Gear and RPM Data

Tire Data
Final Gear Ratio: Tire Width in (mm):
RPM Limit:
Aspect Ratio:
RPM Max Power:
Rim Diameter (inch):

Tire Diameter:
Gears  Ratio Compound Tire dimensions (Calculated)
1st Side Wall Height (inch):
2nd Tire Width (inch):
3rd Tire Diameter (inch):
4th Tire Circumference (inch):
5th Revolutions per mile:
6th Revolutions per kilometer:

Shift Points, You can edit, copy and paste from the table below

Gear, Shift Point and Speed Calculator


This is a gear, speed and shift point calculator. Given a few bits of information on your drivetrain and tires it will computer shift points, max RPM. You can enter tire size by the standard profile numbers or by the tire diameter. Transmission gear selection can be from a list of some common gearboxes or enter the gear ratios (Up to 8 Speeds) manually. What's this for? Well you can use it to size your tires, rear axle ratio and determine shift points and all that. This is an EZ to use and web based shift point calculator!

The calculator outputs speed in each gear at 5mph intervals up to the maximum RPM. This is a text file for easy printing, just cut and paste into your word processor or text editor. It also computes charts for Gear Ratio Slope, RPM Gear Drop and a Shift Point Chart. Use this data to optimize your driving. Trying to figure out the optimum shift point, this is a good starting point.

These charts are interactive, you can zoom, and click on various parts of the chart to read data at the mouse. If you are on a phone your mileage may vary.

If you need help on what to fill in, click on the SAMPLE button it will show what it can do.

Double Click the Chart to reset the Chart back to normal zoom.

For Just the Simple Tire Size Calculator (TireCalc) Click HERE
GTSparkplugs Header
Click for Contact Page Click for Contact Page