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# How do you calculate the differential gear ratio?

## How do you calculate the differential gear ratio?

Enter the maximum potential safe engine RPM. Enter the tire size diameter and the target vehicle speed in MPH. Click “Calculate Gear Ratio”. The value will be returned in estimated differential gear ratio, based on the entered values…

## What’s the rear end gear ratio in a GMC?

General Motors rear end differentials are referred to by the diameter of the ring gear, i.e. 7.5 inch, 8.5 inch, 10.5 inch. Our experts will help you find the correct ring and pinion set for your particular application.

Why do I need to lower my gear ratio?

The 3.07:1 differential with the close-ratio gearbox raises second gear so much that the engine will be “bogging” coming out of the slowest turns—and you don’t want to downshift into first. This gives us another reason to lower the 3.07:1 differential ratio. (Remember that lowering the ratio produces a higher number.)

### Why do you need the right axle ratio for a GMC Truck?

Ordering the right axle ratio can further help tailor a new GMC truck or SUV to your particular needs. Axles and differentials contain gearing that allow power to be transferred from your engine and driveline to the wheels. The engine and transmission spin a driveshaft, which is coupled to a stout pinion gear within the axle.

### What is the ratio of gears in the rear end differential?

This is the ratio of gears in the rearend (differential) that you may have heard of in the numerical terms 2.73 to one, 3.23 to one, 3.55 to one, 3.73 to one, and 4.10 to one (commonly written in the following manner 3.23:1 with a colon).

What does a gear ratio of 4.56 mean?

It is controlled by the number of teeth on the ring vs. the pinion. A ratio of 4.56 means that as the axle turns one whole circle the driveshaft turns 4.56 circles. The higher the number the lower the ratio becomes. The correct axle gear ratio is important for drivability and economy.

The 3.07:1 differential with the close-ratio gearbox raises second gear so much that the engine will be “bogging” coming out of the slowest turns—and you don’t want to downshift into first. This gives us another reason to lower the 3.07:1 differential ratio. (Remember that lowering the ratio produces a higher number.)

#### How is axle ratio related to transmission ratio?

Your axle ratio, transmission ratios, and even tire diameter all factor in, so be sure to look at the big picture. The axle ratio is derived from dividing the number of teeth on the ring gear by the number of teeth on the pinion gear. For a 3.73 ratio, there may be 41 teeth on the ring gear and 11 on the pinion for 3.72.

#### Where can I find West Coast differentials gear ratios?

Find all of the gear ratios available for your vehicle in our Application Guides or call our staff of differential experts at (800) 510-0950 for LIVE help. West Coast Differentials stocks a huge inventory of OEM and Aftermarket Ring & Pinion Gear sets and orders placed before 4 PM Pacific Standard time usually ship the SAME DAY!

How is tire size and axle gear ratio related?

This page is a Differential Gear Ratio Chart for comparing tire size to axle gear ratio and the combined effect on power and fuel economy.

## What should the differential gear ratio be on a new car?

Once all this information is known use the following formula to get the accurate differential gear ratio for the larger tires: The rpm is 2806 at 105 km/h (65 mph), the current tires are 29 inch, the factory ratio is 3.73 and the new size upgraded tires are 33 inch.

## What was the rear axle gear ratio in 1982?

It was common to find 3.08 and lower rear axle gear ratios in 1982 and older vehicles. 1984 Corvette Crossfires took full advantage of this technology with 3.07-3.31 rear axle gear ratios and an engine that ran out of power at 4000 rpm due to the restrictive intake manifold.

How to calculate ring and pinion gear ratio?

You can try various combinations to come up with an appropriate combination of ring and pinion gear ratio and tire diameter for your vehicle. The RPM calculator should be used as a guideline for comparative purposes only. Your vehicle will probably run at different RPM’s than those you calculate.

### How to find the right gear ratio for your tires?

Gear Ratio Calculator – Choose the right Gears for your Tires! Gear Ratio Calculator – Choose the right Gears for your Tires! When you change your tire size you need to make sure you have the right gearing to get optimal fuel economy and power. A good way to calculate this is to multiply .12 by your Jeeps tire diameter (Example: .12 X 38″ = 4.56).

Ruth Doyle