Observed speed gear ratio calculator

- Calculates overall gear ratio based on observed speed
- You can also calculate gear ratio based on tooth count

In addition to calculating the overall gear ratio, this information can be used to calculate either the transmission gear ratio or the differential ratio. The differential ratio is calculated from the transmission gear ratio, and the transmission gear ratio is calculated from the differential gear ratio.

Enter your engine speed, vehicle speed, and tire diameter. Calculate your overall gear ratio. You can also enter your transmission gear ratio and differential ratio and calculate each one from the other.