This is a very simple calculator which takes dimensions of the model wheelÂ and the real machine top speedÂ to calculate the motor rpm Â you would need to achieve the scaled speed with your 1:32 scaleÂ model.

It works by usingÂ the wheel diameter to calculate the circumference of the wheel whichÂ is the distance travelled in one revolution of the wheel.Â The top speed on the real 1:1 scale machine is divided by 32 to giveÂ the 1:32 scale equivalent of the the speed.Â This value is then divided by 60 to give km/min and multiplied byÂ 1000000 to give mm/min. Dividing this value by the circumference of the wheel gives us the rpm of the wheel required to achieve that speed which is usually the rpm of the gearÂ motor because the axle is usually the output of the gear motor.