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Discussion Starter · #1 ·
I'm starting to consider switching to a Trek Emonda. The main concern I still have is BB90 durability. Considering the bearings are pressed directly into the carbon frame without any sleeve or nylon cups, I'm under the impression that a few bearings changes could mess up the tolerance over time and ruin the frame. Is it a valid concern? Or could a seized bearing grind out the carbon cups?
 

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I'd be more concerned with the tolerances to begin with and the creaking.

BB90 isn't anything magical over BB30, they both suck really bad if you ask me. The problem with BB90 is there isn't much of a workaround for it, you're basically stuck with dealing it. So over time it will only get worse if anything.

It's why I don't anything from Trek. Really stupid move on their part, really stupid.
 

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I don't work for a Trek dealer, but I do work on a fair number of Treks. That said, it's actually one of the least problematic non-threaded BBs, at least the ones I work with have been problem free. They are up there with PF86 for reliability. The most problematic seem to be the narrow versions, i.e. true BB30 and PF30. Even in those cases when you do everything right problems are far less common than many people realize.
 

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Discussion Starter · #4 ·
I don't work for a Trek dealer, but I do work on a fair number of Treks. That said, it's actually one of the least problematic non-threaded BBs, at least the ones I work with have been problem free. They are up there with PF86 for reliability. The most problematic seem to be the narrow versions, i.e. true BB30 and PF30. Even in those cases when you do everything right problems are far less common than many people realize.
But aren't problems almost sure to happen down the road, as insertion and removal of bearings start to take a toll on the frame?
 

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In theory yes, and certainly if the owner doesn't keep the bearing preload adjusted properly. However, if it's properly maintained you will likley change bikes before that happens. The bearings are slip fit, not press fit. So the R&R process should not be destructive at all. Even if damage does occur, Trek sells a bearing set with an over-size OD. And if it goes past that, I've been told you can send the frame in for repair. If someone here works for a dealer, I'm sure they can expand on that.
 

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Unless you anticipate frequently removing and re-installing the bearings, I can't imagine this being a concern. Routine bearing replacement over the life of the bike should not be enough to cause problems, assuming it's done properly (using the proper tools)
 

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Just anecdotal, but every bike I've bought in the the last few years has had clicking, creaking bottom bracket problems EXCEPT my 2013 Trek Domane with BB90. I had the bearings replaced after 4000 miles because one was feeling rough when the crank was out. The new ones are are silent and smooth too. I am 6'3" and 200 lbs. and put a lot of force into the BB.
 

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Unless you are riding in the rain alot, or dirty environment you should be able to get plenty of miles between changes on those bearings. The ones in my Domane today have over 15,000 on them and are still smooth. If the frame get's to worn for a nice fit with the standard bearing, Trek has a bearing you can get that is a little oversized. Eventually it will wear out sure, but you'll probably swap frames before then unless you plan on keeping it for much over 50,000 miles of riding.
 

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BB90. Not. A. Problem.

That's after hundreds and hundreds over the last nearly 10 years. And being good friends w/ a fellow mechanic that works for a UCI Womens ProTour team on Trek. rcb78's comments are right on.
 
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