OKAY. I discovered things while trying to get the ATT into the game. All active Lightwave modders should listen up (especially you Extreme) because this is important. Here are my findings and a picture of my frustration:
WHEELS ARE NEEDED TO DETERMINE THE POSITION OF THE VEHICLE IN THE GAME. WHY?!?
Have two: vehicle spins about the axis with the missing dimension
Have three: game doesn't know where the vehicle is, so it appears invisible and the game lags a lot
Have four, five, or six: vehicle is fine
EXCEPTIONS: wheels cannot lay on top of each other because they are used to triangulate the known position of the vehicle. Hence Frozen Wheel Frenzy caused the Skid Steer to spaz out because the game didn't know where the wheels were for a moment.
[10:08:11 PM] jamesster: ... why would they do that
So what DDI decided to do was determine the position and rotation (pitch and roll in this case) of the vehicle not by comparing the angle of the parent null to the angles of nearby ground polygons and using averaging to figure out what the rotation of the vehicle should be, not by using the four corners of a box that would fit around the entire model to determine how high each corner should be, but by using wheels to stop the vehicle from rotating past the ground. Why else would vehicles constantly "fall" into the ground when their wheels are messed up? This had to be intentional. I think that vehicles are the only thing that use the ground to determine rotation, as raiders definitely don't. Monsters might but I don't remember. Just look at this crap. You can see that there are no wheels on the front, but I put them in the animation and in top view you can see them flying around.
I seriously can't believe DDI would do this because it's so buggy unless things are just right. But this does explain why vehicles like the Hover Scout have invisible wheels: all vehicles need at least four wheels, no exceptions.