GB/T 18861-2012 English PDF (GBT18861-2012)

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GB/T 18861-2012: Test methods of rolling resistance for motor vehicle tyres and motorcycle tyres -- Multi-point test
GB/T 18861-2012
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 83.160.10
G 41
Replacing GB/T 18861-2002
Test methods of rolling resistance for motor vehicle tyres and
motorcycles tyres - Multi-point test
(ISO 18164:2005, Passenger car, truck, bus and motorcycle tyres - Methods of
measuring rolling resistance, MOD)
ISSUED ON: DECEMBER 31, 2012
IMPLEMENTED ON: SEPTEMBER 01, 2013
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
National Standardization Administration.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 6
4 Measurement methods ... 7
5 Test equipment ... 7
6 Test conditions ... 9
7 Test procedures ... 10
8 Data processing ... 14
9 Data analysis ... 17
Appendix A (Informative) Comparison of chapter numbers between this standard and
ISO 18164:2005 ... 19
Appendix B (Informative) Technical differences between this standard and ISO
18164:2005 and their reasons ... 20
Appendix C (Normative) Accuracy of test equipment ... 21
Appendix D (Informative) Optional test conditions ... 24
Appendix E (Informative) Method for determining the moment of inertia of the drum
and the moment of inertia of the tyre and rim assembly - Deceleration method ... 26
Test methods of rolling resistance for motor vehicle tyres and
motorcycles tyres - Multi-point test
1 Scope
This standard specifies a method, for measuring the rolling resistance of new car, truck
and motorcycle tyres, under controlled laboratory conditions.
This standard applies to new car pneumatic tyres, truck pneumatic tyres, motorcycle
pneumatic tyres, except for tyres only for temporary replacement use.
2 Normative references
The following documents are essential to the application of this document. For the dated
documents, only the versions with the dates indicated are applicable to this document;
for the undated documents, only the latest version (including all the amendments) is
applicable to this standard.
GB/T 2977 Size designation, dimensions, inflation pressure and load capacity for
truck tyres
GB/T 2978 Size designation, dimensions, inflation pressure and load capacity for
passenger car tyres
GB/T 2983 Series of motorcycle tyres (GB/T 2983-2008, ISO 4249-1:1985,
Motorcycle tyres and rims (code-designated series) – Part 1: Tyre; ISO 4249-2:1990,
Motorcycle tyres and rims (code-designated series) -Part 2: Tyre load ratings; ISO
4249-3:2004, Motorcycle tyres and rims (code-designated series) - Part 3: Rims;
ISO 5751-1:2004, Motorcycle tyres and rims (metric series) - Part 1: Design guides;
ISO 5751-2:2004, Motorcycle tyres and rims (metric series) - Part 2: Tyre
dimensions and load-carrying capacities; ISO 5751-3:2004, Motorcycle tyres and
rims (metric series) - Part 3: Range of approved rim contours; ISO 5995-1:1982,
Moped tyres and rims - Part 1: Tyres; ISO 6054-1:1994, Motorcycle tyres and rims
(code-designated series) - Diameter codes 4 to 12 - Part 1: Tyres, NEQ)
GB/T 6326 Tyre terms and definitions (GB/T 6326-2005, ISO 4223-1:2002,
Definitions of some terms used in tyre industry - Part 1: pneumatic tyres, NEQ)
5.1.1 Drum diameter
The diameter of the drum of the testing machine is as follows: The diameter of the drum
for car and motorcycle tyres is at least 1.5 m (the standard drum diameter is 1.7 m); the
diameter of the drum for truck tyres is at least 1.7 m. The values of rolling resistance
and rolling resistance coefficient shall be expressed as values for a 1.7 m drum. It shall
be noted that the rolling resistance results are different for different drum diameters.
According to 9.3, if necessary, different drum diameters can be converted.
5.1.2 Drum surface quality
The outer surface of the drum shall be smooth steel or textured; it shall be kept clean.
The roughness of the steel surface shall comply with the requirements given in C.6. See
Appendix D.4 for textured drumheads.
5.1.3 Drumhead width
The drum surface width shall be greater than the running surface width of the test tyre.
5.2 Test rims
The tyre shall be mounted on the test rim, which is specified in Appendix C.
5.3 Load, positioning, control, instrument accuracy
The tyres, their loads and positioning shall comply with the requirements given in C.3.
The control accuracy shall comply with the provisions of C.4. The instrument accuracy
shall comply with the provisions of C.5.
5.4 Ambient temperature
5.4.1 Standard ambient temperature
The standard ambient temperature is 25 °C. The ambient temperature shall be measured
on the extension line of the wheel axle centerline, at 0.15 m ~ 1 m away from the nearest
sidewall surface of the tyre.
5.4.2 Allowable ambient temperature
If the standard ambient temperature cannot be reached, the test is allowed within the
ambient temperature range of 20 °C ~ 30 °C. However, the test data shall be corrected
to the rolling resistance value under standard ambient temperature conditions,
according to 9.2.
5.4.3 Drum surface temperature
At the beginning of the test, the temperature of the outer peripheral surface of the drum
is approximately the same as the ambient temperature.
pressure of passenger car tyres, truck tyres, motorcycle tyres shall comply with the
provisions of Table 2. The control accuracy of the test starting air pressure shall comply
with the provisions of C.4.1.
6.5 Time and velocity variables of deceleration method
When the deceleration method is selected, the increment of running time (Δt) shall not
be greater than 0.5 s; the variation of test speed shall not be greater than 1 km/h.
6.6 Selected test conditions
If it is necessary to conduct a sensitivity test of tyre pressure, load, speed to tyre rolling
resistance, please refer to the test conditions given in Appendix D.
7 Test procedures
7.1 General
The stages of the test procedure shall be carried out in the order given below.
7.2 Test run
Install the test tyre on the measuring rim. Inflate it according to the test air pressure,
which is specified in 6.4. Install it on the testing machine. Run it for at least 1 hour,
according to the test load specified in 6.3 and at a test speed not lower than that specified
in 6.2.
7.3 Thermal balance
Place the tyre and rim assembly at the test site. Place the test tyre at the test ambient
temperature, to reach thermal equilibrium, to allow the test tyre to reach the ambient
temperature. The thermal equilibrium time of car and motorcycle tyres is more than 3
hours; the thermal equilibrium time of truck tyres is more than 6 hours.
7.4 Air pressure adjustment
After thermal equilibrium, check the air pressure of the test tyre; adjust it to meet the
requirements of 6.4; recheck after 10 minutes, to ensure the specified test air pressure
of the tyre.
7.5 Warm up
Warm up the test tyre and drive it, according to the test load specified in 6.3 and the test
speed specified in 6.2, until its rolling resistance value becomes stable. The minimum
warm-up driving time shall comply with the requirements in Table 3.
- Car tyres and motorcycle tyres: Recommended value is 100 N, but no more than
200 N;
- Truck tyres (load index ≤ 121): Recommended value is 150 N. However, for
equipment specially designed for car tyres or light truck tyres, it shall not
exceed 200 N; OR for equipment specially designed for truck tyres, it shall not
exceed 500 N;
- Truck tyres (l...