Creaking Praxis BB

[treetrees]

I went to asda yesterday and the cashier asked me if I wanted a bag for life , I said no I married one . Just thought Id cheers us all up . I know it's a rubbish joke

[Calnago]

Removal of these things when a strong retaining compound is used is always the "elephant in the room". @Highdraw, earlier in this thread I asked you how many of these types of Bottom Brackets, installed with retaining compounds such as 609 or stronger, or with even greater gap filling properties than 609, have you actual experience in removing from carbon frames. And how has that shell been after removal? I've discussed this with a very prominent carbon repair shop and they really have come to dislike some alloy cups which can compress the resins in the carbon shell making a not so great fit even worse. So, perhaps you missed that earlier post, but would still love to hear some anecdotes of your actual real world efforts in removal, especially on some of your more challenging situations. Thanks.

[highdraw]

Removal of these things when a strong retaining compound is used is always the "elephant in the room". @Highdraw, earlier in this thread I asked you how many of these types of Bottom Brackets, installed with retaining compounds such as 609 or stronger, or with even greater gap filling properties than 609, have you actual experience in removing from carbon frames. And how has that shell been after removal? I've discussed this with a very prominent carbon repair shop and they really have come to dislike some alloy cups which can compress the resins in the carbon shell making a not so great fit even worse. So, perhaps you missed that earlier post, but would still love to hear some anecdotes of your actual real world efforts in removal, especially on some of your more challenging situations. Thanks.

I resisted answering your question Calnago earlier because it is much too broad in context. There is a vast difference between BB30 and PF30...latter can use either alloy or plastic bushings/cups...or a sleeve.
Also Loctite 609 is NOT a strong retaining compound. This is deliberate. 609 offers very little resistance in shear..again by design. You see, things like Praxis or Wheel Mfg sleeves, alloy cups, bearings etc when it comes to bonding to BB30 and PF30 frames need very 'little' help to keep quiet.
In fact grease 'almost' works. It has competing properties as it turns out to keeping bearings quiet. Grease is incompressible...the problem is as many report...it can work for a weak and then hydraulic out like a mini pump out of the outboard crevice. This is promoted by its fluid state and lack of being captured...there is an outboard crevice escape route. Plus grease is lubrice aka slippery. I likes to squirt out if given the opportunity. Instead a fluid that solidifies aka cures and its sticky aka bonds to adjoining surfaces is preferred. This is fundamentally different than grease and why Loctite works better. Grease promotes movement and not encumbers it...the opposite property you want for keeping bearings quiet.

So, just a bit of retention goes a long way. That is why Loctite 609 is effective. Also, a fluid that solidifies dramatically stabilizes the contacting surfaces by increasing surface area. No different concept than carbon paste on a seat post or handlebar clamp that doesn't solidify but stays a liquid. Carbon paste fluid becomes captured in the cracks and dramatically increases contact. Fluid when compressed acts like a solid if it can't leak out. But grease can leak out between bores and bearings/sleeves/bushings...and by contrast Loctite which turns into a solid can't.
Plus, grease is slippery...the exact opposite quality desired to mitigate movement between pressed or close to slip fit surfaces.

I have worked with Loctite corporate in an engineering capacity to develop specific applications in the past.
As it turns out there sometimes is very little in common between different formulas other than the trade name Loctite. There is nothing in common between 242 for example compared to 609. Formulas are application specific and if you have a big enough contract, Loctite may even develop a more specific new formula.
Their products developed by their PhD chemical engineers work. Adhesives are replacing mechanical fasteners to reduce cost, weight and complexity in spite of many not liking this approach.

As to disparaging carbon...no. Loctite in fact...residual Loctite left by pushing out bearings/bushings/sleeves leaves a more perfect round hole in fact in the carbon. A mold is created by the pressed in part. So residual Loctite...a very fine coating actually protects the carbon shell and doesn't disparage it. Of course re-application of Loctite sticks effectively to residual Loctite. For BB30, bores can be readily cleaned up and a hundred repetitions of bearing replacements can be performed on a given frame.

As to how many different BB's I have worked on? Lost count. I have worked on hundreds of race bikes...mostly helping club riders resolve their issues that their local bike shops screw up. Devil is in the details.

[justaute]

FWIW...I've similar experience with my one-and-only Praxis PF30 BB. Decided to use a Kogel and it's working fine so far after ~1.5k miles.

[highdraw]

FWIW...I've similar experience with my one-and-only Praxis PF30 BB. Decided to use a Kogel and it's working fine so far after ~1.5k miles.

PF30 as opposed to BB30 with Praxis seems to be more sensitive to creaking for reasons discussed above.

[justaute]

FWIW...I've similar experience with my one-and-only Praxis PF30 BB. Decided to use a Kogel and it's working fine so far after ~1.5k miles.

PF30 as opposed to BB30 with Praxis seems to be more sensitive to creaking for reasons discussed above.

I see. I guess a sampling of one isn't quite sufficient. haha. Well, at least the Kogel unit is still quiet (fingers crossed).

[jwfinesse]

I wouldn't use loctite 609 and primer on nylon pressfit bb. When you try to hammer out the loctited nylon bottom bracket, bearings just fiy out, leaving you nothing to work with except an empty shell.


