TRX/ATC 250 Big Red Billet Primary Gear Reduction

20% IN STOCK 40% IN PROCESS  60% IN PROCESS These are our American-made billet gear reduction offerings for the 85'-88' ATC250ES Big Red, ATC250SX and TRX250. Our gears are CNC machined from raw billet material to make our proprietary sizes of 20% 40% 60% and 75% reduction. Requires gear indicator cup delete and neutral wire mod. We offer stiffer clutch springs for these reductions in the "TRX/ATC250" and "Parts" sections of the site listed as "TRX Springs". The stiffer springs can be ran with any size reduction but are necessary for the 60% and 75% to prevent clutch slippage. There is a sizing chart tab on the home page with reduction per tire size recommendations. **Most if not all 85' models use a smaller diameter crankshaft, verify engine year by visually checking or measuring crank diameter and make a note when ordering. The small (85) crank is 24mm diameter and 86up is 27mm. You can also use the engine serial # to verify year but we are not positive that all 85's use the smaller