How to calculate speedometer gear ratio?

How to calculate speedometer gear ratio?

How to calculate the number of teeth on speedometer drive gear?

1. Divide the number 20168 by the diameter of the tire to find the number of revolutions per mile.
2. Multiply the revolutions with axle ratio, A .
3. Divide the product with 1001 .
4. Multiply the gear ratio with the number of teeth on the driven gear, N .

What speedometer drive gear do I need?

To determine your tires true diameter in relation to determining what speedometer gears you need, measure from the ground up to the center of the axle then multiply by two. The actual run out of the tire can be as much as 2 to 3 inches less than what the circumference of the tire measures.

How far off is my speedometer with bigger tires?

You might ask: do bigger tires make your speedometer faster? The answer is no. Tire size and speedometer accuracy are directly linked to each other. Up-sizing, or installing a taller tire, will lead to a speedometer reading that is slower than your actual speed.

How do you calibrate an electronic speedometer?

To calibrate your electronic speedometer: With the power off, push and hold the calibration button (trip/reset button when equipped). While holding the button, start the vehicle and continue to hold the button until the pointer sweeps to full scale and stays at full scale. You may now release the button.

What is speedometer ratio?

Most automotive speedometers have a 1:1 ratio. This means the gauge is calibrated to 1 mile for every 1,000 revolutions. If you change tire size or rear-end gear ratio, your speed and odometer will be off.

What is Speedo ratio?

Most automotive speedometers have a 1:1 ratio. This means the gauge is calibrated to 1 mile for every 1,000 revolutions. If you change tire size or rear-end gear ratio, your speed and odometer will be off. To fix the issue, different speedo gears are available.

How do I calibrate my speedometer for bigger tires?

Press and hold the calibration button located on the speedometer, start the vehicle, and then release the button. Press that button again and then take the test drive. Once you have driven the distance needed, press the button once more and the speedometer will calibrate itself to accommodate the new tire size.