SIZE PR Tread Depth(mm) Standard Rim Load Index Speed Rate 12R22.5 18PR 21.5 9.00 152/149 J 8.25R16LT 16PR 17.5 6.50H 128/124 J 10.00R20 18PR 21 7.5 149/146 D 11.00R20 18PR 22.5 8.0 152/149 D 12.00R20 18PR 23.5 8.5 154/151 D