suspension set up?

Could be ABS kicking in and jostling your suspension a ton? Might simply come down to execution when driving. I'll make my own version of this car and report back with any findings.

Update: Made a balls to the wall version and tested. I think it's a combination of how open wheel designs behave in BeamNG and ABS at this moment. Further testing is required in order to fix the issue. Might need to lower tire width and/or rim offset to begin with.

thank you i will try it out and post what i find

I've done some testing in BeamNG, and it seems that having ABS on causes the wheels to shudder and shake a lot more than without it. Don't use ABS+TC, ABS, ESC, ESC+TC in Automation and it'll transfer over to BeamNG.
Regardless, there is a little shaking from the wheels when braking, but that seems to be identical across a couple other Automation and BeamNG cars. It might have to do with the physics engine of BeamNG, not the exporter.

Many high-end track car setups tend to behave weirdly in BeamNG.

only use rear break make front brak as small as posible and rear as you want it

Car is very light. I'm trying to find a workaround but basically i have a 500kg car and set the brake to 160mm only ! Little to no shaking with ABS but i experience brake fade.
Also, as this is a small car : go to 15" wheels.