Oversize bearings in out of spec Trek Carbon Shell BB

Discuss light weight issues concerning road bikes & parts.
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cyclespeed
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by cyclespeed

bikemaniack wrote:I see no sense to installinb BB bearings on Loctite. ust a little bit of grease and thats all. Why??...Did any bike company doing this? Did you ever seen BB mounted on Loctite in stock bike? Simple


I think you mis-understand. This is not a new bike, but a used one that has suffered wear / movement / warping of the BB shell. So the bearings are now loose.
Solution is either oversized bearings or some kind of retaining compound.

by Weenie


darnellrm
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Location: NC, USA

by darnellrm

bikemaniack wrote:I see no sense to installinb BB bearings on Loctite. ust a little bit of grease and thats all. Why??...Did any bike company doing this? Did you ever seen BB mounted on Loctite in stock bike? Simple


Yes, it is very simple. If you want an interface to move freely, use grease. If you want to inhibit movement, use a retaining compound.

TheKaiser
Posts: 511
Joined: Thu Sep 05, 2013 3:29 pm

by TheKaiser

darnellrm wrote:Yes, it is very simple. If you want an interface to move freely, use grease. If you want to inhibit movement, use a retaining compound.


Big points for brevity!

bikemaniack
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by bikemaniack

Sorry guys,thats true,I missed the point.

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kermit
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Location: Belgium

by kermit

androidavies wrote:As I remember, the Trek supplied oversize bearings were 0.1mm larger outer diameter. They have deleted them in the UK, I tried to obtain them to try and solve a similar problem.
Trek warranty dept. offered to try and "build up" the bearing seats again, I sent the frame to them but they decided it was too far gone for them to attempt. Fair enough…
I solved the problem by getting a friendly local machinist to make up a "top hat" cup/shim. I put the bearing into the top hat, then pressed the unit into the oversize BB seat. It's held for the last 14 months.
The times I've come across this have been when the original bearing has seized or disintegrated, and the owner has carried on riding the bike for quite some time….

Please don't think I'm making an accusation!



I am sorry to dig this thread up.

My trek '08 madone had the same issue. It was repaired by Trek - they have built up the bearings seat. All right you might think, but after 8000km the bearings where worn; Isn't this a bit early? The mechanic told me it is common to replace the bearings yearly... Can't believe this as they cost a lot more then standard bb30 bearings or so. He also told me this wouldn't last for ever...??

Mr.Gib
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by Mr.Gib

@ Kermit -don't apologize. This thread should be brought up regularly.

It is a disgrace that a company like Trek is selling what is essentially a disposable product. A carbon shell with slip fit bearings that are spec'd to be installed with grease means that it will wear out. And lets be fair to Trek, they are not the only company with this type of BB.

So you had Trek rebuild you bottom bracket. How much did they charge? I was told that if the bike is out of warranty that the rebuild is "not cost effective". That's why I will opt for the oversize bearing option.

As for your bearings only lasting 8000 km, what probably happens is some grit gets around the edges of the dust seals of the bearing and makes them noisy and gritty feeling when in fact the bearings themselves are perfectly fine. I don't know if those bearing have a weather seal behind the dust seal, but in either case there is a technique to remove the seals and clean things up. However $50 to $100 per year on bearings while not great, is a survivable cost if you don't want to mess with servicing bearings.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

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kermit
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by kermit

@Mr.Gib

It's supposed to be a lifetime warranty on the frame. So they didn't charge for the rebuild of the bracket seat. The shop where I originally bought the bike refused to help me. They stated it was my own fault. I just had to come earlier to service the bracket... So I shopped around and found another shop where the owner, after begging him, took care of the warranty claim. He promised I would get a new frame, so we agreed if this was the case he could build it up with a new ultegra. This deal persuaded him. No luck for him, because Trek only repaired... Anyway, I still think it's a bad construction of the frame. Apparently it's a known issue.

Servicing bearings? Every 3 months opening the lot and greasing? Where is the time that a bracket was something that just worked for ages. I have a old GT Avalanche MTB, 18 years old, with the same bracket... never serviced.

There was play on the bracket, not due to grid. It's just not sealed properly. Only thing is a rubber against the bearings . There is no plastic around! Washing or riding in the rain is almost enough to get water inside.

I wonder if the new Trek bikes have the same issue. Emonda, MAdone etc. I can't imagine their cyclocross bikes have this problem... In Belgium cyclocross is rain, mud etc...

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nickf
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by nickf

Don't see this issue on frames from the last couple years. Early bb90 frames, forget about it. Older frames do come in still with issues. I push here in Florida those hawk full stainless bearings, they really do last much longer then the cheap enduro ones.

Mr.Gib
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by Mr.Gib

I ended up going for the oversize bearings with the green seals that are mentioned in this thread. They appeared to fit snug, no play in the crank. Unfortunately, as one might expect, pressing a round bearing in an oval hole resulted in only about 2000 km of riding before the bearing started to complain.

Where to go from here? I was thinking of measuring the shell and trying to make it more round using a piece of steerer tube wrapped with emery cloth a'la Calnago on his Koppenberg, and then having another go with the oversize bearing.

Other options? Apparently it is not economically worthwhile to send the frame to Trek for a rebuild. Perhaps if I was closer to Wisconsin.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

Nefarious86
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by Nefarious86

Rather weak that their lifetime frame waranty doest cover defects..

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Mr.Gib
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by Mr.Gib

In a way the problem is covered by warranty. But instead of replacement Trek will supply oversize bearings or rebuild the BB to spec. The frame is second hand to me so I assume no warranty.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

spud
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by spud

goodboyr wrote:
Thu Feb 23, 2017 4:19 pm
I think trek changed specs and manufacturing practices several years ago when this came up. But this still comes up for other reasons. If the preload is set wrong on the crank, the slight movement over time will cause this to happen as well. So in summary, originally due to poor mfg tolerances but now mostly seen due to user error in preloading. I don't work at a trek shop, but I've seen my share of these. As an aside, I've always found that the NDS bearings on bb90 frames goes first. DS bearing usually is ok. Perhaps due to more protection from dirt and water.

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I've heard the same thing re NDS bearing, along with the theory that all liquids/crap on the NDS side of the downtube/Seat tube gets funneled directly to the bearing, whereas the DS has a flange around the bearing to redirect stuff. It's for this reason that I built up my Madone with Campy cranks, which require the use of a bonded in aluminum ring in both cups. Serves to change the ID/inset distance, while also providing a sharp ring to divert contaminants. Has worked so far, though I don't ride this bike in the rain much.

mattr
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by mattr

Mr.Gib wrote:
Sat Jan 20, 2018 2:44 am
Other options? Apparently it is not economically worthwhile to send the frame to Trek for a rebuild. Perhaps if I was closer to Wisconsin.
Machine shop take it out to 38/39 (depending how much material is there), epoxy a metal ring in there with a 37mm ID.
Needs someone who knows what the score is though. Need to get it very concentric......

Could make the bore deeper and add a stepped insert to locate the bearing.

mattr
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by mattr

Or you could see if one of those thread fit bottom brackets will fit. Might need to do some modifications to the frame or change crank.

ymisyd
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Joined: Mon Nov 20, 2017 12:16 am

by ymisyd

I had an old second-hand Madone where the frame had worn so badly the bearings actually fell out when I removed the cranks. I bought the oversize bearings and they still wiggled about. I actually cut some strips of an aluminium drink can, wrapped them around the bearings, and pressed them in with a smearing of carbon assembly paste. I know it's unorthodox but I had nothing to lose and it did the trick for me.

by Weenie


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