Gear Ratio & Top Speed Calculator
Calculate vehicle speed at redline for each gear, or find RPM at a target speed.
Load Common Transmission
Gear Ratios
Vehicle Setup
RPM at Target Speed
Understanding Gear Ratios
The gear ratio determines how many times the input shaft spins for each rotation of the output shaft. A higher ratio (like 3.5:1 in 1st gear) means more torque multiplication but less speed.
The final drive ratio (also called diff ratio or ring & pinion) provides additional multiplication. Changing it affects all gears equally.
Shorter (numerically higher) final drive ratios improve acceleration but reduce top speed and fuel economy. Taller (numerically lower) ratios do the opposite.
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