RMHC Speed Calculator

• the outside tire (tyre) diameter in inches
• the rear axle (differential) gear ratio
• the gear ratio of a selected gear in your gearbox
• the overdrive ratio (in Healeys this is either 22% or 28% - or 0 if you don't have one)
• the RPM that you want to determine the speed for

Select the "Compute" button and the speed will automatically be calculated. You can enter additional values in the other rows to get additional speeds. Hitting the "Reset" button in that row clears the row.