I'm modelling a car in a simulator for fun. The sim's method of acceleration is to apply a force in Newtons on a selected wheel. I've browsed a few topics and whilst some come close there doesn't seem to be any equations that takes into account geartrains. Also I'm fuzzy on the relationship between torque and rpm. Equations seem to use one and exclude the other. I know that higher gears reduce torque and increase RPM but they shouldn't cancel each other out. I have calculated the drag and rolling resistance in Newtons. I have the wheel radius, torque and RPM curves, the car's mass, the transmission gear and the differential/final drive gear ratios. The car is FWD. For simplicity, assume there is 1 gear ratio with a fixed rpm & torque output. F = ma, naturally. Here says we can get velocity using RPM https://en.wikipedia.org/wiki/Gear_train#Example_2 v = [(wheel rad * 2 * pi) * engine rpm]/(trans gear * drive gear) And looking at equations from here http://www.engineeringtoolbox.com/cars-power-torque-d_1784.html Force = [(Torque * gear ratio) * (Engine RPM / gear ratio) * efficency value]/(wheel radius * wheel RPM) which does actually give a reasonable value except gear ratio has no impact and it tries to divide by zero if the car is still.