriate test procedure paragraph.
7.11 All tests start with cold brakes, except the hot performance tests.
7.12 During all phases of this procedure, any unusual braking performance characteristics, such as deviation
or vibration, shall be reported.
7.13 Each specific failure mode appropriate to the vehicle braking equipment shall be considered and the
service braking system shall be checked for the worst case failure modes (for EBS see Annex 18 reference
in A.1 d)).
7.14 Where fault conditions are imposed on the braking system, they shall be removed after the appropriate
test has been conducted and the correct operation of the braking system shall then be verified.
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ISO 6597:2005(E)
8 Recommended test order
Table 2 — Recommended test order
Engine status
ECE Reg. 13
Test required
Connected Disconnected
Paragraph/Comments
or in gear or neutral
A — Pre-Test Phase
1 Documents required A1, A18
2 Preparation (instrumentation, bedding, etc.)
3 Line pressure vs. control force, at engine idling  Common practice
after boost is established (not an R 13 requirement)
4 Characteristic of pressure reduction valve
5 Line pressure vs. time curve (vehicle stationary)  A3 § 4
6 ABS warning lamp and mode change check  A13, § 4.1, 4.1.1, 4.1.2
7 Additional tests on vehicles equipped with EBS  § 5.2.1.27.1
B — Basic Performance Tests — unladen
1 Type 0 performance X
A4 § 1.4.2, 2.1.1 plot deceleration
vs. line pressure
2 Type 0 performance X A4 § 1.4.3
3 Wheel locking sequence  A10 § 3.1.4.2-4

C — Failure Tests — unladen
1 Partial system failure Type 0 performance X A4 § 2.2
2 Failed load sensing-proportioning valve control X A10 § 6
3 Sensor fault memory test  A13 § 4.1.1
4 Failure of the energy source on vehicles  § 5.2.1.27.5, 5.2.1.27.6,
equipped with EBS 5.2.1.27.7, 5.2.1.27.8
D — ABS Tests — unladen
1 ABS – failed case X A13 § 4.3, A 4 § 2.4, 2.2
2 ABS – adhesion, utilisation on high adhesion X A13 § 5.2.2
3 ABS – determination of k X A13 - App.2
H
4 ABS – adhesion, utilisation on low adhesion X A13 § 5.2.2
5 ABS – determination of k X A13 - App.2
L
6 ABS – wheel behaviour test on homogeneous X A13 § 5.3
surfaces
7 ABS – transition from high to low adhesion X A13 § 5.3.2
8 ABS – transition from low to high adhesion X A13 § 5.3.3
9 ABS – split adhesion test X A13 App.3 for ABS cat. 1 or 2

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ISO 6597:2005(E)
Table 2 (continued)
Engine status
ECE Reg. 13
Test required
Connected Disconnected
Paragraph/Comments
or in gear or neutral
E — ABS Tests — laden
1 ABS – failed case  as D1
2 ABS – adhesion utilisation on high adhesion X as D2
3 ABS – determination of k X as D3
H
4 ABS – adhesion utilisation on low adhesion X as D4
5 ABS – determination of k X as D5
L
6 ABS – wheel behaviour tests on homogeneous X as D6
surfaces
7 ABS – transition from high to low adhesion X as D7
8 ABS – transition from low to high adhesion X as D8
9 ABS – split adhesion test X as D9
10 ABS – energy consumption X A13 § 5.1
F — Failure Tests — laden
1 Partial system failure Type 0 performance X A4 § 2.2
2 Failed load sensing /proportioning valve X A10 § 6
3 Failed booster test X § 5.2.1.2.7 & A4 § 1.4.2, 2.2
G — Basic Performance Tests — laden
1 Type 0 performance X as B1
2 Type 0 performance X as B2
3 Wheel locking sequence test  A10 § 3.1.4.2 to 3.1.4.4
4 Response time X A4 § 4.1.1
5 Type II (engine braking, only M3 urban buses) X A4 § 1.6 & 1.8.2 if applicable
6 Parking braking system dynamic test X A4 § 2.3.6
7 Parking braking system static test X A4 § 2.3.1 to 2.3.5
8 Additional tests on vehicles equipped with  § 5.2.1.26 to § 5.2.1.26.4
electrical parking brake
9 Type I fade test X A4 § 1.5.1
10 Type 0 hot performance X A4 § 1.5.3.1/2, 1.5.4
H — Special test
Whilst not directly required by ECE Regulation No. 13, this test is called for in Directive 71/320 & 98/12 EEC
1 Temporary use spare wheels, laden X EEC Directive, Annex XIII
I — Special tests — Vacuum/hydr. assisted or power hydraulic actuation
1 General information
2 Vacuum booster system tests  A7B § 1.2, 2.2
3 Hydraulic booster system tests  A7C § 1.2, 2.1.2/3
4 Hydraulic full power system tests X 5.2.1.5 & A7C § 1.2, 2.1.2/3
5 Low pressure warning
X
Indicates the status of the engine (connected or disconnected)

