Bicycle Mechanics - Need help with Centaur bb--I think

Background: I was getting a light clunking noise and vibration from my Campy Centaur bottom bracket. After tightening everything up in the area, the bb seemed to be the culprit by the process of elimination. So I bought a new Centaur black bb.

The current problem: I installed the new Centaur bb, using the torque wrench to make sure that everything was tightened properly. I went out on a test ride, aaaaaaaaaaannnnnnnnnnnndddddd it's still clunking with the new bb.

BTW, this clunking is intermittent--no real pattern, but happens most of the time. It's most apparent when I'm going up hill or riding out of the saddle. There is no clunking when the bike is on the rack and I am pedaling it with my hand.

Does anyone know what the problem is and how to fix it?

Thanks,

Rich

PS: I do have successful experience changing bottom brackets, but only with Shimano Ultegra.

Are you SURE you eliminated the pedals as the source of the noise? How about the chainrings?

Check your BB housing on the frame for cracking. I have only seen that once but you won't know until you check. Clean the threads and shine a light obliquely on the parts. It will be obvious. What is the frame material just out of curiosity?

What is the frame material just out of curiosity?

Steel

Background: I was getting a light clunking noise and vibration from my Campy Centaur bottom bracket. After tightening everything up in the area, the bb seemed to be the culprit by the process of elimination. So I bought a new Centaur black bb.

The current problem: I installed the new Centaur bb, using the torque wrench to make sure that everything was tightened properly. I went out on a test ride, aaaaaaaaaaannnnnnnnnnnndddddd it's still clunking with the new bb.

BTW, this clunking is intermittent--no real pattern, but happens most of the time. It's most apparent when I'm going up hill or riding out of the saddle. There is no clunking when the bike is on the rack and I am pedaling it with my hand.

Does anyone know what the problem is and how to fix it?

Thanks,

Rich

PS: I do have successful experience changing bottom brackets, but only with Shimano Ultegra.
I have one of the new Centaur BB's and it's flawless. As far as your problem goes, I knew someone that had a similar problem. It seems that he was ever so slightly back pedaling or pausing during his stroke. It have the illusion of a clunk. If you pedal the bike by hand on a stand then stop just for a second then continue to pedal you can feel it. It sounds crazy but it sounds just like what you are expeniencing. Very Simple to fix, pedal smoother! LOL

Tim

I have one of the new Centaur BB's and it's flawless. As far as your problem goes, I knew someone that had a similar problem. It seems that he was ever so slightly back pedaling or pausing during his stroke. It have the illusion of a clunk. If you pedal the bike by hand on a stand then stop just for a second then continue to pedal you can feel it. It sounds crazy but it sounds just like what you are expeniencing. Very Simple to fix, pedal smoother! LOL

Tim

I will check that out, but why doens't it happen on my Ultegra-equipped bike or my ancient Suntour-equipped bike?

Rich

The two places I'd look at after the bottom bracket would be the headset and the wheels.

I think I've found the sources of the noise--THE CHAIN! Last night I went to the Park Tool site to see if they any insight. They said that a tight link could be a noise problem. This morning, when I was following their directions to find a tight link, I discovered that the openable master link I am using caused a slight hesitation when it passed over one or the other jockey wheels. I could feel slight vibration in the pedal when it passed. Probably would be worse under pressure. I did not think that this would be an area of problem since I have used SRAM power link chains on my other bike for years with no problem.

The problem is the masterlink by Forster for Campy 10-speed chains. It's just not quite right. A LBS suggested it and sold it to me. Up to that point I had had my chains changed as part of general servicing by the shop that built my bike. They did not treat me very well back in the summer and I decided that I would change my own chains. I did not realize that Campy chains require a $100 tool for installation. When I called the closest bike shop they said that they could install the chain for 10 bucks or sell me the masterlink for the same amount. I made the mistake of going with the latter. In hindsight, I would have saved money by buying the Campy tool. But the process of discovery has been fun in annoying way.

Thanks for all your suggestions.