Robert Kuki

Since the slipping seems to be mechanical, I’d try to isolate exactly where motion stops being transferred before replacing anything. Marking the shaft and the mating part can sometimes make it much easier to see whether the spline, plastic hub, belt or another connection is slipping under load.

I maintain a troubleshooting site for exercise bikes and other home fitness equipment here:
https://www.fitnessmachinehelp.com/

Full disclosure: Fitness Machine Help is my own website.

Nice repair. The fact that redistributing the clothes sometimes helped but the error kept returning is a useful distinction. On Samsung washers, Ur/Ub/UE are part of the unbalanced-load error family, but persistent banging with normal loads can also point to the washer's suspension or stability rather than simply how the clothes were loaded.

Your suspension-rod repair is a good example of why a recurring balance code shouldn't automatically be dismissed as user loading.

I summarized the Samsung Ub/Ur troubleshooting path here:
https://www.errasift.com/samsung-washing-machine-ub-error/

Disclosure: Errasift is my own website.

Before drilling or gluing anything, I would put a paint-marker witness line across the metal shaft and the plastic fan hub. Pedal the bike under load and then check which side of the line has moved. That will confirm whether the hub is actually slipping on the splines.

If it is the plastic hub, solvent or brake cleaner could make the plastic brittle, so I would only use a plastic-safe cleaner after testing it on a hidden area. Glue is unlikely to be a permanent repair if the female splines are worn. A replacement fan/hub or a properly fitted mechanical collar would be safer. A through-pin may work, but it can crack the plastic and needs to be drilled squarely.

This guide is mainly about belt-driven bikes, but the load-versus-no-load isolation steps are also useful for locating drive slippage:
https://www.fitnessmachinehelp.com/exercise-bike-belt-slipping/

Transparency: Fitness Machine Help is my own website.