The ST528 has stone ejectors which protects the casing from damage in the base of the groove. Its thick curbing ribs help shield the casing from side wall damage and the extra thick layer of under tread rubber protects the belt package. Its rust inhibitor compounds coat all interior steel belts and body ply components. The Sumitomo four steel belt casing construction resists punctures, increases vehicle stability, and contributes to more retread cycles. It has a deeper tread depth which increases time in service and provides more traction at all wheel positions. Its application specific tread compounds resist tread chipping in high-scuff on and off road applications.