Subscribe to a magazine

Gear Ratio

Back to article View Gallery
11 of 15
Gear ratio is the ratio of pinion teeth to ring gear teeth. For example, this Superior Gear Dana 44 gearset has a 4.88:1 ratio. There are 8 pinion teeth and 39 ring gear teeth; 39 divided by 8 is 4.875, rounded off to 4.88. For every turn of the ring gear, the pinion turns 4.88 times. This means one rotation of the ring gear contains 4.88 times the power applied to turn the driveshaft just once. A higher gear ratio number is often referred to as a lower gear in the same way First gear in your transmission is a lower gear with a higher torque multiplying ratio. These lower gears (higher numerically, such as 7.17) are often used as you increase tire size and are considered off-road gears because they help multiply torque. Higher gears (lower numerically, such as 3.73) are often referred to as highway gears because they reduce engine rotation while running at high speeds.

Advertisement