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Nick Payne
Joined: 10 Jan 2004
Posts: 2626
Location: Canberra, Australia8/21/15 1:09 AM |
Press fit BB creaking
The BH bike I recently put together for my wife is the only bike in our garage with a press fit BB, and it creaks at the BB when she stands out of the pedals. I googled "press fit BB creaking" and it seems that the only thing standard about press fit BBs is that they creak...some of the messages I came across indicate that people are servicing their press fit BBs on almost a monthly basis to keep the volume of the creaking down:-( Give me a threaded BB shell and square taper BB any day - they're pretty much fit and forget for years at a time.
Anyway, this frame has a BB386 press fit bottom bracket, with the plastic housing of the FSA BB fitting directly into the carbon fibre shell of the frame, and as the cranks I used have a 24mm axle, there is an additional plastic adapter for the 24mm axle to fit the 30mm i.d. of the bearings - ie there's several interfaces where the creaking could be happening. I greased everything when assembling it initally, but while investigating the creaking I noticed there was some slight play observable when grabbing the end of the crank arms and moving them relative to the frame.
I pulled the cranks and without them in place couldn't detect any play between the BB shell and BB, nor in the bearings themselves, nor between the 24-30mm adapters and the bearings, whereas the crank axle is a slightly loose slip fit through the adapters. As the easiest course of action I degreased the axle and internal surface of the adapters and reinserted the axle with some Loctite 609 between the axle and adapters. Tomorrow's ride will tell if it's a fix or not, and the next couple of weeks whether the fix will last. If not, I guess I'll be knocking the whole BB out and fitting a replacement with Loctite between all interfaces, which is actually the recommendation on the Park Tool web site for press fit BBs:
http://www.parktool.com/blog/repair-help/bottom-bracket-standards-1
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walter
Joined: 11 Jan 2004
Posts: 4391
Location: metro-motown-area8/21/15 8:35 AM |
this is comical
remove BB threading from the frame and re-introduce threading to the press-fit BB. i guess it achieves the OEM goal: removing production costs from the frame, shifting that burden to the owner. at least the enduro gizmo looks well made.
LONG LIVE BSC/ITA BBs...FTW!!!
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Sparky
Joined: 08 Dec 2003
Posts: 19083
Location: PDX8/21/15 11:19 AM |
I refused to throw money at the BB30 noise on the brand new BB30 Roubaix last year.
Praxis etc, my ASS! ;)
Engineer the fucking thing right in the first place before you toss shit out to the consumer!! That and poorly implemented internal cable routing, not to mention an overly stiff build [as to have less warranty payouts VS ride comfort?], are all the reasons I have the Green Machine now, and am Roubaixless...
I went to the auto parts store and got two 20mm thin red high temp o-rings and used as compression spacers, one on each side, noises gone. I first used the butyl rubber bands that came on the tubes I buy for a test run, and it worked. So I went seeking the O-ring for a more permanent solution.
Worst part was I could not get Specialized to say the Praxis BB would not void the frame warranty. Nothing I have to worry about anymore...
If you creak is the BB in the shell, I don't think the compression spacers will do it. You'd have to put so much load on it it make not sense for that approach. My noises were crank slap upon sudden efforts of watts, such as I put out these days...
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Brian Nystrom
Joined: 26 Jan 2004
Posts: 5101
Location: Nashua, NH8/22/15 6:02 AM |
While the BBs are known for creaking...
...it's quite possible that the end play is the issue. I ran into that with a Super Record crank. The single wave washer allowed the crank to shift laterally, which allowed the bearings to shift and creak in their cups (Campy is unique in that the bearings are attached to the crank, not pressed into the cups). A combination of a second wave washer and Loctite 641 between the bearings and cups remedied the issue.
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walter
Joined: 11 Jan 2004
Posts: 4391
Location: metro-motown-area8/22/15 6:37 AM |
I always run
...2 wave washers as my default. Stack of spares in the parts-bin.
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