The “**Speedometer Gear Calculator**” is a handy tool designed to assist you in determining the appropriate gear teeth for your speedometer.

## Speedometer Gear Calculator Tool

## How to Calculate Speedometer Gear Teeth

To calculate the speedometer gear teeth, you would typically need the following information:

**Tire Diameter:**Measure the diameter of the tires on your vehicle in inches. This measurement represents the height of the tire from the ground to the top of the tire.**Axle Ratio:**The axle ratio refers to the number of revolutions the driveshaft makes compared to the axle or wheel revolutions. It is usually denoted as a ratio (e.g., 3.73:1).**Desired Speedometer Accuracy:**Determine the level of accuracy you want for your speedometer. This is typically expressed as a percentage. For example, if you want the speedometer to be accurate within 2%, the desired accuracy would be 2.

The formula to calculate the speedometer gear teeth is:

Speedometer Gear Teeth = (Drive Teeth * Axle Ratio * 63360) / (Tire Diameter * Desired Accuracy)

Where:

- Drive Teeth: Number of teeth on the drive gear (typically located on the transmission output shaft or a sensor).
- Axle Ratio: The ratio of the number of teeth on the ring gear to the pinion gear in the differential.
- 63360: Conversion factor to convert inches to miles (12 inches in a foot, 5280 feet in a mile).
- Tire Diameter: The measured diameter of the tire in inches.
- Desired Accuracy: The desired accuracy of the speedometer reading as a percentage.

By plugging in the values for drive teeth, axle ratio, tire diameter, and desired accuracy into the formula, you can calculate the appropriate number of teeth for the speedometer gear.