Difficult to explain, hope you get the gist…. Changing the BB on my bike tonight, noticed that there are two types of bearing system on the stuff I have been using..
Hope BB, the metal bearing face actually contacts the crank spindle on a machined surface.
Shimano/Gub BB have a plastic insert that is both a bearing cover/shim. This plastic sits on the crank spindle where it passes through the bearing. Remove the plastic cover and shim insert and the bearing is obviously a rattling fit on the spindle.
The drive side of the bearing had play in it so I swapped it out. On checking it looks like the plastic spacer has worn or compressed, causing the play. The actual bearing looks ok. Its a shame to scrap the BB for the sake of the plastic part…
Any other peoples experiences? Can you find these plastic parts as new replacements anywhere?