Scale Tank rebuild, what motors to use?

[BrianG]

If you keep the stock gear box, you're gonna have to either calculate the various ratios, or simply turn the input and count how many times the input has to be turned to get one output turn. Mutiply this by total motor speed, then multiply by sprocket circumference. Divide that whole number by 1056 to get speed in mph.

If you want to go chain drive, you can work backwards. Take your desired speed in mph, multiply by 1056, divide by sprocket circumference, then divide by whatever radio created by the chain drive setup. This number will be your total motor speed needed to drive at the speed you want. Divide that by battery voltage to get the kv you want. Since a single chain drive setup will be pretty low, you're probably gonna want to go with a slower outrunner setup.

BTW: You might want to think about how fast you want to go. Those tank treads may not like to spin fast enough to hit ~20mph. You know what a ballooning tires does when it breaks; imagine that happening to a tank tread! :036:

When you get closer to deciding how you want to gear this, post back here and I'll show you how you can use my R/C calculator to do the math for you.