Geeetech

Okay, I fixed it. The sheet metal part of the carriage was out of angle by some degrees where the bottom wheel is screwed on.
I bend it back into position and the rest was done by the eccentric nut.

Thanks

Thanks so far, but this can't solve it. The bearings are tight but the distance of the bottom wheel is maybe 10-15mm to low to push against the aluminum profile. The eccentric nut can't push that far. How strong should the wheels have contact to the bar with a normal unit? It's there still some spac...

I have the same problem. Could you please upload a photo of this fix? Thank you