How to Determine Ring Gear Size

There are a few things you need to know in order to determine ring gear size. The first is the number of teeth on the ring gear. The second is the pitch diameter of the ring gear, and the third is the center distance between the two shafts that the ring gear sits on.

All of these measurements must be made with great accuracy to ensure an accurate result.

  • Determine the size of the ring gear by measuring the diameter of the gear with a caliper or micrometer
  • The number of teeth on the ring gear can be determined by counting the number of spaces between each tooth
  • Once you have both the diameter and tooth count, you can determine the pitch circle diameter (PCD) of the ring gear using a simple formula: PCD = ( Number of teeth / 2 ) x Diameter 4
  • With the PCD known, you can now determine the Module or Circular Pitch (CP) using another simple formula: CP = PCD / Number of Teeth

How to measure ring gear & axle flange runout & ring gear backlask

Ring Gear Size by Vin

When it comes to ring gear size, there are a few things that you need to take into consideration. The first is the bore size of your engine, and the second is the stroke of your engine. The bore size will determine the maximum ring gear size that you can use, and the stroke will determine the minimum ring gear size that you can use.

The reason why bore size and stroke are important is because they affect how much torque your engine produces. The more torque your engine produces, the larger the ring gear needs to be in order to handle that torque. If you try to use a ring gear that is too small, it will simply spin on the crankshaft and not provide any power to your car.

The easiest way to figure out what ring gear size you need is to consult with a professional. They will be able to take into account all of the factors mentioned above and give you an accurate recommendation.

How to Determine Ring Gear Size


How Do I Know What Size Differential I Have?

Differential sizes are typically identified by the diameter of the ring gear, but can also be identified by the overall width or specific measurements. The most common diameters are 7.5″, 8.8″, 9.25″ and 10″. To determine the size of your differential, you will need to measure the distance between the innermost edge of one tire to the outermost edge of the other tire.

This measurement is called the “track width.” To get an accurate measurement, it is best to do this while the vehicle is on a level surface and with both tires inflated to their recommended PSI levels. Once you have this measurement, simply reference a chart that correlates track widths to differential sizes (see below).

Track Widths in Inches Differential Sizes 60-62.9” 7.5” 63-65.4” 8”

65.5-67” 8.8”* 67-68.6” 9” *For vehicles with a track width over 66 inches, it is recommended to use an 8.8” differential for improved stability

hope this helps!

How Do I Know What Size Rear Axle I Have?

If you’re not sure what size rear axle your car has, there are a few ways to find out. The most accurate way would be to consult your car’s owner’s manual. If you don’t have access to that, you can also look for the information online or in a service manual.

Another way to determine your rear axle size is by measuring the width of the axle tube. This can be done with a tape measure or ruler. Once you have the measurement, simply compare it to a chart of common rear axle sizes to find a match.

Finally, if all else fails, you can always take your car to a professional mechanic or auto body shop and they should be able to tell you what size rear axle you have.

What Do the Numbers on a Ring Gear Mean?

When you’re looking at a ring gear, the numbers represent the teeth on the gear. The higher the number, the more teeth there are. This is important because it determines how many rotations the gear makes in relation to another gear.

If one gear has twice as many teeth as another, it will make two full rotations for every one rotation of the other gear.

Is the Gear Ratio Stamped on Ring?

The gear ratio is the number of teeth on the ring gear divided by the number of teeth on the pinion gear. The vast majority of ring gears have stamped on them, making it easy to determine the ratio. However, there are a few exceptions where this isn’t the case.

In these instances, you can usually find the ratio by counting the teeth on both gears.


If you’re looking to determine ring gear size, there are a few things you’ll need to measure. First, you’ll need to find the pitch diameter of the ring gear. This can be done by measuring the distance between two adjacent teeth and dividing by two.

Next, you’ll need to measure the tooth width of the ring gear. To do this, simply measure the width of one tooth. Finally, you’ll need to measure the circumference of the ring gear.

This is done by wrapping a tape measure around the outer edge of the ring gear and noting the measurement. Once you have these three measurements, you can plug them into a formula to determine ring gear size.

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