Continuous reading, fixed slip skid testers

8 Continuous reading, fixed slip skid testers 

The continuous reading, fixed slip technique is similar to the abovementioned locked wheel skid tester technique but it provides a record of skid resistance along the whole length of the test track surface. It also enables averages to be obtained for specified test segments. Hence, the instantaneous friction reading is recorded and the BFC for each friction length is calculated and recorded. 

The devices/equipment used are known as continuous reading, fixed-slip measuring equipment. The testing procedure and method of measurement are carried out in accordance to ASTM E 2340 (2011). 

The measuring apparatus consisting of a test wheel with a smooth tyre (ASTM E 1551 2008), force or torque transducers and a watering system is usually built into a vehicle or into a trailer towed by a vehicle. 

Measurements are taken on a wet surface at a constant slip ratio of usually 15% and at a standard test speed within the 20 to 80 km/h range. 

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