Bottom Bracket

Discussion in 'Cycling Equipment' started by thekgb, May 14, 2008.

  1. thekgb

    thekgb New Member

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    hi there,

    i've read some of the archives about BB creak, and done some troubleshooting, but here is my problem. My BB/crankset only creaks when the RPMs are low. IOW, mainly when i'm grinding up a hill, or going from a stop to a start. Once i'm up and running it's fine. Sprinted with it yesterday: no noise. Did hard group ride: no noise. But starting after a stop sign, there it was.

    I just put the crankset/BB together a few weeks ago, and i knew the BB was slightly used (say 1000miles). I didn't have a torque wrench but i tightened it enough so that there was no wobble/play (still isn't any play) and it rode fine. It was fine until my race last weekend, and now it's makes this creak/grinding noise. I would describe it as a click with a slight grinding sound which happens in rhythm with my downstroke on the non-drive side.

    I thorougly applied grease to both cups and all areas of the BB/crankset. I altered my limit screws on the front derauilleur thinking maybe that when i'm in low rpm im usually struggling up a hill in my lowest gear and maybe the chain was rubbing. that didn't help.

    Is the BB failing? is it typical to only hear the creak in low rpm circumstances? can it possibly be over-tight?

    any help appreciated.

    Mike
     
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  2. kdelong

    kdelong Well-Known Member

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    I'm not sure that I want to talk to you as I might end up in Lubyanka Prison:D, but anyway, are you using a cup and cone BB or a cartridge BB? You mentioned that you applied grease to both cups.

    From your description it appears that you don't hear the sound when you are spinning put you do when you are pumping. It may be a pedal problem so you might want to try a different set of pedals and see if it goes away. It may be a crack in the frame so you will definitely want to get it fixed and not just ignore it. I doubt that the BB is failing. 1K miles is not a lot for a BB. It is possible that you do have it overtight and that the only reason that you hear it at low RPMs is because it is masked at higher RPMs.
     
  3. oldbobcat

    oldbobcat Well-Known Member

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    When you're grinding you exert more stress on the bearings. If this is a traditional internal bearing, have your BB shell faced. Torquing down the right-hand cup and the left-hand lock ring on a BB shell whose end surfaces are not square can actually distort the shell, preventing the balls from rolling true in their races.

    Facing squares the BB shell ends and is not as critical for external bearings.
     
  4. Albert 50

    Albert 50 New Member

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    Tighten the bejeezus out of it again. Then tighten it some more.
     
  5. Solanog

    Solanog New Member

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    I would check the pedals, I'm getting something similar in my MB and I think it comes from the pedal, the left one. I've had no time to check it but I will at least put some grease on them.
     
  6. kdelong

    kdelong Well-Known Member

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    Just checked my torque wrench. Couldn't find the "Bejeezus" setting anywhere:D! Exactly how may foot pounds is that, or would it be measured in mile tons?
     
  7. Lama

    Lama New Member

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    I was waiting for someone to pick up on that bit of Aussie talk

    FWIW - you dont need a talk wrench when going to the 'bejeezus' setting - just a really really long spanner - and stand on it
     
  8. oldbobcat

    oldbobcat Well-Known Member

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    Never tightened the bejeezus out of my bottom bracket cups. Once or twice accidentally overtightened a little and the crank wouldn't turn as freely.

    Tighten to the point where it doesn't wobble or clunk, then overtighten a smidgen before torquing down on the lockring. The lockring will pull the left cup out slightly.
     
  9. artemidorus

    artemidorus New Member

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    He's probably not using a traditional BB.
     
  10. Albert 50

    Albert 50 New Member

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    It appears to me that the outboard type cups are notorious for crick, cricken. Listening to even a slight constant every crank rotation crick is so annoying even when it is on a bike riding near you.
    The handle that comes on the BB tool [that I have] is short. You should be able to get it tight enough by hand but you may need a glove. The obvious answer is a torque wrench:) I wouldn't recommend using any sort of leverage device like a piece of water pipe to tighten any BB. Using pipe to loosen a stubborn one should be fine.
    Disclaimer:- Should you decide to listen or take notice of anything I say here or anywhere else for that mater do so at your own peril :eek:
     
  11. thekgb

    thekgb New Member

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    No i don't think i am using a traditional one, however my experience with them is limited. This one is for a SRAM force and is the type where the bearing are on the outer portion and they can be pulled off a center plastic piece (which the crank arm slides though to the other side).

