Javascript Gearing Calculator
Primary Gear Front Sprocket   
Rear Sprocket Rear Wheel Dia

1 Gear MPH
2 Gear MPH
3 Gear MPH
4 Gear MPH
5 Gear MPH
6 Gear MPH


Default values are for a Yamaha Blaster.

The Blaster doesnt have a rev limiter, but in stockish form you probably wont go more than 8500 rpm. Ive set the limit to 8500 because that seems to be what most guys agree on as a believable max RPM on a stockish engine. Also because the value given at ~60mph for top speed of a stock Blaster seems to correspond to what Yamaha says the Blaster top speed is. If you have porting, etc performed you can probably get above 9000 out of it. This is just guestimation on the RPM/Top speed front, so this calculator is to be used for comparative purposes such as tire sizing changes, sprocket changes and relation of current configuration vs the desired configuration

Wheel diameter can vary subject to tyre choice. Measure roll circ and use C=Pi times D to calculate, where Pi is 22/7

To return the script default values use refresh in your browser plus the control key.