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Old 05-12-06, 10:59 AM   #1
Metaluna
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06 Centaur BB spindle feels tight

I just installed a new 2006 Centaur bottom bracket on my Bianchi (68mm BB shell, 111mm spindle, English) to replace a Veloce AC-S. Even out of the box I noticed that the Centaur spindle had much more rotating resistance than the AC-S (which has about 2000mi on it). For example I could spin the bare AC-S spindle with my fingers and it would go for several rotations, whereas the Centaur would barely do one, though it does rotate smoothly.

But of more concern is that the resistance of the Centaur spindle goes way up after I tighten the non-drive-side cup to the recommended 70 n*m/50 ft*lb torque spec. As per the instructions I backed off the torque to around 30 ft*lb and secured the threads with blue loctite, but even at this torque level the spindle is significantly tighter than before. I finally settled at around 10 ft*lb which was a sort of uneasy compromise between tightness of the cup and tightness of the spindle.

So my question is, is this normal? I haven't ridden the bike yet, and I don't want to damage the BB bearings, so I wouldn't mind backing off the torque of the non-drive side cup even more. Could there be something wrong with my BB shell or the BB itself? Is it safe to ride the bike with such low torque on the non-drive side?
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Old 05-12-06, 11:29 AM   #2
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I don't understand how the cup tightness could have anything to do with the spindle tightness. This is a cartridge, yes?
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Old 05-12-06, 11:51 AM   #3
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Quote:
Originally Posted by genericbikedude
I don't understand how the cup tightness could have anything to do with the spindle tightness. This is a cartridge, yes?
Yes. I believe there are 3 cartridge bearings, with one that looks like it presses directly against the non-drive-side cup. I imagine that this cup compresses the cartridge, causing it to bind under torque. The manual actually mentions that this might happen and tells you to back off on the torque. Hopefully there isn't something wierd about my BB shell.
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Old 05-12-06, 12:00 PM   #4
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You might want to see if the shop has another Centaur to check against.

I have a 2 of the AC-H BBs. They are super smooth.
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Old 05-12-06, 04:55 PM   #5
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I just installed a Chorus cartridge bearing bb on a new bike and it came out of the box somewhat stiff also. It's the nature of the beast and they will loosen up after a few hundred miles. Cartridge bearings, due to the seals, will never be quite as free rotating as a cup-and-cone bb but they are very durable.
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