[mototech77]

The JTR810 series fit the rear hub. Add a decimal for the tooth number. I installed a JTR810.38 and have the original 15t on the front. Initially I had the 17 and 38 installed but the gearing was too tall for the engine’s power band. I’m pretty happy with the 15/38 (2.533), but I may try to go just slightly taller with a 17/41 or 17/42 down the line.