Aspects of Subjective/Objective Correlation Regarding Vehicle Tyres

An introduction to vehicle steering response dynamics is followed by a discussion of the influence of pneumatic tyres on driver subjective ratings concerning vehicle steering and handling characteristics. An empirical study investigating driver sensitivity to the effects of low profile radial-ply and standard radial-ply tyres is then described. It was found that the subjective ratings of ordinary drivers could be systematically related to objective measures of vehicle directional response. Most important in affecting favourable ratings were short lateral acceleration and yaw rate response times, and higher levels of control gain for these parameters. Low profile radial tyres were rated relatively more favourably than standard radials, mainly in respect of a combination of steering “feel,” stability on dual carriageways, and roadholding on straight roads and motorways (freeways). In contrast, standard radial-ply tyres received relatively higher ratings concerning the amount of steering return strength and the degree of comfort experienced on rural roads.

Future research directions discussed include investigating the effect of these directional response parameters on driver behaviour. Also discussed is the need for a systematic investigation of “steering aesthetics,” where there would be concern for a wide range of influences on driver feedback through the vehicle's steering system, Included would be steering torque, the amount of “work done” in steering, gains and response times for lateral acceleration and yaw rate, and the linearity of response for all of these parameters.