The Calculation of Motorcycle Speeds from Sliding Distances

Tests have been performed to investigate how the average deceleration experienced by a motorcycle sliding to rest on its side from high speed compares with the friction measured in a low-speed drag test. This has been done both by launching motorcycles from a low platform, and by allowing them to fall to their sides from an upright position, from speeds between 32 and 90 km/h.

It was found that the friction measured in the low-speed drag tests gave a value close to the high-speed sliding value. The friction was affected by the road surface texture, the presence of prominent side projections, and the wearing away of these projections during the slide. Some speed dependence was noted in the upright-launch tests which appears to be due to the “digging-in” of the machine as it falls to the road, rather than an effect of the sliding friction itself.