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Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

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Old 01-29-06, 09:44 AM   #1
Matheus22
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Bottom Bracket Hard Time....

Something "interesting" just happened to my bike and I havenīt found a decent explanation for it neither a good sugestion of what to do to fix it at the bike shops around.

I was using this campy BB, italian thread, 111mm, with a campy Xenon crank. Theyīre working just fine during the last 3 months, but all of the sudden I realized the BB rigth cup was coming out of the frame, and the crank was touching the BB cup. I thougth the frame thread was history, but for my surprise everything look ok when I removed the BB.
After that, I tried to put the pieces together, only to discover that even when the BB was "in the right place" my crank was STILL touching the BB cup.

The impression that Iīve got was that the spindle moved to the left, leaving the right side shorter (Iīll check that hypothesis later this week). I donīt believe that the crank could have pressioned the spindle so hard that it yielded.

Any suggestions of what I should do (specifically, what BB spindle lenght should I look after) to fix this?
The pictures below were taken before the problem, Iīm posting them just so you can see the parts Iīm talking about.
Attached Images
File Type: jpg BB1.JPG (56.7 KB, 12 views)
File Type: jpg BB2.JPG (43.5 KB, 12 views)
File Type: jpg Crank.JPG (44.4 KB, 7 views)
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Old 01-29-06, 09:52 AM   #2
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Italian threaded bb's are notorious for having the right (drive side) cup unthread in use unless they are installed VERY tight. If your bb did this, the resulting play and rocking may have damaged the cartridge bearings and allowed the spindle to shift out of line.

I expect you will have to replace the bb. This time really torque it down to spec and consider blue Loctite to keep it in place.
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Old 01-29-06, 09:57 AM   #3
Matheus22
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So I should stick with the 111mm spindle anyway? After I use the loctite stuff will I be able to unthread the BB if I need it? I donīt know much about this stuff, so I get a bit insecure (wich does NOT mean I donīt trust you, people here at BF always helped me)
Thanks a lot for your help!

Last edited by Matheus22; 01-29-06 at 10:03 AM.
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Old 01-29-06, 10:00 AM   #4
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Quote:
Originally Posted by HillRider
This time really torque it down to spec and consider blue Loctite to keep it in place.

I agree 100%, - installation torque is very important. I don't have experience with Italian threading, but often, the installation torque is more than you'd expect. Also, I am not a big fan of Loctite if installation torque is sufficient to keep the parts in place. It could make future removal a headache.
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Old 01-29-06, 10:51 AM   #5
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Blue Loctite (Grade 242) is a very effective thread locker but allows disassembly without heat. You will be able service the bottom bracket in the future but it shouldn't unthread by itself if the installation is done properly.

The installation torque spec is VERY high and that plus the Loctite should prevent future problems. Loctite really shouldn't be necessaty but it is a good safety precaution.
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Old 01-29-06, 11:20 AM   #6
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Thanks a lot hillrider. I wonīt have much trouble finding a Campy 111mm italian thread BB, but anything diferent would be almost impossible for me to find. I would have to import...
Iīll use the Loctite 242 and WATCH the mechanic install it, so I can make sure itīs the right torque. Since Iīm not planning having to remove the BB so soon, Iīll use the loctite as a safety precaution like you said.
Two bike shops and lots of calls to bike shops from São Paulo later, I get decent advice from you here in bike forums. You guys are great, thanks again!
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