[drive til its broke]

I am looking for a formula that can be used to calculate mph through rpm, gear ratios, and tire size. Any help is greatly appreciated.

 

[johnsongrass1]

Calculate RPM for Given Speed(MPH), Rear Gear Ratio, and Trans Gear Ratio

Calculate RPM for Given Speed(MPH), Rear Gear Ratio, and Trans Gear Ratio

purperformance.com

 

[RWENUTS]

I’ve got this in my favourites.

Tire Size, RPM, Speed, and Differential Ratio Calculator

Describes the process for converting a gasoline powered car to electric power

www.advanced-ev.com

 

['48 Austin]

The formula is:
Engine RPM = (MPH X Rear Gear Ratio X 336 X Trans Gear Ratio) / (Tire Dia inches X Torque Conv Efficiency)

Torque Conv Efficiency = 1 for manual clutch or lock up torque conv or about .95 for non lock up stock torque conv

 

[drive til its broke]

The formula is:
Engine RPM = (MPH X Rear Gear Ratio X 336 X Trans Gear Ratio) / (Tire Dia inches X Torque Conv Efficiency)

Torque Conv Efficiency = 1 for manual clutch or lock up torque conv or about .95 for non lock up stock torque conv

sweet thanks

 

[BuzzLOL]

Several handy calculators:

Andy's Auto Sport Calculators

www.andysautosport.com

 

[cerial]

This one has a drop down list of several transmission choices or you can enter your own transmission gear ratios.

http://www.grimmjeeper.com/gears.html

It gives a side by side comparison letting you easily see how changing the transmission, gear ratio, tire size etc will affect engine rpm. Also has room for transfer case and doubler/underdrive.