Wheeled Vehicle Physics Problem

Hi, I´m trying to get a Wheeled Vehicle Pawn to work, but it just won´t drive properly.
When ever the wheels have ground contact, the vehicle starts to jitter around and when moving forward, the wheels randomly jump up in the air, throwing around the entier vehicle. It is like the vehicle desperatly wants to roll on it´s roof and tries to glitch through the ground.

The problem goes away if I remove the box around the main part of the vehicle in the phat editor, but then it won´t drop to the gound anymore, which likely is why the problem disappears.

I followed the documentation exactly, my models pivot is at 0,0,0, the root bone is at 0,0,0, in phat, the wheels spheres are set to kinematic and the box that covers the cars body is set to default. No part of the model is below 0 on the z-axis, I used reset X-form before skinning, othing intersects something else and the wheels move as intended.

Here are some screenshots of my BPs. I also added the project as a .rar, maybe someone could take a look at it and see if he can find the source of the physics glitch.

The model (.max and .fbx) and the ue4 project: Dropbox - File Deleted

Did you set all 4 wheels in vehicle movement?

Dont use “Kinematic”, try setting “Simple” Physics type (because Kinematic does not work and it even fails at Phys Asset Editor’s simulating test, unlike “Simple” type, which works).

Also dont forget to change all of your joints to “Simple” (not just Root, wheels need to be manually changed as well)