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Gear Ratio Calculator - Final Drive & RPM
Free gear ratio calculator. Calculate axle ratio, final drive, and engine RPM at speed. Essential for gear swaps and tuning.
Gear Ratio Calculator
Calculate gear ratios and RPM
Gear Ratios
Enter your values to see results
and click the "Calculate" button
Gear Ratio Calculator
Calculate axle ratio and engine RPM at cruising speeds. Essential when changing differential gears or tire sizes.
Gear Ratio Formulas
Axle Ratio = Ring Teeth / Pinion Teeth | RPM = (Speed × Ratio × 336) / Tire Diameter
Higher ratio = more acceleration, higher RPM, lower top speed. Lower ratio = better fuel economy, lower RPM.
Frequently Asked Questions
What ratio is best for fuel economy?
Lower ratios (2.73, 3.08) = lower cruising RPM = better MPG. Higher ratios (3.73, 4.10) = better acceleration.
How do tire size and gear ratio interact?
Larger tires = lower effective ratio. If you increase tire size, you may need higher gears to maintain performance.
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