Wheel position on the ground

Hi, once again I need the forum help to solve a problem. I got a simple vehicle setup (no suspension) that I working on and I am currently having an issue between the wheel and the ground. the wheel tends to enter the ground and gets pushed back everytime causing instability. The wheels collision are not handled by physic boxes, they are handled by two separate vehiclewheel blueprints. So I manualy configured the radius of my wheels.
This is what it looks like before it hits the ground, notice the black collision boxes on each wheel:

and this is when it comes in contact with the ground:

this lag makes it impossible to control the vehicle normaly. you can still accelerate (at some point) and steer (it tends to deviate)
I would like to know how to fix this issue

thanks in advance