Equation for scale speed and gear ratios.

[Zephyranthes]

Here is the easiest way to figure scale speed.

Here is the equation for scale mph and explanations why you do them for people how really want to understand the equation.

If you want to know the gear ratios with a 7 tooth pinion gear (K.I.T. Racing pinion gear), here are the ratios. I recommend using this pinion gear because it visibly improves speed. Light green 8.25:1 gears with a 7 tooth pinion gear becomes 7.07:1. Orange 9.86:1 gears become 8.45:1. Light blue 12:1 gears become 10.2:1.

Take your motor rpm. (3.0 = 30,000)

Divide the motor rpm by the corresponding gearing you have. 56(8.25:1 gears), 48(8.25:1 gears with 7 tooth pinion), 67(9.86:1), 57(9.86:1 gears with 7 tooth pinion), 81(12:1 gears), 69(12:1 gears with 7 tooth pinion), 31(4.57:1 gears), 26(3.95:1 gears), or 23(3.43:1 gears). This number is the ratio between the motor rpm and feet per minute.

Multiply it by 60 for you want miles per HOUR

Multiply it again by 64 for the scale of a Bit is 1:64

Divide by 5,280 for there are 5,280 feet in a mile.

(If you are using all MicroSizer stuff, they have a chart for rpms, but if you have 3.0's, different gears and stuff, then use this formula.)

I calculated my car to go 457 scale mph with a 3.0 motor, 7 tooth pinion gear, and 8.25:1 speed gears.

Note: This is how fast your car would go without putting friction and weight and other uncontrolled variables into play.