In the seemingly endless search for efficient cars, enthusiasts often squander existing horsepower by using an improperly sized ring and pinion gear set. The right gear set will help transfer more power from the engine to the asphalt, improve engine acceleration or top-end speed. That’s why we here outline four key factors you’ll need to consider when choosing a ring and pinion gear set.

First, you need to tell your sales rep your rear-end type. There are two main types of rear-ends: conventional and banjo-style.

To determine which ring gear sizes are compatible with your current rear-end setup, you need to know the series of differential carrier. The carrier is the internal portion of the differential that is attached to the ring gear and is responsible for the distribution of power between wheels. Carriers are categorized by series, and the easiest way to determine differential carrier series is to simply look at your original gear ratio.

Typically, you’ll want your gear ratio to match the carrier series, but you may be able to use a higher gear ratio range with your current carrier by using a ring gear spacer. For example, a ring spacer may allow you to use a 3.08-3.90 gear ratio with a 2-Series carrier. However, you should never have more than a one series difference between the gear ratio and the carrier.

With your rear-end type and carrier in mind, you can now focus on your desired gear ratio. Ask yourself what is the purpose of your vehicle? This information will help determine a general range for your optimum gear ratio.

There are two basic styles of aftermarket automobile engine part gears: performance and pro. Performance gears are ideal for most street, strip, or off-road applications. They are made from hardened steel and are much more durable than stock. This allows them to handle higher torque applications.

Pro gears, like the ones offered by Strange Engineering, are for drag racing only. These gears are softer than a performance gear, so they can absorb the torque impact of the engine. However, the softer design of these gears will cause them to wear out more quickly than performance gears.