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Gear Tooth Ratio Calculator

Enter the number of teeth found on your ring gear as well as your pinion gear in the boxes below to calculate their combined ring and pinion gear ratio.

Ring Gear Teeth:
Pinion Gear Teeth:
Gear Ratio:

(Confirm your answer with the standard gear ratios listed below.)

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Gear Ratio Calculation Basics

Your axle gear ratio determines how many times your driveshaft rotates for every full tire rotation. For example, a 3.73 gear ratio requires 3.73 driveshaft rotations to turn your tires once around. You should be able to find your gear ratio listed on the axle tag, however, if that has gone missing, you can simply count the number of teeth on each gear and divide the number of ring gear teeth by the number of pinion gear teeth.

[ Ring Gear Teeth / Pinion Gear Teeth ] = [ 41 / 11 ] = [ 3.73 ]

Popular OEM and Aftermarket Gear Ratios

The following table contains a list of common aftermarket gear ratios. Keep in mind that in some applications the gear ratios might not calculate exactly, as is the case with 4.09, 4.10, and 4.11 gears and 4.30 and 4.31 gears.

2.47 3.54-3.56 4.50 5.50
2.84 3.60 4.56 5.57
2.91 3.64 4.63 5.67
3.00 3.70 4.71 5.75
3.07 3.75 4.78 5.83
3.08 3.82 4.86 6.00
3.10 3.89 5.00 6.14
3.15 4.00 5.11 6.20
3.25 4.09-4.11 5.13 6.33
3.33 4.30 5.25 6.43
3.40 4.33 5.29 6.50
3.45 4.40 5.33 6.86
3.50 4.44 5.43

For a complete list of gears available for your vehicle, visit the Filthy Motorsports Drivetrain Shop.

Helpful Gear Changing Tips

This gear tooth ratio calculator is ©Copyright - Please provide a link back to this page when copying.
Data is accurate to the best of our knowledge and is offered as-is with no guarantee.

More Gear and Axle Guides:

Differential Locker Comparison - A detailed comparison of popular differentials and lockers.
Ring and Pinion Setup Specs - Ring and pinion gear setup specifications for popular axles.
Ring and Pinion Gear Tooth Patterns - Gear tooth pattern setup and adjustement instructions.
Gear Ratio Finder - Find the ideal axle gear ratio for your new larger or smaller tires.
Ring and Pinion Ratio Variations - An explanation of why some ring and pinion gear ratios vary.
Thick Gears and Carrier Breaks - Thick ring and pinion gears and differential carrier breaks explained.