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  1. #1
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    bottom bracket problem

    I'll try to keep this short.

    A few months ago I had to have my bb replaced at the LBS. ( I didn't have the tools, then, DUMB). Actually, had to take it right back since the put the wrong bb on as the large chainring would rub the chainstay So, they put the "right" one on and everything's good, shifts fine, great, I'm off.

    I begin to notice after a couple of weeks the thing is really starting to creak (I've eliminated everthing else). So, not wanting to haul it back to the shop, I get the right tools and pull the bb, make note of the size, wrap it with plumber's tape and coat it with anti-seize, install, everything's good. Another week, it's creaking AGAIN. Repeat the process, everything's good.

    Now it started creaking again. For grins, I email the manufacturer what spec bb is supposed to come with the bike. They email back 73X121. Here's the deal. What I have in there is a 68X118. I measure the bb shell: sure enough, 73. I measure the clearance of each crank arm to the chainstay, about 5mm more on the drive side. Again, everything shifts fine, no interferance, but give me a sanity check on this: Is the reason I can't get the thing to stay quiet is because the non-drive side cup is not making adequate contact with the main body and after a few rides it begins to creak?

    Thoughts? (I'd prefer not to take it to the shop as they'll have it for a week, and I think I learned my lesson anyway)
    I'm looking forward to regretting this.......

  2. #2
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    Quote Originally Posted by johnnyspoke
    Now it started creaking again. For grins, I email the manufacturer what spec bb is supposed to come with the bike. They email back 73X121. Here's the deal. What I have in there is a 68X118. I measure the bb shell: sure enough, 73. I measure the clearance of each crank arm to the chainstay, about 5mm more on the drive side. Again, everything shifts fine, no interferance, but give me a sanity check on this: Is the reason I can't get the thing to stay quiet is because the non-drive side cup is not making adequate contact with the main body and after a few rides it begins to creak?
    Sounds like the right explanation to me. 3mm isn't much, but as you've found out, it's just enough for it to mostly work, but creak a lot.

    I think the bike shop owes you a correctly sized BB. Convincing them that they made a mistake on the sizing might be hard though. It's probably worth it to make the effort anyway. Bring in whatever correspondence you have from the bike manufacturer regarding the correct BB size along with the BB from the bike and see if they'll swap you a correctly sized BB. Bring in the receipt or work order from the previous work they'd done on the bike. (I've found that the more papers you have, the better chance you have of getting things to work out.) Don't bring the bike in. You sound like you know what you're doing, and, with your experiences thus far, I wouldn't trust them to get it right.

    If you don't get satisfaction, purchase a BB elsewhere and tell everyone you ride with about your experiences with that shop.

  3. #3
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    Yeah, I can't find the paperwork now. I guess I'll chalk it up to experience, and just do everything on my bike now (bb tools were about the only thing I didn't have at the time)

    Thanks for the help.
    I'm looking forward to regretting this.......

  4. #4
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    You shouldn't need paperwork or bike specs to verify if they installed the correct BB. A simple meadurement of the width of the BB shell should do.

    A 73x000 BB is for a shell measuring 73mm wide, while a 68x000 BB is for a 68mm shell.
    Measure your BB shell yourself and you'll know for sure.

    The spindle length determines how far out the cranks sit, and affects chain line. Too short and they hit the chainstay, too long and you'll have problem keeping the chain on in the low (inboard) gears.

    I suspect that part of your creaking problem is that the BB is too short to fully tighten on your wide BB shell. See if you can convince the LBS of their error (be nice here, a bit of tact will do you much more than a highly negative attitude) and have them install a correct BB. It should be at no charge since they provided both the wrong material and the labor.

    If the shop won't absorb the cost of their error, buy the correct BB and install it yourself.
    fb
    www.chain-L.com

    The key to solving any problem is to understand and address the underlying cause.

  5. #5
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    I ended up buying the proper bb today. This is a shimano ES51 hollowtech. Interestingly, as I took the old bb out and compared them, the bodies are the EXACT same size. The difference is in the plastic "adapter" that threads in the non-drive side. So I went ahead and installed the correct bb but down the road when it wears out, I guess I can use the "wrong" bb with the plastic adapter from this one.

    Thanks again for the help.
    I'm looking forward to regretting this.......

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