Originally Posted by justpoet

A few ways to get an approximate idea of speed, though certainly not the same for torque. This roughly equates to the number of pinion teeth going past a location over a period of time, but again is not really an accurate measure specifically. I also don't suggest you try to just gear to compensate, as you want a motor/battery combination designed for the application.

16.8x1900x18 = 574560
12.6x1900x? = 574560 24t pinion would get you here
12.6x2200x? = 574560 20-21t pinion would be around this range
12.6x2650x? = 574560 17t pinion would be very close

Of the options you mentioned in later posts, I would choose the 2650 and start with a 17t, going up or down from there based on torque/temps.

Alternatively, become an eBuggy lite and put a good SC motor and stick pack in. You'll most likely be below weight then too. In all cases, just be sure to vent the body well and keep things cool with your drivetrain well maintained and moving freely. The lower the voltage goes, the more important that becomes to keep heat in check.