Final Drive Ratio Calculator

Calculate the optimal final drive (ring & pinion) ratio for target speed, RPM, and tire size combinations.

Input Parameters

Results

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Final Drive Ratio
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Nearest Standard
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Actual RPM (Std)
RPM
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Speed @ 6000 RPM
mph
Note: Lower numerical ratios (2.73) favor fuel economy and highway cruising. Higher ratios (4.56) favor acceleration and towing. Common applications: 3.73 (performance), 3.08 (economy).

Reference

Wheel RPM = Speed × 5280 / (60 × Tire_circ) Overall Ratio = Target_RPM / Wheel_RPM Final Drive = Overall / Top_gear_ratio Standard ratios: 2.73, 3.08, 3.23, 3.42, 3.55, 3.73... Speed @ RPM = (RPM / Overall) × Tire_circ × 60 / 5280