This is what happened to my previous Parlee Z5, and I had to dremel the crap out of it until I had something to grab onto with a plier, and yank it the hell out. Not something you want to experience on a $5k bike. Trust me.


However, I've done multiple installs with Chris King PF30 and Wheels MFG PF30 BBs, all of which are made with aluminum, on the same frame with loctite 609. No hassle installing and removing.

[goodboyr]

Yikes!

Interested to know which tool you used to try to bang out the cups. In my experience, the BBT30.3 does a better job than using the RT-1. But I've used both. And as you've experienced, I have sometimes knocked the bearings out of the cups using the 30.3. So, I then had to use the RT-1 carefully positioned to bang out the cups. Sometimes you need a heck of a lot of force to get them out (bigger hammer.......) but they've always come out for me.

[jwfinesse]

Yikes!

Interested to know which tool you used to try to bang out the cups. In my experience, the BBT30.3 does a better job than using the RT-1. But I've used both. And as you've experienced, I have sometimes knocked the bearings out of the cups using the 30.3. So, I then had to use the RT-1 carefully positioned to bang out the cups. Sometimes you need a heck of a lot of force to get them out (bigger hammer.......) but they've always come out for me.

BBT-30.3 for me I banged on that nylon shell for an hour, hoping to get it loose. I'm a big guy, and used iron hammers instead of a mallet, but it just wouldn't budge. Bearings flew out in the first blow, though. Regular nylon pf30 job (dry or with grease) starts to come out with one good whack.

[highdraw]

I wouldn't use loctite 609 and primer on nylon pressfit bb. When you try to hammer out the loctited nylon bottom bracket, bearings just fiy out, leaving you nothing to work with except an empty shell.


This is what happened to my previous Parlee Z5, and I had to dremel the crap out of it until I had something to grab onto with a plier, and yank it the hell out. Not something you want to experience on a $5k bike. Trust me.


However, I've done multiple installs with Chris King PF30 and Wheels MFG PF30 BBs, all of which are made with aluminum, on the same frame with loctite 609. No hassle installing and removing.

If you look at Specialized installation procedures for both PF30...their narrow version called carbon OSBB and for their industry std. BB30, they spec them each very differently. They don't spec Loctite for their plastic bushings. This is because they found that epoxy is better than Loctite as an adhesive to bond the plastic bushing to a virgin carbon shell. This is probably for many than one reason.

To me what killed PF30 for Specialized is they never went to a plug an play integrated bearing with alloy cup solution that you did jw. Plastic bushings with press in steel BB30 cartridge bearings plain suck and offer very little bearing retention and tend to creak. What has saved the day for PF30 are solutions like you have chosen.

As goodboyr wrote...with the right tools, you should have been able to knock out those bushings without having to section them with a dremmel and yank the pieces out. Those bushings come out much easier as one piece...again if you have an expansion type punch to located on enough of the back edge of the bushing to apply more even extraction force.

Best tool for the job:
http://www.amazon.com/Park-Tool-Removal ... B00426BAGQ

[Calnago]

Good info @jwfinesse, especially about the Chris King PF30 cups which I specifically wanted to know about. I've done multiple installs as well with 100% success rate but always wondered what it's going to be like getting it out in the event of a repaint (which one guy wants to do on his Evo that I fixed up last year). So thanks for sharing, the pic is very useful as well. I'm thinking of getting one of those Air Hammers like the guys at BB Infinite use for removal of their BB's.

[goodboyr]

Just as a warning, you need to be super careful positioning the RT-1 expansion tool against the back side of the cup. If you slip or misposition that tool, the sharp edges can gouge or chip the carbon fiber bb shell, in particular at the outer edges as it passes by.

[highdraw]

^^^ Very true.
And back to jw's post...its just another problem with separate BB30 bearings pressed into thin plastic cups as shown.
For removal since the bearing will pop right out, removing the cups becomes quite tricky. Yes, with grease or installed dry, the bushing can be removed with little effort. But many creak if installed dry. And if you use Loctite with this application to adhere the bushing to the carbon shell, removal can become more difficult.

For above reasons, the variety of different integrated alloy bearing and cup designs out there like Chris King, Wheel Mfg's solution and many others excluding Praxis' expanding collet...this is the way to go.
Separate plastic bushings and bearings are no good. Simple fact is, not only are integrated bearing and cup solutions much quieter if you Loctite them...but they are much easier to remove because you can punch them out by punching on the bearings and not the cup edges. The bearings are typically Loctited in from the factory or have a high enough interference level that they won't creak or come out.

So this stuff is nuanced you guys and within a family of BB30 and much more so with PF30, it depends on what choices are made for your BB...integrated bearing and alloy cup solutions are the most reliable.

[jwfinesse]

Rear view of my used Chris King PF30, which I still have on my desk as an eye-candy:) The banged-up lip behind the bearing is where the crucial difference lies when removing alloy cups vs nylon cups. Alloy lips are significantly more impact resistant than plastic/nylon/etc. When those lips give in, bye bye bearings.

I've had 3 bikes with creaking BB30, PF30, and all of which were successfully remedied with loctite 641 or 609. Loctite works so well (too well in my other pic) it is like green magic potion to me now.


edited to resize the pic.

[treetrees]

Ok peeps I have just loctited my wheels mfg bb in , so will give an update when I can sneak a cheeky little ride in .