Before finalizing your axle diameter choices, please consider the following: 1) Review the information under the “Choose Your Axle Diameter” tab above (or click here) to get an idea of what the different axle diameter combinations will offer in terms of performance, and what you can expect from them. 2) Consider that; the wider the thickness gap (or diameter difference) between the left & right rear axles, the more throttle turn you will have on corner exit. 3) Every Strange Oval axle is made to twist, you will gain some forward drive regardless of what axle diameter you may choose, all of which are thinner than your normal standard diameter axles….There is no wrong choice! Dirt Modified – Axle Diameter Quick Reference Guide: UMP, USMTS & Renegade Axle Diameter Range: LR:1.100” , 1.115” , 1.130” RR:1.115”, 1.130”, 1.145”, 1.165” WISSOTA Modified Axles: (SAME DIAMETER on both LR & RR required by rule) LR:1.130”, 1.145” RR:1.130”, 1.145” ISRA B-Mod Axle Diameter Range: (gun-drilled axles are allowed) LR:1.080”, 1.100”, 1.115” RR:1.080”, 1.100”, 1.115”, 1.130”