I had to fix the rear hub on Emma, the MTB. I’d previously taken it apart while replacing a spoke and didn’t put it back together properly, it would appear. Apparently you’re not supposed to tighten the ‘cones’ quite as much as I did. This explains why the hub didn’t have much free play after I put everything back together, and the wheel wouldn’t spin freely for more than about a second. It should have just spun for many seconds until friction gradually slowed it down. Too much friction == harder to ride. It’s been quite hard work for the past week or so.
After getting organised with the right tools, some grease, cone spanners and a HyperCracker for the cassette, I disassembled the thing once again. I was greeted by the sight of small pieces of metal inside the hub. Not good. I cleaned up the cone and saw that it was pitted on one side, so obviously that was where at least some of the metal fragments had come from. I pulled out all the bearings and cleaned them up, along with the inside of the bearing. Everything else looked ok, so it appears the metal of the bearings is harder than that of the cone, so doing it up too tight crushed some of the metal of the cone. Erk.
I’ve regreased everything and put it back together properly (not needing the cone spanners or HyperCracker after all). It’s spinning freely about as well as I can remember it ever working. With luck the damage isn’t too bad and I’ll get a fair bit of life out of the hub before I need to replace it.
It’s a lot of fun playing with bike bits, though. :)