Hello everybody! I'm trying to write a car simulation but I'm having problems with precisely calculating the acceleration / velocity of the car's wheel. Currently the simulation works as if the Car was lifted in the air, so there is no load (vertical force) on the Wheel. What I have so far: - the applied torque (engine torque multiplied with appropriate values) - mass moment of inertia of the wheel Now I would like to take into account the weight Load on the Wheel. How do I do this? Currently the wheel spins up pretty fast even in 5th gear (well not at low RPM, but once the engine and axle are rotating together), but in reality I know it should be accelerating slower at high speeds - but it accelerates at the same speed as in 1st gear. I assume this is normal for no load on the wheel (though I might be wrong!!). Any help would be appreciated! :) Also this is my first post and this is not a homework assignment.