Size Ply Rating Tread Depth (mm) ST175/80R13 6 7.6 ST205/75R14 6 7.6 ST215/75R14 6 7.6 ST205/75R15 6 7.6 ST205/75R15 8 7.6 ST225/75R15 8 7.6 ST225/75R15 10 7.6 ST235/80R16 10 7.8