Error in roll angle?

Hi,

I did a very basic simulating, in that I constantly accelerate and turn left. This leads to a spiral trajectory in (x,y).

After a while the vehicle becomes unstable. Upon investigating the reason, I discovered that the vertical tire forces on the right (F_z_RF, F_z_RR) decrease and eventually become zero. This is where the car becomes unstable. At the same time the vertical tire forces on the left (F_z_LF, F_z_LR) increase. See the following plot

From basic principals I would expect exactly the opposite during a left turn due to rolling to the right, i.e. an increase on the right and a decrease on the left. As well the suspension movement (z_SLF,…) is decreasing on the right and increasing on the left.

Can you explain this behaviour?
Also is a negative roll angle left or right w.r.t. the driving direction?

Thanks and best regards,
Timo