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Old 07-02-11, 04:37 PM   #1
Glottis
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Bottom bracket removal question

Hi,

I just removed a cartridge BB. I started with the drive side, which took a lot of torque to unscrew. Once I finally removed the drive side cup (and banged my head against the frame), I thought I was going to spend a lot of time to remove the left one, too. However, it was too easy to unscrew it. My 5 year old daughter could have unscrewed it.

Is that normal?

I'm asking because I suspected the BB to be lose, that's why I decided to remove it. There was a sound whenever I pedalled uphill. Sheldon Brown helped me pinpoint the cause:

Quote:
Bottom Bracket Cups/Retaining Rings Loose?
[...]
Turn the cranks so that the left crank is alongside the seat tube, wrap both hands around the crank and seat tube ans squeeze the crank hard toward the seat tube.

Then turn the cranks so that the right crank is alongside the seat tube and repeat this. Listen for a creak/click.
Taken from here: http://sheldonbrown.com/creaks.html

The bike is one year old with only about 1500 Km / 1000 miles, and there was no rust or anything.

Thanks.
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Old 07-02-11, 04:49 PM   #2
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Yes, with a cartridge BB the right side bottoms against the frame, and the left bottoms against the central cartridge and through it to the right cup. You removed it the hard way, doing the right cup first, since you were fighting both the pressure of the frame and that of the cartridge. When installing the replacement, tighten the right (flanged) cup first, then the left.

If neither cups are flanged, like Phil Wood, the sequence doesn't matter since the cups only lock to each other through the cartridge. This design allows you to float the unit s bit to either side of center to adjust the chainline.
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Old 07-02-11, 07:06 PM   #3
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Quote:
Originally Posted by FBinNY View Post
Yes, with a cartridge BB the right side bottoms against the frame, and the left bottoms against the central cartridge and through it to the right cup. You removed it the hard way, doing the right cup first, since you were fighting both the pressure of the frame and that of the cartridge. When installing the replacement, tighten the right (flanged) cup first, then the left.
+1, it's normal. However, removing the drive-side first is preferred despite the "difficulty". If the nds cup is plastic as on some Shimano cartridges, its essential to remove the drive side first. Trying to remove the plastic nds cup while it's under pressure is a guaranteed way to split it. Guess how I know.
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Old 07-02-11, 07:35 PM   #4
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At work, I remove tons of cartridge BBs, almost always starting with the non-integrated plastic cup, if it happens to be plastic. I don't have a problem with splitting them, or I certainly wouldn't do it that way, so YMMV I guess

Anyway, grease everything liberally and make sure the side with the flange is very tight before snugging down the other cup moderately tight. Banging your head on the frame is strictly optional
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Old 07-03-11, 03:28 AM   #5
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Thanks for the replies.

Both cups are metal. Next time I'll start with the non-drive side. Reinstalling the BB was a lot easier. I cleaned all the threads, applied grease, installed the side with the flange first.

Quote:
Banging your head on the frame is strictly optional
I was thinking about shooting a video of my first BB removal, then got lazy. That would have been a very funny video! One moment I was putting all my weight on that wrench. Next moment my head was on the frame, and my glasses nearly flew off my face. I started laughing until I remembered the camera wasn't on.
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Old 07-03-11, 11:38 AM   #6
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Originally Posted by mechBgon View Post
Anyway, grease everything liberally and make sure the side with the flange is very tight before snugging down the other cup moderately tight.
I expect that's the answer right there. The cartridge I removed and damaged the plastic cup by removing it first had been installed with both sides very tight and the plastic cup under a lot of compressive load. Removing the drive side first takes the force off the nds cup and it was then removed with no trouble.
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Old 07-03-11, 11:49 AM   #7
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Originally Posted by HillRider View Post
I expect that's the answer right there. The cartridge I removed and damaged the plastic cup by removing it first had been installed with both sides very tight and the plastic cup under a lot of compressive load. Removing the drive side first takes the force off the nds cup and it was then removed with no trouble.
Is that only for plastic cups? I tightened both sides equally to recommended torque. Should I remove the crank again and loosen the left side cup (without flange) a little bit to prevent problems removing it in the future?
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Old 07-03-11, 03:44 PM   #8
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Originally Posted by Glottis View Post
Is that only for plastic cups? I tightened both sides equally to recommended torque. Should I remove the crank again and loosen the left side cup (without flange) a little bit to prevent problems removing it in the future?
If both cups are metal, you are fine. Plastic cups are the only type you have to be careful with.
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Old 07-04-11, 07:37 AM   #9
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If both cups are metal, you are fine. Plastic cups are the only type you have to be careful with.
Thank you.
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