The gear ratio of your truck’s ring and pinion plays a part in determining how fast you get up to speed, what that maximum speed is, and your fuel economy. Normally your OEM gear ratio is intended to provide a good balance between economy, acceleration, and top speed. By changing your gear ratio or “re-gearing” your truck, you can sacrifice some performance in one area for gains in others. Generally speaking, by moving to a numerically higher “short gear”, you’ll improve your truck’s acceleration at the expense of some top speed. To help you understand this process, some key terms are important to understand.
Ring and Pinion: These gears transfer the rotation of your truck’s driveshaft(s) to your wheels. They are housed inside of a fluid-filled differential gear box. Two-wheel drive trucks only have a rear differential, while 4x4 trucks will have a front differential used when four-wheel drive is engaged.
Gear Ratio: This refers to the number of times the pinion must turn to rotate the ring gearonce. So when you see a number like 4.10:1, the driveshaft and pinion must rotate a little more than four times in order for the ring gear to rotate your wheels once.
Short Gears: A ring and pinion with a numerically high gear ratio is referred to as a short gear.
Tall Gears: A ring and pinion with a numerically low gear ratio is referred to as a tall gear.
A typical ring and pinion.
Let’s take a look at two common gear ratios used by Chevrolet trucks: 3.23:1 and 3.42:1.
The first ratio means that the driveshaft needs to rotate 3.23 times to make the wheels rotate once. The numerically higher 3.42 gear ratio means the pinion has to rotate more to move the truck, but with greater torque applied to the wheels. All other things being equal, the 3.23 truck will have better mileage and perhaps a higher overall top speed, while the 3.42 truck will suffer a bit on mileage but will accelerate more quickly and have more torque available at lower RPMs. Therefore, tall gears offer higher top speeds and better mileage, especially on highways and interstates, while short gears offer more torque to get the vehicle moving, which is crucial if you’re towing or hauling. It’s not uncommon to use a short gear in pickup trucks to improve the heavy vehicle’s acceleration and towing capabilities.
If you have questions about finding a new ring and pinion for your truck, chat or call our product experts.