Hello fellow GameDevs, I'm developing a simcady-style vehicle physics model. Till now I've developed the Engine and  the Clutch Model (Thanks to Clutch Modelling topic from here). Till now I had been using Unity WheelColliders, but now I'l have to use a custom wheel collider to better simulate the forces. The Unity WC doesn't allow to change the RPM of the wheel, which seems really unrealistic. 

Firstly, I went to Unity's Alternate Vehicle Physics Model, didn't like it much. Edy's explanation of his Vehicle Physics Pro model on his website https://vehiclephysics.com/ pushed me into developing my own Tire Model. As said in his articles, he uses Slip Velocity instead of Slip Ratio and Slip Angle and as to why it isn't realistic in this.

But now I'm stuck. I calculate friction coeff from an animation curve, put on the slip velocity to evaluate and multiply it by the load on the tire to get the Tire Force.

But, since forward slip requires angular velocity, and angular velocity depends on tire force, it oscillates between positive and negative. Even the Longitudinal Force oscillates between positive and negative.

Can any of you please help me??

Thank You.