So my 3D printer uses two 10mm rods for the X axis with LM10UU bearings inside the toolhead carriage.

The regular metal bearings are quite noisy and have nasty resonance effects at 40mm/s speeds. They also have a lot of wiggle room.

In an attempt to solve this I bought the plastic variant which has no moving parts and just slides over the rod. They are too tight however and my printer struggles with moving in the X direction.

Does anyone have experience with these? I assume the plastic ones wear out over time so the friction should go down.