Study of Parametric Variation on Braking Performance of a Tyre

Braking Performance of a vehicle is one of the most important parameters when it comes to the safety of a vehicle. With rapidly changing tyre & vehicle technology and driving surfaces, its critical to study and quantify the impact of various operational parameters on braking. This study focusses to determine the level of variability in braking performance of a tyre with respect to change in operational and tyre structural parameters. It would hence also assist in defining more accurate test methodology to conduct brake tests. Uncontrolled sources of variability included in study are variation of driver, surface temperature & vehicle, while controlled sources of variability included in study are applied brake force, tyre construction, inflation pressure & test load. The concerned parametric variations have been studied on stand-alone basis as well as combination of more than a single factor. It has been observed that braking in panic condition with higher brake force may not yield the best brake performance and each vehicle and brake system operate ideally in a specific brake force range. As studied previously [2], a rise in surface temperature causes deteriorated braking performance while it is found to improve with increasing inflation pressure which is contrary to published data [2] [3] and needs to be further investigated. Sensitivity to different tread compounds has also been captured. Braking performance is found to be more sensitive to driver style than the average or maximum pedal brake force being applied. Skid Trailer and Flat track machine tests have also been conducted to validate tyre test data with larger control on test parameters and inputs. This also provides useful data to compare braking performance of a tyre on stand-alone basis other than the tyre-vehicle assembly.