This report describes two experiments carried out to investigate the influence of certain features of tread pattern design, on the skid resistance of tyres. Measurements were made of peak and locked wheel braking force coefficients, on several wet surfaces at speeds between 20 and 105 mile/h, using a front wheel braking technique. In the first experiment four tyres were used having respectively 5, 7, 9 and 13 straight cut ribs and having the same overall tread area. The results showed the differences between these tyres were small, except on the most polished surface, where the 5-rib tyre gave a larger decrease of coefficient with increasing speed. In the second experiment, the rib width was held constant, and the groove width varied. Initially, six tyres were tested; a 2 1/2 in. wide smooth tyre, and six ribbed tyres having five 1/2 in. ribs and a range of groove widths. The results showed that no appreciable increase in coefficient was obtained when the groove width exceeded a critical value. The optimum value of groove to rib width ratio for these tyres was 0.4. The results of the experiments are discussed in terms of water drainage and lubrication effects in the tyre - road contact region. (Author)
Experiments on Tyre Tread Patterns
1967
28 pages
Report
Keine Angabe
Englisch
Road Transportation , Tires , Friction , Water , Lubrication , Pavements , Vehicle brakes , Design , Velocity , Experimental data , Great Britain , Tire treads , Graphs(Charts)