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I have a Canyon Ultimate CF SL which has the all to common press fit bottom bracket creak.

I use 24mm Shimano Chainset and have tried the official Shimano Ultegra BB86 and 92 Bottom Brackets, a Rotor bottom bracket and most recently a Wheels MFG Screw in BB.

I have tried installing dry, with grease and with Loctite Surface prep and Loctite fixing compound.

None of those solution have rectified the issue. Clearly the tolerances of the BB shell are not correct and it's not out of warranty.

Does anybody have any ideas of what I can do as a last ditch attempt to fix frame - please understand that the alternative is a new Frame altogether - so invasive options are fine.

I am currently thinking of removing the Wheels MFG bottom bracket that is currently installed - clean up the BB shell as good as possible and reinstall the BB bonding it to the frame with Epoxy resin.

The Wheels MFG has replaceable cartridge bearings - so in theory these could still be changed even if shell is bonded to the frame.

Are there any major flaws in this idea? The only one I can think of is that it'll stop be from ever using 30mm axel chainsets.

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    I would consider installing a shim, made from pop/beer can material. One advantage of the can is that you can pick the thickness based on how far down the side of the can you go. – Daniel R Hicks Jan 2 at 13:40
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    Have you put a set of vernier calipers into the BB shell of your frame? It should measure 41mm. If it doesn't, then you've found the source of your problem and we can make suggestions based on that. – Carbon side up Jan 2 at 13:53
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    @DanielRHicks I don't think the 'gap' is even big enough to shim. That said I can't really see it because all of the bottom brackets have an outboard 'lip' that obscures the view. – 111111 Jan 2 at 15:40
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    Can you speak to what you've done to ascertain it is the BB/frame interface? Has the noise changed but persisted with the different things you've tried? Was there ever a permutation where it went away completely? Notably, can you logically eliminate the noise being a hidden issue in the frame somewhere? – Nathan Knutson Jan 3 at 5:05
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    Does it install particularly tight or loose? If you measure the bores with a caliper in different spots, any clues of ovalisation? Lubricated every conceivable frame fitting, chainring bolts, and swapped pedals? Crank spindle and splines greased? – Nathan Knutson Jan 3 at 5:21
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Park Tool offers the RC-1 specific press fit BB retaining compound. As I understand it expands slightly when cured to take up space between bearings and slightly oversize frame cups.

  • Ok, I'll try that and then see if it improves anything. If that fails do you think the epoxy route is worth pursuing? I don't see how it could fail really. – 111111 Jan 2 at 15:42
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    Having looked at the page you have linked, and seeng that it needs a surface prep compound - I am almost certain it'll be the same as the Loctite 770 (primer) and 641 (Bearing fit) compound I've already used. It wouldn't surprise me if it's a rebadge of the same thing. – 111111 Jan 2 at 15:44
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    The Park retaining compound is similar to or possibly the same as 641. – Nathan Knutson Jan 3 at 4:59
  • @NathanKnutson - that's what I though - might skip this - seems like another money sink for something I've already tried. – 111111 Jan 4 at 14:07
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It's hard to give a complete answer without having some internal diameter (ID) measurements from the shell. You want to know whether you're dealing with ovalisation, too small of an ID, or what. If it is an ovalisation type problem ("ovalisation" may be somewhat of a misnomer because if so it was probably made that way as opposed to being an acquired problem) then you want to know whether you're dealing with some spots being too small while the rest is on spec, or some spots being gappy while the rest is on spec, or perhaps some of both.

If those measurements revealed some spots where the ID numbers were too low while the rest was good, then reaming and facing may solve it completely.

If the measurements showed the ID was too high in some spots, causing the press fit interface to not work as it should (i.e. the cup contacting the tight part of the oval and being loose or gappy in other parts), you might try an approach of building up the bore with bondo or epoxy and then reaming it down to perfection.

I suspect but don't know it's this second possibility you're running into. Loctite 641 has a gap fill spec of .1mm, and the interface wants an interference fit of another .1mm on top of that to work right and not creak. So in other words, you can approximately think of it like if there's any spot in the ID that's larger than the cup OD itself, the Loctite might not cut it.

There's debate whether using reamers on all-carbon frame parts is a good idea. The general concern, as I understand, is along the lines that the cutting operation may sever a carbon fabric layer, resulting in the frame being weakened. Some sources, Barnett's for example, say don't do it. I asked Park specifically before replying to this whether putting their #744 reamer through an all-carbon shell would be a good idea. Calvin Jones replied to me with the following:

The 744 can trim carbon fiber material without issue. Carbon fiber is not like a pair of blue jeans, where a thread is pulled and things come apart. Much like cutting a carbon fiber fork column, the resin holds things together.

I do think there's probably some kind of hypothetical risk of hurting the frame by reaming an all-carbon shell, but I think it's where I would tend to go in a case like this if the ID measurements indicated it might be helpful.

In BB30-land, special oversize-OD bearings are available that can solve press fit problems when nothing else does, in the case of bores that are larger than spec for example. I don't think anything like that exists for BB86/92.

I don't like that if the epoxy plan doesn't fix it, or only fixes it for a while, you've got a huge mess on your hands. But creaks indicate movement and epoxy is often pretty good at obliterating movement, so maybe it would work great. It's not what I would do first from what you describe.

  • Fantastic reply. I really appreciate you taking the time. I have ordered a set of Mitutoyo calipers (which i need anyway) so I'll measure the ID of the BB shell. What I would say is if it turns out that the frame needs reeming the cost of the tools required to do this would end up costing more than the value of the frame itself - like I said this is a last ditch attempt. As for your last paragraph - what I am doing is basically attempting to save a frame that'd over wise be chucked in the bin before it's time. I'll report back when I've measured the ID. Thanks again. – 111111 Jan 10 at 15:18
  • At this point there are shops around that have the reamer in question. Creak problems on press fit frames are common after all. I work at a large shop and we have the Park 744. – Nathan Knutson Jan 10 at 19:10

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