    Just to update you: I took the BB out on Saturday. I noticed when i took it out that the cup things that went into the frame (which holds the bearing and the plastic thing) were a bit un-tight (not loose). I brought it to the LBS where after having 2 or 3 guys handle it, look at it, rotate the bearing parts...they all came to the conclusion that there was no clear signs that it needed to be replaced. they covered it with teflon tape and i re-installed it with lots of bejeezus style torque. the guy at the LBS said if you didn't make a funny face it's not tight enough. then I HEAVILY greased all parts. I took it out for a short ride up a steep hill and in the end it still creaked!?

    However, i did notice that 2 of the chain ring bolts were loose so i tightened them. I haven't had a chance to ride it since, but i'm commuting home on it tonight with a 45 min FTP interval, so that should give me an answer.

    -Mike


     
  12. Solanog

    Solanog New Member

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    I checked and lubed the pedals, I can't believe I really notice the difference, they felt really smooth and no squeaks.
     
  13. Yojimbo_

    Yojimbo_ Well-Known Member

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    Check the pedals again, as I bet this is where your problem is.

    I had a similar problem last year - brand new bike with a creak that appeared to be coming from the bottom bracket. The creak correlated with my pedals being in a certain position, and if I unloaded one pedal while turning the creak went away.

    Luckily I had just bought a set of identical used pedals for my other bike, so I was able to replace the pedal I suspected with a different one. And the creak went away.

    Good luck to you.
     
  14. artemidorus

    artemidorus New Member

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    Most of my clicks in phase with the cranks turning have come from the pedals or cleats.
     
  15. thekgb

    thekgb New Member

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    Well...it's still there, and so far we've reinstalled the BB, tightened the bolts on the chainrings, readjusted the derailleur. the pedals are up next. I'll reinstall them over the weekend. Would you all also recommend the "plumbers tape" around the threads for this too? could this be a crack in the frame that i'm not seeing?

    -Mike
     
  16. Solanog

    Solanog New Member

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    Besides the pedals I had a noise and it was coming from the seat. So everything must be checked.
    How new or old are your pedals?
     
  17. artemidorus

    artemidorus New Member

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    I have never needed plumbers' tape to fix any creak, ever, but I have no doubt that it works. Some grease, or, ideally, anti-seize compound, and adequate (but not too much) torque, are what I use. I have never had a creak coming from a pedal thread, except for one time with a second-hand bike where the thread was already fatally damaged.
    Unfixable clicks from worn pedal bearings are common, in my experience. Regrease, increase preload, decrease preload, change the ball bearings, they don't go away. What I do is to put another pedal on, confirm that the creak goes away, and then put the original pedal back on and ride it until I can't bear the click any longer. I won't throw away a pedal just for a click, not until it develops unfixable play in the bearing.
     
  18. scirocco

    scirocco New Member

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    Creaks can be really deceptive. They can sound like they are coming from the pedals but really coming from different areas. I've had creaks that were in sync with the crank rotations and one turned out to be from the saddle rails (like solanog suggested) and the other one was the carbon stem spacers were dry and creaking where they touched each other. Both of them you would have sworn blind were from the bottom bracket area. Tighten and lube everything, not just in the pedal/crank area.
     
  19. geoinmillbrook

    geoinmillbrook New Member

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    +1 . I was ready to tear my bike apart when I realized I had a shoelace tapping the downtube on each stroke once. Also had a loose spoke that sounded like a BB creak. As well as a squeeky pedal. I have found that using a torque wrench on the outboard BB bearings and tightening only to that which is specified by the manf'r really helped me with Truvativ/gigaxpipe BB's. Too tight was not good. As OP found chainring bolts creak too and I've locktighted all mine. Also torqued the crankset main bolt to that which is specified. A seat rail does the same thing as someone else mentioned. Most metal to metal noise seems to get picked up by the hollow frame tubes and resonates, hence the mystery of some of them. picking up on the cadence of the creak and what parts are moving at the same rate is where I usually figure mine out. Hopefully a crack in the BB shell is not the issue. That would suck.

    BTW I noticed all the shimano bb and crankset equiped bikes we have seem to be quieter than the SRAM/Truvativ ones. Have no campy stuff. Geo
     
  20. thekgb

    thekgb New Member

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    It was a loose chain-ring bolt. i finally got around to tightening them (correctly...i did it wrong the first time) and it's back to sweet silence. except for my huffing and puffing of course.

    thanks alot for the advice.

    -Mike



     
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