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Tech Shimano PF BB 92 41 problems.

leicaman

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Hi all
I was wondering if anyone could shed some light on what is best to use when installing a shimano pressfit BB92-41. I've recently been having some problems with a creaky BB. Last week I took the crank out and regreased the contacts between the crank and the BB. I didn't realise it at the time, but when I pulled the crank out, the drive side BB shell came out with the crank. It's obviously not a tight fit at all which it probably why I'm having creaking issues.
After regreasing everything and putting the crank back in , it was silent for one ride. Halfway around my ride on Saturday it started making a noise again though . I once again pulled out the crank to regrease it (I used really crappy grease the first time round) and then realised that the drive side BB shell had come out too. I'm pretty sure the BB should DNA very tight fit in the frame so I was wondering what I should do , and should I use some kind of compound then installing the bb shell?
The shell is a plastic/ nylon affair and my frame is just carbon with no sleeves. I did read somewhere that loctite 609 or 641 can be used but a quick check on amazon came up with nothing for 609 and 2 hits for 641, one of which was 27,000 yen for a bottle. The other was almost 4000 yen.

What would you suggest I use when installing the BB? Should I get a new BB that will hopefully be a better fit?

Thanks in advance

Mark
 

GSAstuto

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mau

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Recently I've been to Viva Home in search for a cheaper tubular tire cement. Spending a hour into the glue/adhesive section i saw these different types, color, sizes and price of these "Loctite" products. Im just not sure about this "640 or 641" type but with all their line up, there might be one. Try and check if there is a home center near your place.
 

GSAstuto

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mau

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@Tim its just a curiosity that I'm looking for a cheaper glue. I saw one but didnt buy it. Actually that is the same brand i used for my tubular as well, taken from your post's regarding tubulars, cements etc..., And I myself is very satisfied with it. Its just when i used it recently, I've notice that there is nothing special with the soyo brand compare to the regular rubber glue as like that. The smell the texture the color the way it bonds, but I just dont know about the real formulation of it. But based on my judging its practically the same thing. That is how i came with the search. Well of course its the brand, the "for tubular" specification its brand reputation etc. (IMHO)
But i haven't proven it yet.
 

mau

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Why?- to get a cheap alternative in times of desperation and crisis.
-for some mental self satisfaction? I guess.

How?- by trying both substance in something and comparing the result and saying "i therefore conclude that the blah blah blah". (Its just like science lab in HS.) And eventually trying it on tubs.


Again "may NOT have" it means its not yet proven too, @Tim have you?

Well i am referring to a rubber cement that is really the same with that soyo brand not like a wood glue, pipe glue, leather glue or something that just bonds. Alternative to the "bike brand" specific. This thing that I'm referring is very common in my place because, and is also used back in the early days of my father in their tubs when i was just a little kid and when these brand specific thing were not yet commonly available.

Enough for this mental thing of mine. Im sorry @leicaman for hijacking your thread mate.

Cheers
 

GSAstuto

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Well, Leicaman rides tubs, too - and in any case you might move this over to the Wiki and start a section on Tubular Glues.

1) But for the BB's - Almost every mfg will have strict guidelines of the installation materials.
2) Locktite is almost always specified by 'brand' - the various numbers refer to viscosity, curing requirements, material compatibility, etc. Use what they say to use and your success rate will be high. They DO test this stuff, btw.
3) You can McGyver just about anything on a bike and substitute this for that without generally causing much mayhem...
4) ...Except for the stuff that keeps you generally upright and safe on the road... then don't mess around unless you are willing to accept the risks.

As for the SOYO glues - they worked out the formula which provides the best adhesion for the materials under wide range of conditions. Same with Miyata tape - it's co-developed with 3M to provide bonding for tubular tires to rims. (Not doorway jams, shoe soles, etc). That being said - you might be able to find suitable equivalents. FE has done a HUGE amount of testing - especially related to CX where you need to change tires alot - that get's expensive and troublesome at 1500yen/ Miyata Tape Roll. I'm not sure he'd share all his findings as they are somewhat 'trade secret'. But you might ask.

Anyway - another useful compound (and recommended by some mfg) for BB is to use CarboPrep. We use the spray stuff sold by Effetto. It sprays on wet, then dries to a semi-viscous adhesive. If you have parts you want to remove or change position, this works great. And it has a corresponding CarboPrep Cleaner Solvent to get the sticky stuff off the part, too.

