alexcoupson

Hi, so currently i own a trek madone 5.5 that has a bb90 bottom bracket. What ended it happening is, since the bearings on this bike press strait into the frame and have no protection whatsoever against the bearing the carbon ended up wearing down to where the bearings fit loosely into the frame over time. Bike shop wants me to pay 250 to surface them again. Instead i went and bought a better (used) frame that uses bb86 bottom bracket style with a cup/sleeve that goes on the bearing then pressed in. i know that these tend to make creaking noises some time but i dont mind. The question is, has anybody ever experienced a bb86 bottom bracket wearing down a frame to where its useless. Or does it just wear down the sleeve? i dont mind replacing bottom brackets rather then throwing a frame away. On the trek i cant even ride it in the rain or else the none drive side bearing seizes and wears down frame.
The new frame is a 2009 giant tcr advanced sl team. for the price of 500
-much happier getting an entire frame for just a little more then what is costs to get the dumb trek fixed. Knowing its going to break again soon

WizardOfBoz

There's another solution for the BB90. You can buy bearings that are slightly oversize. Trek had them made. They are like 37.1mm OD rather than 37. I can't imagine that they cost 250.

Of course, every time you install new bearings in a CF frame you should use TFE paste grease. Properly installed and maintained BB90s should not have worn your frame.

alexcoupson

trek did offer me the larger bearings but they also had issues. My trek dealer told me i had a bike year (2008) that was known for having the problems and it will keep happening. The newer years with bb90 started making stronger bb shells so that it doesn't wear down

smarkinson

In a bb86 the frame shell is aluminium while the bottom bracket that contacts it is plastic (at least on my shimano bb they are) so you really shouldn't have any problem.

John_V 

My long time riding buddy had the exact same problem as the OP on his 2012 Madone 5.2. They replaced the BB that was under warranty and told him that if that one goes they would have to resize the opening and go with a different size BB. So far, the BB is still nice and tight but it sure does make noise when under a load.

TimothyH

There are replacements bottom brackets which do away with pressfit altogether.

Praxis and Enduro Torqtite both make replacements that screw together and require no pressing.

exmechanic89

Stories like this really show how bad press-fit BBs are, imo. It's a true bummer to pay that much money for a high-end bike and then have this issue. In your friend's case I would be wondering what the situation would be in 10 years if I chose to keep the bike that long. Couldnt be good. And jeeze, I'd expect a nice quiet, smooth BB for that money, not something that makes a racket under a heavy load. I really hope manufacturers go back to threaded BBs on the next generation of bikes.

gyshfor

Maybe try getting angular contact bearings while you're at it? I'm currently debating myself if I should get a Wheels Mfg threaded BB86 or not, some reviews on amazon don't seem that convincing but then again it is quite possible that some people don't know that you should put more preload on angular contact bearings as opposed to regular ones.

FrozenK

So a problem specific to some Trek model is enough to cast all press fit away?

I have a Kona with a BB30 press fit bb that has been OK for four years now, including four seasons of cross racing. And thousands of miles on road and gravel, riding in rain, etc... My Yeti also carbon and press fit BB -although running a Praxis BB- but going on third year without issues. Before the Yeti I had another Kona with a PF92 BB, also zero issues despite thousands of miles on singletrack -a lot of them on some ****ty, wet weather.

Press fit BB aren't perfect and yes, they demand a well made frame. But Jesus on a pogo stick, according to the interweb's they are the worse thing since cholera.

As for the OP, doesn't Trek offer a lifetime warranty on those frames? Because that's a warranty issue if I ever saw one.

exmechanic89

Well I'm glad you love press fits so much, but I didnt base comment on just this one situation. For me, no thanks on press-fits.

TimothyH

@alexcoupson

Enduro makes a replacement for BB86 which does not press in but screws in.
https://www.endurobearingsonline.com...s/torqtite-bbs

The same goes for Praxis.
https://www.praxiscycles.com/conversion-bb/

Neither of these are adapters but full, replacement bottom brackets which do away with pressed in bearings or pressed in cups altogether. There may be other brands.

I have the PF30 version of the Enduro Torqtite on my Niner RLT 9 RDO. Installation was stupidly easy.

-Tim-

hueyhoolihan

sounds like it should work as long as the BB has some sort of metal insert. otherwise, i would think the cups threading together in the middle could crush a fully carbon BB.

Canker

I just installed one of the Wheels Mfg threaded bb86 deals on my carbon cross bike about a month ago. So far no complaints and it is nice and quiet. Just follow the instructions and it is pretty simple. I did build my own bearing press out of threaded rod rather than spending the money on another never used again tool.