12:60 Chain Drive for Big Wheel OEM gear ratio Kit #35 Chain Drive Kit 12:60 Replaces: 1000-5M-15 belt 1000-5M-18 belt 1000-5M-20 belt #35 ansi roller chain kit for: Chuweng Raser big wheel with 145/70-6 size tires and 6 inch wheels. Also FITS Xcooter Thunder, Saloor Big Wheel, Sonic Big Wheel, THS Big Wheel, Desert Storm Big wheel, Steeple Big Wheel, PanthR Big Wheel, AND OTHER MODELS using 145/70-6 rear tire. Kit includes #35 ansi chain & master link (This chain is 128 pins including master link) a 12 tooth #35 shaft sprocket and a 60 tooth #35 wheel sprocket, one 1/8 roll pin and one 1/8 inch drill bit. The factory sprocket on the shaft is 20 tooth 5m and the factory wheel sprocket is a 102 tooth 5m belt drive sprocket. The factory gearing is 1:5.1 This 12:60 chain drive kit is a 1:5 ratio For top speed chain drive kit on a "Big Wheel Scooter" see our 12:52 kit which is a gear ratio of 1:4.3 and a Chain drive kit for big wheel scooters only, see exclusion below. This 52 tooth sprocket is the same as oem sprocket for "The Rocky" but the shaft sprocket is totally different so this is not for "Cobra Extreme" or "The Rocky"