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Which Shimano BB pressfit you like the most (pest or cholera)

by Woody the mamil
Thu, Nov 02, 2017 14:24
13

Hello chaps and ladies:)

I have to buy a new roadbike (crashed in the Hamburg Velo) and the eternal question is which BB pressfit is the least problematic (yes they are all crappy I know) My new bike will have Shimano Dura Ace Di2 which limits me to Shimano pressfits. £20 piece of plastic stuck in the high end bikes... the mind boggles!

Whats your thoughts BB92 or BB86, personally if I can get a bike with BB 90 that would be my choice. I had the Trek series with a BB90 and never any issues (except they wear pretty fast) I know its individual and that all frames are different and if there is a microscpic difference in tolerances this causes the bike to sound like its got gravel in the BB frame. I just think with all complaints running on all bike manufactuers (that ive read over the years) why cant Shimano design something that is more robust. Unfortunatley my budget stopped me buying a new Trek Emonda and I really like the look of the Canyon Endurance SLX 9.0 the only downside is it has the dreaded BB86!!! 

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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13 comments

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Woody the mamil | 7 years ago
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Hi again T.V. Thanks for your long winded answerkiss It sounds to me like well worth giving it a go.  I guess I am more worried about the crappy plastic cup and tiny screw to adjust the headset on the Canyon cockpit. Thanks anyway, I might just end up getting a Trek SLR with BB90, problem solved

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Woody the mamil | 7 years ago
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Thanks I will check it out!

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Woody the mamil | 7 years ago
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Hello TypeVertigo, Sounds really interesting with BBinfinite and Hambini.  Is it possible to assemble the two piece praxis into a Canyon Endurance SLX frame? The standard setup is the SM-BB92, I thought you could not use anything else than a plastic pressfit in the frame.

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CXR94Di2 replied to Woody the mamil | 7 years ago
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Woody the mamil wrote:

Hello TypeVertigo, Sounds really interesting with BBinfinite and Hambini.  Is it possible to assemble the two piece praxis into a Canyon Endurance SLX frame? The standard setup is the SM-BB92, I thought you could not use anything else than a plastic pressfit in the frame.

Hope and wheels manufacturing list BB 92 conversion Bottom bracket

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TypeVertigo replied to Woody the mamil | 7 years ago
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Woody the mamil wrote:

Hello TypeVertigo, Sounds really interesting with BBinfinite and Hambini.  Is it possible to assemble the two piece praxis into a Canyon Endurance SLX frame? The standard setup is the SM-BB92, I thought you could not use anything else than a plastic pressfit in the frame.

Sort of a long-winded answer incoming...

If you were to buy a crank from Praxis, say their Alba or Zayante cranks, they're now sold in the M30 format. Basically this is Praxis' own take on the 30 mm crank spindle, but they borrow a trick from SRAM's GXP cranks - the spindle steps down at the non-drive side; in this case, to 28 mm.

I was pretty convinced such cranks wouldn't work on a BB86 frame, because not enough space would be left over for BB bearings that are any good. Apparently Praxis made it work. They sell M30 bottom brackets for BB86 frames. Unlike most BB86 bottom brackets, though, they have no cups. They're basically bare cartridge bearings that you press into the shell.

So, long story short: yes, you can press metal into a BB86 frame. It's a similar deal with BBinfinite and Hambini, where their modules are all metal, but will press into the shell just fine from the non-drive side. I suspect they've all got the machining just right for the mild interference fit necessary to press them into the frame.

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ChrisB200SX | 7 years ago
1 like

I had my BB86 replace with new 105/Ultegra (5800/6800) end of June, was lovely for a few weeks, until I really put some power down up a hill, creaks even worse than before now, but only over a certain amount of force, basically cranking up hills or really pushing the power on.

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FatAndFurious | 7 years ago
2 likes

I had a problem with the DA press-fits - basically, the bearing slid out with the crank spindle when I was doing a little maintenance on a really hot day.

I'm guessing the alloy frame expanded just that little bit more than the plastic container/race/outer edge (whatever it's called) to reduce the compression just enough.

I was able to push it back in by hand, and it's worked fine since. No creaks or wobbles, but it was a surprise to see it come free.

PS I have a CeramicSpeed BB86 for sale, red, unused, shiny......

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Jimthebikeguy.com | 7 years ago
1 like

Whatever it is, just put money aside to replace it with a better threadfit type (praxis or wheels mfg) when it fails. Bb30 seems to be the most common culprit.

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TypeVertigo replied to Jimthebikeguy.com | 7 years ago
1 like

jterrier wrote:

Whatever it is, just put money aside to replace it with a better threadfit type (praxis or wheels mfg) when it fails. Bb30 seems to be the most common culprit.

Actually I'd suggest a one-piece bottom bracket module instead if you really want to eliminate all creaking. Everything else, including Praxis, is made of two pieces that either fit together or screw into each other.

For one-piece options, you have BBinfinite and Hambini. Hambini in particular has a YouTube channel with really good analysis of press-fit bottom bracket standards and why they have their problems.

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Woody the mamil | 7 years ago
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I guess it sounds to me like there is no singling out a specific bad pressfit. I guess you hit the nail on the head stating manufacturers producing frame and BB to exact specs. This I am afraid is the problem. I was in Gran Canaria with a mate who had a high spec Focus (1 week old) It sounded terrible. We took it to a Bike shop and they were able to remove the press fit both sides with their fingers! I wish they could produce pressfits with small mm tolerances + 0.5mm at a time. This would help I think with small tolerances on the BB carbon frames. 

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Woldsman | 7 years ago
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My Giant-equipped carbon bike came with a BB86 - that was five and a half years ago.  I've had no creaks (touches wood) apart from those that come from my elderly knees.  Oh, but then I don't get out much...

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700c replied to Woldsman | 7 years ago
1 like

Woldsman wrote:

My Giant-equipped carbon bike came with a BB86 - that was five and a half years ago.  I've had no creaks (touches wood) apart from those that come from my elderly knees.  Oh, but then I don't get out much...

 

Ditto - my Giant BB86 has been fautless since I got it, though that is using campag with their own metal cups in the frame. No additional adapters or whatnot.

I guess any system relies on both manufacturers producing frame & the BB to exact specs as pressfit systems have very low tolerances.

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TypeVertigo | 7 years ago
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I don't know about you, but BB30 and its ilk has much more trouble than BB86/92 does. Asking a 30 mm aluminum spindle to hold up structurally while it spins inside hardened steel bearing inner races is a creaky disaster waiting to happen. 

Personal experience on my BB86 bike reveals a largely creak-free life. When it does click, I find that it's usually addressed by cleaning the old grease off my Shimano 105 FC-5750 crank, regreasing, and reinstalling. There is a reason why Shimano sticks to a 24 mm steel spindle - it just works.

I'm 7100 km into my current SM-BB91-41B Dura-Ace-level bottom bracket. It's still spinning smoothly. Prior to this, I had an FSA Omega 46/36T crank that spun on its own bottom bracket bearings because it had a 19 mm steel crank spindle. As fashionable as it is to crap all over FSA, I never had problems with that crank or its BB either.

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