Performance of Tread Compounds in Various Tire Constructions

Abstract

Abstract There are now three major types of construction used in passenger car tires—cross-ply (or bias), belted cross-ply, and radial. The same rubber compounds and tread designs may not always provide optimum performance in these but it was considered of interest and importance to compare the relative performance of several typical tread compounds on each type of tire. Four tread compounds were applied as retreads to four tires of each type. These were road tested over a highway route which included some rapid cornering. Two polymer systems were employed: 1. a low vinyl, 85/15 butadiene/styrene, oil-extended, solution copolymer and 2. a 40/60 blend of high-cis polybutadiene/SBR 1712. These were reinforced with N330 (HAF) and N339 type carbon blacks. Some other tire tests were also available for supporting evidence. The solution copolymer gave 8 to 12% better resistance to abrasion than the polybutadiene/SBR blend. The N339 carbon black was 10 to 15% better in wear resistance than N330 black and the best combination was 23% improved over the poorest. These relationships were affected very little by the type of tire construction and indicate that treadwear data on compounds in one type of tire may be useful to predict performance in another. Results also indicate that treads of equal composition will provide a mileage ratio of approximately 1 to 1.5 to 2 or 2.5 on cross-ply, belted cross-ply, and radial tires, respectively.