Axle Ratio Calculator
Final drive axle ratio or engine rpm at a given speed from tyre size and gearing.
Compare Your Options And Get Clear Answers
Final drive axle ratio or engine rpm at a given speed from tyre size and gearing.
Axle Ratio Estimator
Enter your numbers below for an instant estimate.
How It Works
Key concepts behind this calculator
Enter Values
Fill in each field with your own numbers.
Calculate
Results update as you change the inputs.
Review
Read the breakdown and the explanation.
Adjust
Change values to compare scenarios.
Axle Quick Guide
Typical values for reference.
| rpm | mph | Tyre in | Axle ratio |
|---|---|---|---|
| 1800 | 65 | 29 | 3.19 : 1 |
| 2200 | 65 | 29 | 3.89 : 1 |
| 2600 | 65 | 29 | 4.60 : 1 |
| 3000 | 65 | 29 | 5.31 : 1 |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
Axle Ratio Calculator FAQ
Answers to common questions about this calculator.
How many times the driveshaft turns per wheel turn.
More acceleration and higher rpm at speed.
Axle ratio = rpm x tyre circumference / (mph x 1056 x gear ratio).
It is an estimate based on the inputs you enter. Check real quotes, labels or official guidance for important decisions.