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ISO 6597:2005(E)
Annex A
(normative)

Pre-test phase and static tests
A.1 Documents and basic data
The vehicle shall be verified based upon the documentation as follows:
a) Main technical data according to Annex 2 of ECE Regulation No. 13.
b) Layout and list of the elements of the braking system.
c) Braking system performance calculation (optional if vehicle is equipped with ABS).
d) Documentation according to Annex 18 of ECE Regulation No. 13, if the vehicle is equipped with EBS.
This documentation includes an explanation of design provisions guaranteeing compliance with all
relevant parts of ECE Regulation No. 13 paragraphs 5.1.4.7, 5.2.1.8 and 5.2.1.27 which deal with the
special requirements for the verification of the correct operational status, brake force compensation and
for EBS. This documentation may also indicate the worst-case failures for EBS.
e) Report/approval of EMC Tests (if vehicle is equipped with ABS or EBS) in accordance with ECE
Regulation No. 10.02.
A.2 Vehicle preparation
A.2.1 Vehicle loading
See 3.3.
A.2.2 Basic instrumentation needed for vehicle tests
The vehicle shall be prepared for testing by the addition of the following instruments and/or calibration of
existing standard instruments, as required. Other instruments may be useful in providing accurate data, but
care needs to be exercised to ensure that instruments added to the standard vehicle braking equipment do
not significantly affect the braking system performance.
All the following appropriate data acquisition system instruments shall be checked to ensure that they are
functioning correctly and, with the vehicle stationary on a level test surface and without any brake application,
all the instruments shall be set to zero:
a) control force gauge for the service braking systems;
b) control force gauge for the parking braking system;
c) control force gauge for the secondary braking system, if this system is not part of either the service or the
parking braking system;
d) decelerometer;
e) speed-measuring device or calibrated speedometer;
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ISO 6597:2005(E)
f) stopping-distance-measuring means;
g) time-measuring means;
h) brake temperature indicating system;
i) line pressure gauges/transducers. Regulations call for pressure measurements to be made at the least
favourable brake actuator and in other parts of the system;
j) optional instruments may include wheel lock indicators, control device travel gauges.
A.2.3 Additional instrumentation needed for test on vehicles with ABS
a) vehicle speed and, optionally, stopping distance and/or deceleration-measuring equipment shall be
capable of producing a permanent record of these variables during braking. The acquisition system shall
also produce a time base;
b) optional equipment to ascertain when and for what period the wheels directly controlled by an ABS
actually lock during the test;
c) for ABS/EBS which depend on stored energy assistance rather than an electrically powered energy
source, a device shall be provided to isolate the energy source;
d) it is standard practice to use adjustable pressure-limiting valves in the line to each wheel brake that will
be used during the determination of k or k ;
f r
e) optional equipment to show the point of transition of the vehicle from the low to the high-adhesion surface
on the permanent record;
f) optional means of measuring steering wheel angles (only for vehicles which are fitted with a category 1
ABS).
A.2.4 Provisions for failure simulation
The vehicle shall be equipped with the necessary added devices, piping and wiring according to the
manufacturer's recommendations and agreed with the Technical Services, to provide the required failure
simulations. Such added devices, piping and wiring shall not significantly affect the intact and/or failed braking
system performance.
When a leakage is simulated, the brake fluid shall be returned to the reservoir.
In the electric part of the braking system, a failure generally corresponds to a disconnection, but a short circuit
or a ground connection may be specified by the manufacturer in certain instances. This may be done by using
prepared components or sections of wiring.
A.2.5 Tyre conditions
The tyres shall be inflated to the vehicle manufacturer's recommended pressure levels.
It is
...