Creaking Praxis BB

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treetrees
Posts: 94
Joined: Fri Oct 04, 2013 7:34 pm

by treetrees

OliverRB yes your right about it being external but it protrudes into the bb to keep it there , you probably sliced off the end inside with out even knowing it . I had to release the shifter cables a bit then lift out the guide oval one of the holes in the praxis bb then fit it back , a bit of a pain in the rectal area .

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boysa
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Location: Too far from my bike.

by boysa

I sheared the tab off on mine during one of the many installations, and now have it attached with very strong double-sided tape.
"Deserve's got nothing to do with it." William Munny

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Trkorb
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Joined: Sat Jan 19, 2013 1:17 am

by Trkorb

Hmm interesting... Maybe I should be paying more attention! :lol:

rpenmanparker
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Joined: Wed Dec 29, 2010 1:47 pm

by rpenmanparker

When I installed a BB386 crank and BB on my BSA-equipped Merlin Works CR Ti frame, the aluminum seal sleeve was depressed by the small machine screw that holds the cable guide onto the bottom of the BB shell. That in turn fouled the oversize crank spindle and caused it to bind. I had to cut a couple of mm off the screw with my trusty Dremel cutting wheel so the screw would still engage the threads in the BB shell but not protrude into the inside of the shell and push on the sleeve.
Robert

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boysa
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Location: Too far from my bike.

by boysa

On my CAAD10, it actually stays in place fairly well without being attached, but moves enough to affect shifting during the course of a few rides. My first attempt to rectify the issue was to use a self-tapping screw, driven through the hole in the frame into the Praxis Sleeve. It worked just fine (I made sure it wasn't deep enough to make contact with the crank spindle) but when I switched from GXP to Shimano versions I went with the tape on the recommendation of a friend. So far, so good.

I think another option would be to remove the cable guide, install the bb with the holes in the sleeve aligned with the holes in the frame, then reinstall the cable guide.
"Deserve's got nothing to do with it." William Munny

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CBJ
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Location: Brooklyn

by CBJ

Mine has stopped making the ticking sound. Could it have settled in?

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boysa
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by boysa

Seems unlikely to me, as all of mine became worse over time. Has the weather changed? I believe this could be a factor, and I've certainly heard more/less creaking depending on temperature and humidity.

Of course, I'm keeping my fingers crossed for you!
"Deserve's got nothing to do with it." William Munny

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Calnago
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by Calnago

Well, anything is possible, so it could have "settled in" temporarily, and like Boysa said, the weather can certainly play a part. But most likely it will rear it's ugly head again at some point. Until then, enjoy the quietness. But when/if it does come up again, attack it with a vengeance and slay the creaky beast once and for all. Good luck.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

blue151
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Joined: Fri Jun 11, 2010 2:39 am

by blue151

Sorry to dig up an old thread - I had a shop reinstall my praxis bb as it was clicking. Asked them to use loctite (to which they proceeded to use 242) to interface between the bb sleeve and the alloy bb shell.

Am I likely to run into issues later when I have to remove it? or will it not bond properly and will my clicking likely resurface? (I am a little more worried about the former than the latter)

Cheers

fabriciom
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Joined: Mon Aug 31, 2015 8:42 pm
Location: Madrid, España

by fabriciom

I had a frame with praxis pf30 solution and it made a small noise depending on what cogs I had selected. I though it was the pedals, changed that and nothing. Tightened even more the bb and nothing. I just learned to live with it.

I recentlight changed frame and needed a bb386 bb. This time I went with bbinfinite. Getting the bb in the frame was quite hard to say the least. On top of that it's glued. That thing is not coming out ever. Any who I transferred all my components. Now I have 0 noise.

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Calnago
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by Calnago

blue151 wrote:Sorry to dig up an old thread - I had a shop reinstall my praxis bb as it was clicking. Asked them to use loctite (to which they proceeded to use 242) to interface between the bb sleeve and the alloy bb shell.

Am I likely to run into issues later when I have to remove it? or will it not bond properly and will my clicking likely resurface? (I am a little more worried about the former than the latter)

Cheers

Loctite 242 is a threadlocker, not a retaining compound. Loctite 609, with a primer is what should have been used. Also, with praxis you shouldn't really need a retaining compound (except in rare cases) since it works by expanding a collet against the adapter cups and the BB shell. If the shell is worn or out of spec that's a different matter. And if you do use a retaining compound be careful on the drive side to not get any on the threads of the cup as it could drop through the gaps in the collet. The threads of the expanding collet should have a copper based antiseize on them. The clicking "may" actually be coming from the bearing/cup interface within the praxis BB itself.
Your shop, by virtue of the fact they used Loctite 242, does not know what they are doing.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

blue151
Posts: 47
Joined: Fri Jun 11, 2010 2:39 am

by blue151

I agree that you shouldn't have to.. but as a lot of people on this thread have experienced, it isn't uncommon for the praxis bb to creak/click..

