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Old 10-21-11, 08:37 AM   #1
Telly
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Creaks,clunks and noise from new bike

Hello everyone,

After obtaining my new bike online from CRC, a couple of weeks have passed and I've been having creaks from the bottom bracket (keep in mind that I'm a clydesdale, now at 270lbs).

I took the bike to the lbs, and they've taken the BB out, greased it, checked it for wear (new) and after installing it, the creaks go away for a few days and return. Sometimes it creaks when pedaling, other times (after servicing) it creaks only when weight is put onto the pedal (starting from a stop) and is okay for the length of the ride.

Since I honestly don't have too much confidence in the lbs (I've NEVER seen him use a torque wrench), what could I check for by myself?

Thanks!
Aris
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Old 10-21-11, 09:16 AM   #2
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I had a new bike that had a BB that seemed to click or creak with every peddle. I was sure it was the crank or the peddle because it happened with every peddle rotation, not every wheel rotation and not randomly. I tightened the arms on the crank with little improvement.

It turned out to be the carbon seat post creaking. Apparently when I peddled I rocked the seat back and forth a little, just enough to make the carbon squeak. FYI: don't grease a carbon post. I found out the hard way. Just make sure it's tight in the seat tube. Also check the clamps between the post and the seat.

good luck
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Old 10-21-11, 09:42 AM   #3
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I would first try to tighten the pedals.
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Old 10-21-11, 10:03 AM   #4
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"FYI: don't grease a carbon post." Use the correct carbon assembly paste. A Web search will yield several sources.
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Old 10-21-11, 10:16 AM   #5
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I would first try to tighten the pedals.
And liberally grease the pedal threads and the shoulder of the axle as well. Also, what type of crank/bb setup are we talking about here? Square-taper, ISIS, Powerspline, integrated...?
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Old 10-21-11, 11:10 AM   #6
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@deermouse: I also thought the suspension stem was the culprit and changed it with a heavy-duty aluminum unit, no change; the LBS also agreed that it was the BB.

@martyr13: done that too..., actually I took the opportunity to swap them with some better quality ones I had... no change again!

@mechBgon: my skills go as far as too describe what I saw taking the BB out of the bike at the LBS; large-diameter housing, square crank axle, the cranks are attached via allen keys instead of the normal sockets cheaper bikes have... the LBS did grease everything... not liberally though, and usually leaving the shop (third visit), the noise starts after a few miles

Edit: it's the first on in the picture (square-tapered)


Last edited by Telly; 10-21-11 at 11:17 AM.
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Old 10-22-11, 09:32 AM   #7
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@deermouse: I also thought the suspension stem was the culprit and changed it with a heavy-duty aluminum unit, no change; the LBS also agreed that it was the BB.

@martyr13: done that too..., actually I took the opportunity to swap them with some better quality ones I had... no change again!

@mechBgon: my skills go as far as too describe what I saw taking the BB out of the bike at the LBS; large-diameter housing, square crank axle, the cranks are attached via allen keys instead of the normal sockets cheaper bikes have... the LBS did grease everything... not liberally though, and usually leaving the shop (third visit), the noise starts after a few miles

Edit: it's the first on in the picture (square-tapered)

Hmmm. A clunking sensation is often caused by the unit rocking around in the frame. That happens when the side with the flange (at the lower edge of your photo) didn't get firmly fastened against the frame. They're supposed to be very firmly fastened against the frame on that side. If the shop took everything apart to grease it, they should've done that as part of the routine.

As you can see, the square-taper crank swedges onto the spindle. If it comes un-swedged and begins to clunk for that reason, and got used that way for any length of time, that arm is probably not going to stay swedged on in the future, because the square hole in the aluminum arm quickly becomes mushroomed out. If that's what's going on, you'd be able to rock the crank around on the spindle by hand.

If your seatpost and frame happen to both be metal, then grease the interior of the frame's seat tube and wipe a thin film of grease onto the seatpost too. You could also grease your chainring bolts, including the exterior surfaces where they contact the rings and crankarms. I've even had bikes where the front derailleur clamp creaked on the frame as it flexed, but those were carbon frames. Start by confirming the FD is clamped adequately snug.
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Old 10-22-11, 10:12 AM   #8
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What brand/model bike? What type of bottom bracket? If you have integrated bottom bracket, there are multiple threads here on problems/fixes. If it is integrated BB, after checking seat post, cable rubs, chainline, etc. you may have to loctite BB bearings in place.
http://www.bikeforums.net/showthread...BB+30+creaking
http://www.bikeforums.net/showthread...+bracket+noise
http://www.bikeforums.net/showthread...+bracket+noise
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Old 10-23-11, 03:35 AM   #9
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@deermouse: I also thought the suspension stem was the culprit and changed it with a heavy-duty aluminum unit, no change; the LBS also agreed that it was the BB.
Quote:
Originally Posted by Telly View Post
Since I honestly don't have too much confidence in the lbs (I've NEVER seen him use a torque wrench)
Quote:
Originally Posted by Telly View Post
... the LBS did grease everything... not liberally though
I'm not sure I understand. The picture you provided of the bottom bracket is of a sealed bearing unit and your description sounds like a sealed unit and any but the cheapest new bikes today will have sealed BBs. Usually with a bad sealed BB you don't grease it, you just replace it. What did the LBS grease? If this is a new bike and the BB isn't sealed it is probably of low quality and you should replace it with a sealed unit. The square taper sealed units just aren't that expensive, if that is really the problem.

It could also be the crank arms connection to the BB if they are not tight enough.

I understand that it seems to be the BB, but since all attempts to fix it have so far failed, you may need to look elsewhere. It could also be the seat itself. Especially an inexpensive seat, but even a better seat may creak or pop with twisting. It would be helpful if you can provide a little more info on the bike itself, brand and model or any other info you can provide.

Last edited by deermouse; 10-23-11 at 04:07 AM.
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Old 10-23-11, 07:04 AM   #10
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I've taken the bike to another LBS which I trust (unfortunately farther away), and he assured me that there's probably no problem with a new bike and BB, and in most cases the BB hasn't been torqued properly, also he's going to change the pedals to better quality aluminum units (although on a quick inspection, he doesn't think they're the culprits). He also showed me a special lube he uses for BB that also has small Teflon particles which act as thread lockers.

Hope it isn't anything more serious than a BB change (heard stories of frames with slightly oversized BB chambers, although this bicycle isn't a Walmart or low-quality unit).
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Old 10-24-11, 04:34 AM   #11
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try lubrication between crank arms and bottom bracket shaft. if two different metals; cranks alloy, shaft steel, this causes the noise
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Old 10-24-11, 04:59 AM   #12
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Just got a call from the 2nd LBS, the BB seems to be absolutely fine, so he's going to clean, re-lube and install/torque it properly.

BTW, I called the bike company (Corratec) and they informed me that the BB is TH BB-7420ST-S (113mm). The LBS says that it's solid, but I think maybe I should change it to something of better quality like the Shimano UN40 which should be compatible.
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