Review on Igus RJ4JP 01 08 Printer Bearing Replacement by Jonathan Fernandez

Do not use for Prusa heatbed. After installing them I thought they were perfect because the bed rocked back and forth easily and quietly. Surprisingly, it only worked well for 4 hours, then one or more of those plastic bearings started to stick, resulting in a printer error with "error detection", which happens in Prusa when stepper motors offer too much resistance to the movement. I loosened each u-bolt holding each bearing with literally a slight twist of the ubolt nut on each, but then during a new push it loosened so that the push looked rough, too much play in the bearings. This does not apply to steel nuts, which are less likely to deform when clamped with U-bolts.