Gear and Tire Calculator Plus

Easy and versatile tool to calculate many ratios of your drive train. Will calculate any ratio based on other fields. Handy for anyone wanting to re-gear their vehicles, change tire size, check rpm at a given speed (or speed at given rpm), etc.

Supports calculations based on preset transmission ratios. You may choose to select transmission ratio from a list of common transmissions (and respective gears).

Both standard and metric measurements are supported. Includes large diameter tires.

Calculates:
Tire sizes
Differential ratios
Transmission ratios
Engine RPM
Speed

Please contact me for any issues or feature requests (this includes transmission additions).