The drive axle Sumitomo ST918 tire is engineered for rough metro environments. Its all-weather tread design features radical shoulder ribs that stabilize tread. During dry or wet maneuvers, the center island tread elements enhance traction while special reinforcing bridges improve stability and minimize wear. The multi-phase shift tread design ensures quieter rides and the steel casing improves tire stability. In wet conditions, the grooves disperse water to improve safety.