This standard specifies the method for measuring the snow grip performance of truck & bus tyres. To reduce the measurement deviation, this standard adopts the test method of comparing with standard reference test tyre.
It is applicable to the truck & bus tyres.
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.
GB/T 6326 Tyre terms and definitions
3 Terms and definitions
For the purposes of this standard, the terms and definitions established in GB/T 6326 and the following ones apply.
3.1
candidate tyre
tyre that is evaluated by testing
3.2
standard reference test tyre; SRTT
a set of special candidate tyres that are used as a benchmark in an evaluation system These tyres usually have carefully controlled design features to minimize variation and they are produced, controlled and stored according to the relevant standards.
3.3
control tyre
tyre which is used to indirectly obtain the comparison result between candidate tyre and standard reference test tyre by comparing with the candidate tyre and then the standard reference test tyre when the candidate tyre and the standard reference test tyre cannot be directly compared on the same vehicle
3.4
braking test
specified amount of anti-blocking brake system (ABS) braking carried out repeatedly on the same tyre in a short time
3.5
mean fully developed deceleration; mfdd
mean deceleration calculated according to the measuring distance recorded when the vehicle slows down between two specified speeds
3.6
snow grip index; SG
ratio of the snow grip performance between the candidate tyre and the standard reference test tyre
3.7
acceleration test
specified amount of traction controlled acceleration test carried out repeatedly on the same tyre in a short time
3.8
acceleration force
acting force generated by applying acceleration moment, in Newtons
3.9
acceleration force coefficient; AFC
ratio of acceleration force to vertical load
3.10
average acceleration; AA
average acceleration calculated according to the measuring distance recorded when the vehicle accelerates between two specified speeds
GB/T 33830-2017 The following standards are cited：
