Abstract
Tire deflection is a key parameter and many equations have been developed based on it to evaluate the tractive performance of bias-ply and radial-ply tires. As deflections for a given tire size, inflation pressure and vertical load are significantly different between bias-ply and radial-ply tires, this study was conducted to predict deflection (d) of radial-ply tire based on section width (b), overall unloaded diameter (d), inflation pressure (P) and vertical load (W). For this purpose, deflection of four radial-ply tires with different section width and/or overall unloaded diameter were measured at five levels of inflation pressure and five levels of vertical load. Results of deflection measurement for radial-ply tires No. 1, 2 and 3 were utilized to determine multiple variables regression model and results of deflection measurement for radial-ply tire No. 4 were used to verify selected model. The paired samples t-test results showed that the difference between the deflection values predicted by model and measured by test apparatus were not statistically significant and to predict deflection of radial-ply tire based on section width, overall unloaded diameter, inflation pressure and vertical 2 load the multiple variables regression model = 75.67 + 0.104 b- 0.107 d- 0.758 P + 3.519 W with R = 0.986 can be strongly recommended