Description 8" wheel with 65A durometer urethane rubber tread material Body material: Black polycarbonate Coefficient of friction: 1.0 static (on tight pile carpet) Bore: 0.95'' diameter through hole The 8" FIRST Rubber Treaded Wheel has a six holes (0.17 inch diameter) bolt pattern on a 1.875'' diameter bolt circle. View more Dimensions Diameter: 8'' Bore: 0.95'' diameter through hole, with two 1.125 inch diameter bearing pockets Weight: 0.62 pound Links ZIP File