Universal Regear Calculator
Enter your current setup and desired modifications to get instant gear recommendations.
This calculator estimates the axle gear ratio that best restores your vehicle's factory performance after a tire-size change. It applies to solid-axle and fixed-ring-and-pionion drivetrains common to light trucks and SUVs (Ford F-Series, Chevy Silverado, GMC Sierra, Ram, Jeep Wrangler/ Gladiator, Toyota Tacoma/Tundra, and Hummer). It is notintended for front-wheel-drive or transaxle-based passenger cars, where final-drive changes are handled at the transmission rather than the axle.
Results assume a direct-drive high gear (1:1) or a representative overdrive and use the standard RPM formula RPM = (MPH × Ratio × 336) / Tire Diameter. Recommended ratios are snapped to the closest commonly available aftermarket gear set, and the drivability score factors in tire size, driving style, and engine modification level. All figures are planning estimates — always confirm axle tag codes, transmission ratios, and VIN-specific final-drive values from OEM service data before purchasing or installing parts.