Gear Tooth Ratio Calculator

Gear Tooth Ratio:

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.

Formula:

[ 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

Bigger tires aren't the only reason to change gears, many truck owners swap gears for better mileage.
If your vehicle is a 4x4, you will need to change the gears in both front and rear axles.
Most front axles require reverse cut gears because front driveshafts typically spin the other way.
Front and rear gears can be different by 1% on road and 2% off-road without impacting performance.

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