I am trying to create a vehicle simulation and get the vehicle to accelerate realistically by calculating the wheel speed in rad/sec. I know the torques and masses of a real world vehicle and I have video showing how fast it accelerates, so i want to recreate that. I have independently calculated air drag and gravitational forces, and I am calculating the force applied by:

force = wheelTorque/wheelRadius

force = force - dragForce + gravitationalForce (this is signed appropriately)

acceleration = force/mass of the vehicle * deltaTime

angularAcceleration = acceleration / wheelRadius;

The problem is that I am accelerating much too quickly (moving through the gears twice as fast as i should), and I think something big is missing. I decided that I wanted to try incorporating the moment of inertia for the wheels, but I'm not quite sure how to do this. I can calculate the moment of inertia just fine, but since I am converting everything to linear forces, I don't really know what to do with it.

Does this sound like the missing piece? The vehicle seems like its accelerating much too quickly in the low gears, but in the higher gears, it seems closer to what it should be. Any thoughts??