Hopefully the loctite (albeit the wrong type) holds it well enough in place to prevent any further noise

titaniumconfidential
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Joined: Tue Jun 28, 2016 10:05 pm

by titaniumconfidential

Had several praxis adapters and unfortunately based on my experience they work great for the initial 2-3 months and then start creaking like crazy. I had enough of praxis. The company is great, their customer service is second to none but the product is not there for me. I needed a pf30 adapter for my campy it and thank god I found Wishbone BH as an alternative. I rode 10,000 miles combined on my bikes and had zero creaks. No loctite. no expanding collet. Press one side , and then thread in the other and done. Maintenance is easy.
More on the topic here: viewtopic.php?f=3&t=140901

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Calnago
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by Calnago

I meant to make a post here over a year ago regarding a repair I did on what was basically a throwaway frame at the time by most people's standards. I took some pics and then just never got around to posting, but now that this thread has been resurrected I'll complete the circle...

The background... Cat 1 friend was racing Cross on his Specialized Crux. Specialized OSBB with the 61mm BB shell... why they went narrower is anyone's guess, just dumb. Anyway, it was a carbon shell with alloy cups pressed in. Well, true to this type of bottom bracket's reputation, the fit wasn't all that great and the cups began loosening in the shell, creaking like crazy... and eventually just began spinning inside the shell. Then, during a race, they really broke loose but the rider carried on anyway. A real mess by the end. But it shows why this type of BB can become a nightmare and destroy a frame... here's some pics of the fiasco...
For an overview reference...
Image


and a bit closer view of the carnage to the carbon shell...
Image

I took some calipers to see just how badly out of spec it was at this point and let's just say it was the worst I've ever seen. Anyway, taking pity on my poor racer buddy friend, young and broke, I decided to take it on as "let's see" kind of project.
Oh, before I get to the repair part, here's a pic of the alloy cups that were spinning and grinding away the shell...take a close look at the edges of the drive side cup and you can see how cone shaped it is and ground away itself, compared to the nds cup...
Image

I figured the only possible fix for this would be through the use of an expanding type of collet assembly like the Praxis solution, and even then I wasn't at all sure it would work. But that's the route I decided to go down. So, upon receiving the Praxis OSBB converter BB, which consisted of two delrin (or similar) cups each with a lip of 3.5mm, to bring the shell width to a standard 68mm versus the original 61mm, and the BB itself, I tried to dry fit it just to make sure that it expanded enough to take up the gaping space that was now the BB shell. Guess what... with the cups in (completely sloppy inserted by hand), and with the BB inserted and tightened up to the max (collet fully expanded), it was still so loose that you could easily spin the whole thing by hand.
So, now some drastic measures needed to be taken... enter special epoxy and other fun stuff...
Image

That 3M epoxy you will not find at any Home Depot store. They use it in the heads of golf clubs etc... it resists some type of cracking that can happen in high stress applications and they have a pretty cool video on it. Specialized recommends it for inserting a replacement alloy sleeve. It is a permanent fix, and not meant to be removed. It is expensive stuff as well, and then that damn Applicator Gun which costs close to a hundred bucks itself made the whole endeavor a labor of love and interest and experimentation to actually see if it even could be fixed.

Anyway, the whole process once I thought it through in my head went like this...
1. Build up the damaged carbon shell with the epoxy as much as possible, the stuff has a set time of 20 minutes so needed to do the whole thing fairly quickly. It also comes in 40 and 60 minute set time versions.
2. Before the epoxy in step 1 above sets, insert the delrin adaptor cups from Praxis, and press them in with a press, mostly just to make sure they're in all the way and evenly, since a press was certainly not needed at this point due to the loose nature of everything. I was hoping that the drying epoxy would bond both cups to the shell and sort of "fix" the damage to the shell all at the same time.
3. Prime the inside of the cups with Loctite 7649 and the outside of the Praxis BB in prep for Loctite 609, the retaining compound.
4. Apply the Loctite 609 to the inisdes of the cups and the outside of the praxis BB parts that would mate with the cups.
5. Press in the Praxis BB from the non drive side.
6. Quickly screw in the drive side piece of the Praxis BB and wrench it all the say to expand the collet fully. I had to hold the non drive side securely with a wrench since as I mentioned before the whole assembly was so loose (even with the collet fully expanded) that it would spin in the shell. Therefore I was really hoping that the combination of the expanding collet and the adhesion of the Loctite 609 retaining compound would hold it well enough. I had no doubt the epoxy was going to hold the adapter cups in place.
7. Once it was all done, then all I could do was sit back, let it all cure for a day, then assemble everything back up and hope my buddy could at least finish the cross season on this thing.

He wanted to try a SRAM single ring setup, so that's what we did...
Image

And guess what... to this day that set up is still going strong without nary a peep. And he's certainly put it through the paces in nasty nasty weather. Perfect.

Still... the whole fiasco really illustrates why pressfit bottom brackets can be such a pain in the ass and if not secured very well, can lead to frame damage to the point of rendering your frame a throwaway.

Ok... that's all folks.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

hornedfrog
Posts: 235
Joined: Tue Feb 28, 2012 9:13 pm

by hornedfrog

Great post. Thanks for the thorough breakdown.

Yea DP420 is some wicked good stuff. Crazy shear strength.


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by Weenie


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