3 years ago my race bike, while new to me, was very very worn out. In a matter of about 2 months I ended up replacing most of the moving parts, and since I was tearing it all apart I decided to replace the cheap-o BB adapter with a nice ceramic conversion job. I spent money on it, and I've never regretted that choice.
But after about a year, water intrusion became an issue and it started sounding like a cheap Walmart bike. I tore the whole bike down to a pile of nothing and used some exotic automotive racing grease to repack the bearings, and it spun better than when they were new. It was so good, in fact, that I got into a 6-month routine of tearing down and repacking the bearings with Redline CV-2. That stuff is amazing, but it doesn't last forever, and I put a LOT of miles on that bike.
A couple weeks ago I started feeling a little notchiness in the drivetrain. I'd been cautioned that ceramic bearings do have a lifespan, so I was hopeful it was just time for another repack, but concerned that they might be at the end of their life. I tore down, cleaned, and repacked the drive-side bearing and it rolled smooth as butter. But the non-drive-side bearing, well, I didn't make it very far into the tear-down before things went sideways.
If you're not familiar with bearing construction, or you've never torn one down, a ceramic 2437 angular contact bearing is built thus:
Deconstruction usually begins with removing the seals, which is tricky because they're very thin and fragile, and basically will be damaged by the process. NBD if you keep them dry for the rest of forever.
Disassembly then moves to removing the retainer, which is wedged in place by the ceramic balls. It's not a load-bearing part: its whole job is to keep the balls evenly spaced. In mine, the gaps between the balls have little castellated crowns that hold and distribute additional grease. It's the center object in this pic:
These castellated crowns make a great engagement point for pushing the retainer out the back side (black seal) of the bearing. And that's where things went bad. These bearings had just about 11,000 miles on them, and even with grease they go through a lot of heat cycles. The tool pushed out the first one without incident, but the 2nd retainer snapped. Uh oh.
What broke off resembled the circled part below: enough retainer to carry one bearing, with backing over 2 others. The rest came out intact.
But the way it broke, I took a chance that my non-load-bearing component could be salvaged! Also I had no other real options available, and ordering new bearings--even non-ceramic options--was going to take a couple of weeks.
My thought was that, since the broken piece could firmly hold one ball and extend "wings" to cover two adjacent balls, it would not twist inside the bearing and destroy the whole thing. The larger intact portion would simply butt up against those two outer balls and its overall structure would prevent it doing damage.
So I cleaned everything up as best I could, put it all back together very carefully, and took the bike inside.
There's still a touch of notchiness that you can feel under load on the trainer, but it's undetectable on the road.
I've put about 250 miles on the bike since doing this bodge repair, but so far the whole thing seems pretty solid. There's no question the bearing has no future. It's ruined. But for now, and maybe for a couple of cold trainer months, it seems my "fix" will hold. Or at least I hope so. Fingers crossed!
