Gear ratio calculator for your Chevrolet

This will help you pick the right size tires, transmission and gear ratio combination for your classic

If you are looking for help with restoring or hot rodding your chevy classic a good place to go for help is Chevy Talk
my favorite forum is 1955-1957 ( Modified / pro street / show) forum.

Also check out for 55-57 Chevy's.

Enter your tire size (the diameter may vary slightly depending on the manufacture if in doubt use manufactures posted diameter)

Metric width Profile Rim diameter or enter the diameter of the tire below

Enter the rear tire diameter Or use the tire selector above

Effective tire diameter The tire diameter is less with a load (effective tire diameter = rim diameter + (tire sidewall x 0.94))

Pick your rear end gear ratio

Select your transmission
Click here for speedometer gear calculator

      Enter MPH Enter RPM
  Gear Ratio MPH the motor is at RPM the car is doing
  First RPM MPH
  Second RPM MPH
  Third RPM MPH
  Forth RPM MPH
  Fifth RPM MPH
  Sixth RPM MPH


I appreciate any input, if you see any mistakes or any thing you would like to see added please let me know.

Any comments or suggestions please email me