[Physics] How to combine multiple PhysicConstraints? (for creating wheels with spring)

I started to wireup a wheel and noticed(in the BP-Editor), that setting a ConstraintName as ComponentName is not valid. so how do i combine multiple constraints.

Okay i got everything working so far. My vehicle moves quite nice(tuning required but off to a very good start). I face one small issue though:
After accelerating to a given speed, it is like driving over small bumps sometimes. Like there was a little stone or something(but the whole surface is a single plain mesh). I already checked my constraints to be aligned properly. The wheels are centered properly. Yet i can’t find the cause for it :frowning: