Gear Ratio Calculator

Bigger tires change your effective gearing — you lose power, your speedometer reads wrong, and your engine works harder at speed. Enter your current setup and tire size to find the ring & pinion ratio that restores it.

This calculates the ratio needed to restore your original effective gearing after a tire size change — the standard starting-point formula gear manufacturers use (New Ratio = Old Ratio × New Diameter ÷ Old Diameter), rounded to the nearest commonly-manufactured ratio. For very large or heavy tire setups (37"+, armor, winches), many installers step one ratio higher for extra power. Exact ring & pinion part numbers depend on your specific axle housing and carrier — contact us to confirm before ordering.