As a very <hijacky> side note - I've used alot of stuff on the road to emergency stick a tire. Bubble gum, Post Office Glue, doubleback tape, duct tape, rubber cement, tar, tile cement and tree pitch. I generally carry a small tube of Panaracer glue in my kit. It covers almost any situation - including that for our clincher brethren of an excellent boot adhesive. It's not so great for PF BB cups, though. (I've tried it).
 

leicaman

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Thanks for the replies everyone.
@GSAstuto - which would you recommend on a carbon shell with shimano PF 92-41? Carboprep or loctite 640? I'm guessing loctite will probably form a stronger bond between the two but is it a real pain to get an old BB out if it has been installed with loctite 640? I realise that it will most likely be destroyed when removing it.
Cheers.
 
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GSAstuto

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@leicaman if you're going for the 'I might need to service this often' route - then I generally just clean very well and use carboprep. This is what I do on the Uni race bikes as they need to be serviced almost every week - typically full teardowns and often bearing replacements due to regular dunks in the rice paddies and constant riding in the rain. If you prefer to get it as quiet as possible and plan on mostly nice day riding, then use the Locktite. Nothing should be destroyed when / if you remove the cups - they'll just be tougher to press out. I've only occasionally seen where the adhesive causes any lifting of the CFRP. The main hassle of Locktiting something is just cleaning the residue afterwards. That usually requires some solvent and sanding or scraping. I'm surprised the cups are fitting that loose - typically they are quite snug. Have you contacted the frame mfg to inquire if this is normal? Or what they specifically recommend for installation?
 

AlanW

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Press fit BBs really are a bag o' shite. Cheaper for the frame manufacturers to make and a massive pain in the arse for owners.
As Tim says the cups should be a mild interference fit in the frame, not a clearance fit, so it sounds like something is out of tolerance.


Sent from my iPhone using Tapatalk
 

leicaman

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After removing the grease from the BB area, it seems to have quietened down again but for how long, no one knows. I was surprised to see some YouTube clips showing people installing the PF BBs with an installation tool (tl-bb12 or 13... Can't remember which one is the installer of the top of my head). The BBs seemed pretty damn tight. I can just slide mine right in with no effort.
I emailed canyon to ask about it (and a problem I'm having with my creaking DA cassette). They sent me a garbled email about the cassette to which one fellow rider commented "was that written by Nario Quintana's insane old aunt ?"
They failed to even mention my problem with the BB.
 

GSAstuto

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@leicaman. I just don't think that's right. Every PF BB I've installed is a slight interference fit. In fact the CAD drawings of our frames will concur. BB Shell ID is generally .04mm undersize. I just checked a bunch more drawings and the same ... Between .05 and .03 mm undersize. Alloy are about .5mm undersize, then finished to .05-.1mm undersize.
 

leicaman

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@GSAstuto which do you think is more likely to be the culprit, the bb shell or the PF BB? I guess I should really order another bb to check. The loctite 640 arrived today but I'm a little reluctant to use it on the current BB as I may need to switch it out.
 

leicaman

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Just reminded of this thread about DA-9000 cassettes.
Yeah, cheers mate. I've been reading through that thread (upto page five at the moment). Mine hasn't shattered but it is making creaking noises. It's definitely the cassette because the noise follows the cassette, no matter which of the three wheel sets I put on my bike. If I switch the cassette to another cassette, the noise stops, on all three wheel sets. Stupid dumb DA cassette. Canyon want me to take it to a local dealer and get them to check it out. Apparently they will pay upto 50euros to have this done. Not sure how on earth I'll claim the money back off them though. Their customer service seems pretty bad when I call them. The "English" technical support line has people answering the phones that clearly don't have the first clue about bikes, and cannot speak English very well. Their only response to my three phone calls is "I'll get a technician to email you the answer".
 

Sibreen

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which do you think is more likely to be the culprit, the bb shell or the PF BB?
Are you sure it is one or the other, and not the crank-crank connection?

Next time it creaks, take off the non-driveside crank and then put it on again and see if the noise stops. I had a similar problem and loosening the non-driveside crankarm then tightening it up again stopped the noise for a while (though not permanently).
 

leicaman

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Are you sure it is one or the other, and not the crank-crank connection?

Next time it creaks, take off the non-driveside crank and then put it on again and see if the noise stops. I had a similar problem and loosening the non-driveside crankarm then tightening it up again stopped the noise for a while (though not permanently).
The creak isn't there at the moment but I think the underlying problem is that either the BB is too small or the bb she'll is too big. The BB slides inside the BB shell by hand pretty easily. Once it is in, there is no play, but I don't think it should slide in so easily.
 
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