So a month ago I gave my bike to my LBS to do some stuff on it, among these things, they regreased the rear triangle bearings. 2 hours ago, I noticed a carbon crack in the rear triangle. When I press on it some of the bearing grease behind comes out. And if you squint, you can see the round bearing pressing against the carbon. The carbon crack is lateral, and I don't see how riding the bike normally would ever cause this
by Wrong_Barracuda_860
7 Comments
And I don’t know exactly when this crack happened
Looks like they used a compression style bearing press on a hollow portion of the carbon arm maybe? The bearing press mark is very clear, I would talk to them
Did they remove the bearings themselves or just the bearing seals?
That crack didn’t happen at the shop
What’s the year/brand/model of bike? I don’t see how the bearings could be installed into the seatstay (?) shown here. Based on what I think I see on the far side, it looks like the seatstay end is double-shear and the bolt is installed from the inside. That’d ordinarily mean the bearing is in the rocker (if that’s what the blue part is) and there’s an insert nut in the outer part of the seatstay. Suspension design has been the wild wild West, though, so would need specific bike info to be more sure.
If that’s the design here, it _may_ have happened at the LBS but Idk if I’d say it’s their fault. If there’s a bonded nut insert and the bolt is super tight from Loctite or corrosion, loosening the bolt has the potential to drag the nut with it and radially stress the carbon composite due to anti-rotation features built into the outside of some nut inserts. If that cracks the carbon, is that the LBS’s fault? Or, is it the fault of the bike designer who could’ve used a different joint design utilizing an exposed nut that can be held by a wrench?
No idea what I’m lookin at here
If it is their fault. Good luck fighting them. There’s a small chance they will be cool. But more than likely say “we didn’t do that” and that’s all there is to it.
I’ve been in this situation twice. Once my bike got damaged at the shop. And the owner accused me of lying and trying to scam him, the other a worker at a shop stole parts off my bike and the owner denied it, and ended up filing a police report before they ended up taking any action to make it right. ( And that’s only because it was cheaper for them to replace my parts themselves rather than go through their insurance)