The word Chaos was specifically chosen.
They knew what the chamge would do to the engine well ahead of time.
In physX, the wheel have a RADIUS. Not a DIAMETER (or viceversa?).
Somehow, some way, 50% of the time I have seen your problem, the wheel definitions were set to use a measure that did not allow them to reach the floor.
In PhysX there is a specific collision command to visualize wheels and other bodies.
~ pxvis collision
Not sure if chaos being so badly made has anything remotely similar that would avoid you having to poke around.
If you can. Ditch 5. Go back to 4.27. Or build 5 without chaos while you still can (its already hard af).