[F12. DEFINITIONS U.K.
For the purposes of testing wet grip of C1 tyres, the following definitions apply:
‘ test run ’ means a single pass of a loaded tyre over a given test track surface;
‘ test tyre(s) ’ means a candidate tyre, a reference tyre or a control tyre or tyre set that is used in a test run;
‘candidate tyre(s) (T) ’ means a tyre or a tyre set that is tested for the purpose of calculating its wet grip index;
‘reference tyre(s) (R) ’ means a tyre or a tyre set that has the characteristics indicated in ASTM F 2493-08 and referred to as Standard Reference Test Tyre 16 inches (SRTT16″);
‘control tyre(s) (C) ’ means an intermediate tyre or a set of intermediate tyres which is used when the candidate tyre and the reference tyre cannot be directly compared on the same vehicle;
‘ braking force of a tyre ’ means the longitudinal force, expressed in newton, resulting from braking torque application;
‘braking force coefficient of a tyre (BFC) ’ means the ratio of the braking force to the vertical load;
‘ peak braking force coefficient of a tyre ’ means the maximum value of a tyre braking force coefficient that occurs prior to wheel lockup as the braking torque is progressively increased;
‘ lockup of a wheel ’ means the condition of a wheel in which its rotational velocity about the wheel spin axis is zero and it is prevented from rotating in the presence of applied wheel torque;
‘ vertical load ’ means the load in newton imposed on the tyre perpendicular to the road surface;
‘ tyre test vehicle ’ means a dedicated special purpose vehicle which has instruments to measure the vertical and the longitudinal forces on one test tyre during braking.]