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Old 05-04-06, 12:41 PM   #1
DocRay
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Yet another creaking crank thread...

I need ideas.

I had trouble with creaking end of last season, and I thought it was my rear wheel hub.
This season, I started out with new wheelsb and a new crank- perfect silence until tuesday.
Wednesday, the creaking is back. It may be the BB. all other bolts are tightened to spec.
The difference between tuesday and wednesday is 15C vs. 26C air temperature, and from what I remembered last season, creaking was worse at higher temps.

The BB is an FSA ISIS. Time for a new one? (~3000km on it).
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Old 05-04-06, 01:00 PM   #2
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I always suspect BB + lack of frame prep in these cases. I'm assuming you've ruled out anything pedal or saddle related?
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Old 05-04-06, 01:24 PM   #3
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I have a brand new ISIS BB and it's creaking like crazy. I cleaned the threads and reinstalled it three times and still no luck. Worst of all, it is quiet after I reinstall it then starts up again 5 miles from home. Took it to LBS to let the mechanic have a look, and he couldn't get it to creak. I wonder if this is an ISIS problem, or you and I are just having bad luck. 3000km shouldn't need a new BB, that's like 2 month's riding for most racers.
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Old 05-04-06, 03:46 PM   #4
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Does it still creak when you come off the saddle and pedal?
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Old 05-04-06, 04:17 PM   #5
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urbanknight, did you face the shell when you prepped the threads?
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Old 05-04-06, 06:07 PM   #6
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Quote:
Originally Posted by Al1943
Does it still creak when you come off the saddle and pedal?
Yes. I'm thinking that I need to re-torque the BB. It's not a pedal issue, it's not the seat.
FSA bbs are somewhat iffy from what I've read. I'm reading good things about token ISIS BBs.

Any ideas why temp makes a difference?
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Old 05-04-06, 09:29 PM   #7
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Quote:
Originally Posted by Landgolier
urbanknight, did you face the shell when you prepped the threads?
I'm not familiar with the term. What exactly does that mean? But unless it means clean the threads and blow any debris out, then no I didn't. As to the above comment, I don't notice it creaking when I come out of the saddle. I am gathering that should indicate the creak is not in the BB?
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Old 05-05-06, 01:37 AM   #8
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Facing means using a facing tool to cut the face of the bottom bracket shell so it's flat and perpendicular. Otherwise crookedness and what I call "jingus torque" (seating against the high point, not good even seating all the way around) result when you crank the BB torque up to spec. If you don't do this, you usually start to get a creak in 1k-2k miles.
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Old 05-05-06, 04:11 AM   #9
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I have a Token BB now, with a titanium spindle and actual carbon fiber on the shell. Kind of waste as it saves a whopping 10g if that and never gets seen. But This has lasted be two winters, a good amount of commuting, and plenty of MTB miles. 65 bucks brand new on Ebay.
When this one craps out, I will be making my own BB. As for the OP, try running through the installation process again. Also, make sure that the torque to the crankarms is sufficient. I like to use a torque wrench for crankarm installation
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Old 05-05-06, 11:01 AM   #10
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Thanks for the advice, all bolts are torqued to specs except the BB.
I need to order some tools to deal with this.
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Old 05-05-06, 11:09 AM   #11
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Quote:
Originally Posted by Landgolier
Facing means using a facing tool to cut the face of the bottom bracket shell so it's flat and perpendicular. Otherwise crookedness and what I call "jingus torque" (seating against the high point, not good even seating all the way around) result when you crank the BB torque up to spec. If you don't do this, you usually start to get a creak in 1k-2k miles.
Would this be necessary on a new frame? I've only heard this done with Mega Exo BBs, and only when the BB shell was not aluminum.
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Old 05-05-06, 11:35 AM   #12
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This should be done on all new frames, but shops can't afford to put the labor into it. Take it to a shop, the tools are expensive.

I've faced BB shells new and old, Al and steel, and I've never seen one that came from the factory straight. Take a look at yours with the BB off and you will probably see that the paint is a little more worn at one point, that's the high point.
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Old 05-05-06, 12:10 PM   #13
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Creaking

If the creaking goes away when you are off the saddle, it usually means that the source of the creak is either the seatpost, saddle rails or the saddle itself. Those are all pretty easy to take apart & clean, try a different saddle, etc. (trial & error) to pinpoint the problem. Good luck!!!
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Old 05-06-06, 12:49 AM   #14
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If the BB hasn't been faced when initially installed, then that could be a problem too. Just the paint on the surface can have varying thickness which then causes the cups to be deformed when tightened down.

Could also be loose threads, which is my guess. Aluminium expands at a faster rate than steel. So at higher temperatures, the gap in the threads between the aluminium BB-shell and the BB-cups would be greater, leading to more creaing. Fill this gap with teflon tape when installing. I use about 2-wraps of teflon tape on the BB cups typically. I usually start by wrapping too much and it binds a couple threads in. Then I back off, remove all the teflon and re-wrap with one less layer, repeat, remove if necessary, until I find just the right number of layers to completely fill the gap in the threads. Typically requires 1-4 layers of teflon tape.
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Old 05-07-06, 11:44 AM   #15
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thanks Danno, I was going to ask about teflon tape. The bracket was faced from the factory (Cervelo). But, the BB will be the last part I haven't rebuilt or adjusted on the bike.
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Old 05-07-06, 06:12 PM   #16
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I had a BB that creaked so loud I felt embarrased about it. It turned out to be the left cartidge bearing was not a tight fit on the spindle; the movement of the iner race against the spindle shoulder caused the noise. Uber strength Loctite did not fix it permanently either it would only last a few months. I threw it out in the end.
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Old 05-07-06, 10:08 PM   #17
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You could also try taking out your setapost, greasing it putting it back in along with your seat rails.
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Old 05-07-06, 10:39 PM   #18
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I recommend two things:

1. Use teflon tape on the BB threads. It can't hurt anything and eliminates a lot of these types of creaks.

2. This one is not so easy, but well worth the effort. Take your crankset apart - completely. Now reassemble, but grease every single mating surface. The screws and holding nuts, any places that two different parts touch each other gets greased. Any two "dry" pieces of metal rubbing against each other can cause a creak. Grease them all. A triple will take the better part of an hour to disassemble, grease everything, and reassemble. I hate doing this, but I do it on every crankset I install on my own bikes. And, I have fixed many creaks this way.

If you still have creaks, change your pedals and shoes to a different set to make sure it's not them. Lots of "BB creaks" turn out to be "pedal/cleat/shoe" creaks. In the shop, the first thing we do is install cheap platform pedals and try to reproduce the problem.
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Old 05-07-06, 10:46 PM   #19
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Quote:
Originally Posted by DannoXYZ
I use about 2-wraps of teflon tape on the BB cups typically. I usually start by wrapping too much and it binds a couple threads in. Then I back off, remove all the teflon and re-wrap with one less layer, repeat, remove if necessary, until I find just the right number of layers to completely fill the gap in the threads. Typically requires 1-4 layers of teflon tape.
Yes, this is an excellent strategy for teflon tape. I like enough tape so that you can screw in the BB by hand, but it should be smooth and still offer resistance all the way in. When you get enough tape on it just feels right.
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