# Bottom Bracket Keeps Coming Loose



## Fai Mao (Nov 3, 2008)

I keep having the left side of my bottom bracket come loose. I take the crank arm off, tighten the cup down to specs, replace the crank arm and 300 miles or so later it is loose again.

It's a new bottom bracket. I don't want to simply replace it. I bought it while on a tour in another country so I cannot simply take it back to the shop.

Any suggestions for kepping it tight?


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## Uprwstsdr (Jul 17, 2002)

I was having the same issue after having my bottom bracket overhauled. I took the cup out and put a generous amount of Blue Lock tight on the threads, they have held since. You can also try teflon plumbers tape.


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## Indyfan (Mar 30, 2004)

I'd go with the thread lock compound if you're having that much trouble. Usually, a generous coating of some Phil grease or Park grease will be sufficient. For noisy BB's I use anti-sieze. Teflon tape is OK, but I've never really liked using it in that application.

Bob


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## OES (Jan 23, 2002)

Fai Mao said:


> I keep having the left side of my bottom bracket come loose. I take the crank arm off, tighten the cup down to specs, replace the crank arm and 300 miles or so later it is loose again.
> 
> It's a new bottom bracket. I don't want to simply replace it. I bought it while on a tour in another country so I cannot simply take it back to the shop.
> 
> Any suggestions for kepping it tight?


What they said, plus it's possible your torque wrench is bung out of spec. I had that problem with a Phil BB, using their own thread lock. I ended up just trying a different torque wrench and immediately knew what the problem was. I was undertorqing.


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## jacks6514 (Apr 12, 2009)

Be cautious when using teflon tape on certain applications as it will allow for over tourqing and can result in cracked housings. I would use the medium strength blue locktite compound as you may want to remove it another day.


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## FatTireFred (Jan 31, 2005)

jacks6514 said:


> Be cautious when using teflon tape on certain applications as it will allow for over tourqing and can result in cracked housings. I would use the medium strength blue locktite compound as you may want to remove it another day.




I can't imagine that the increase in torque achieved when using teflon tape will be so much to crack the bb shell. or did you mean cartridge bb housing? still... and ftr, I don't rec teflon tape anyway


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## danl1 (Jul 23, 2005)

I would suggest checking that the faces of the shell are clean and square, or simply having them faced to be sure. Locktite, etc. can help and aren't inappropriate insurance, but better to do the job right. With a properly prepared shell, a bit of grease and proper torque is all that's needed - any locking compound is simply a belt over the braces.

Teflon tape is a sealant, not a locking compound. Unless the cycle is being used for something I'd rather not be party to, it has no proper place on a bicycle. Sure, it might temporarily stop a creak, and it can occasionally help prevent certain metals from seizing together, but there are better ways to accommodate both goals. It's perfectly lousy as a thread locker, as the 'teflon' part would suggest.


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## DaveG (Feb 4, 2004)

*odd*



Fai Mao said:


> I keep having the left side of my bottom bracket come loose. I take the crank arm off, tighten the cup down to specs, replace the crank arm and 300 miles or so later it is loose again.
> 
> It's a new bottom bracket. I don't want to simply replace it. I bought it while on a tour in another country so I cannot simply take it back to the shop.
> 
> Any suggestions for kepping it tight?


I've had Italain BB come loose on the drive side but I've never seen the left side loosen on a BB. Unless you are using a completely inadequate amount of force I would think there could be a thread or facing issue. The pedaling force should tighten it. What type of BB?


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