1986 Chevrolet Camaro z28

[BLACK CAT]

2. Series of Carrier

To determine which gear sizes are compatible with your current rear-end setup, you need to know the series of differential carrier, especially when dealing with GM and Dana applications. 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. 

If you don’t know your current gear ratio, the easiest way to calculate the ratio is by using the following formula: 

Number of ring gear teeth/number of pinion gear teeth

Example: 39 ring/11 gear teeth=3.54 ratio

Most gear manufacturers will give a range listing of what gear ratios go with each series of carrier. In general, the carrier series follow these guidelines:

• 2-Series Carrier: 2.73-Lower Gear Ratio
  
• 3-Series Carrier: 3.08-3.90 Gear Ratio
  
• 4-Series Carrier: 4.10-Up 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 (pictured at right).  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. For example, never use a  2-Series carrier with 4-Series gear ratio.  

3. Vehicle Purpose

With your rear-end type and carrier in mind, you can now zero in on your desired gear ratio. Ask yourself: What is the purpose of my vehicle? This information will help determine a general range for your optimum gear ratio. Here are some general guidelines:

• Daily Driver: 2.55-3.23 Gear Ratio
  
• Street/Strip: 3.42-3.90 Gear Ratio
  
• Race: 4.10-Up Gear Ratio