Pedal Ratio Calculator

This calculator is intended to calculate a lever ratio based on a desired system pressure and pressure on the lever. You can read more about system pressure and master cylinder selection on the Brake Tech page.
For example, if a driver is strong enough to press with 100 lbs. of force on a hand brake, and 1200 psi. is specified as the system pressure, this calculator will give the ratio required for various master cylinder sizes.
Yellow boxes should be changed to suit your own application:
Enter the Desired hand lever force: Enter the desired foot pedal force:

Master Cylinder Bore Size Desired System Pressure Force Required on Rod Hand Lever Ratio Pedal Lever Ratio
0.75" PSI LBS : 1 : 1
0.875"  PSI LBS : 1 : 1
1.00" PSI LBS : 1 : 1
1.125" PSI LBS : 1 : 1
" (custom)  PSI LBS : 1 : 1




Gear ratio and RPM Calculator

Use this calculator to estimate various aspects of your performance. The defaults show suggested values.

If you would like to find a value other than speed, fill in information for all the boxes and clear the valu in box you would like an answer for. For example if you want to calculate RPM at a known speed, clear the RPM box or set it to 0.
Description: English Input:   Metric Input:
Tire Diameter: Inches MM 
Wheel Rollout:  Inches  MM 
Engine RPM: RPM  
Final Drive Ratio:  
Gear Ratio:  
Torque Converter Slip (%) %  
Speed:   MPH   KPH





Tire Size Calculator

Enter the tire information found on the sidewall of your tire. For example a tire that is marked 205/65 R16 has a tread width of 205, a profile of 65, and a wheel size of 16". This will give an approximation of your tire diameter and rollout. Due to variations in tire construction and wheel widths this is not an exact number.

Enter Tread Width: Calculated Diameter (in) IN
Enter Profile: Calculated Diameter (mm) MM
Enter Wheel Diameter: (IN) Calculated Width (in) IN
Enter Wheel Diameter: (MM) Calculated Rollout (in) IN
    Calculated Rollout (mm) MM



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