This is a JavaScript page that calculates what the speed of your vehicle will be for a given motor rpm, gear ratio, and wheel diameter. We also use it to work backwards to find the RPM needed if we want to use the speed limiting function of the Pro-160 / 360 to set a maximum speed.
Sorry, but without JavaScript enabled, you won’t be able to use this calculator.
You will need to enter the following data:
- Motor speed, at the full battery voltage you intend to use, this is usually on the name plate or specification of the motor.
- Reduction gear ratio. This is the total reduction ratio between the motor shaft and the driving wheel. For instance, a chain drive with 10 teeth on the motor sprocket and 80 teeth on the wheel sprocket will have a ratio of 8.
- Road wheel diameter. This is the actual diameter of the wheel, that is in contact with the road. You can measure the diameter in millimetres, centimetres or inches, but you will need to tell the calculator which.
When you’ve entered all these figures, click on the Compute button and the calculator will show your speed in Km/Hr and in Miles/Hr.
If you’ve entered any parameter and the calculator can’t make it a number, you will get an error message NaN.
If you get a result 0 or Infinity – you’ve left an input blank.
We also have a motor current calculator.