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Posted

Mine was doing the same and took my bike (road) to the LBS and they tightened the BB. it lasted a week and it started again. They then replaced the BB and it lasted a full week again. Taking it back again this week.

 

So... make sure of your LBS. Cry

Posted

read in a magazine that when your juice bottles leak down your down tube and drips into the bb. This also causes this creaking. Just read this in bicycling, dont know if its true or not. They say just clean well after every ride. Iv never had this problem with my external bb on a mtb. just was after every ride

Posted

Creaking BBs are not the fault of your bike shop. It is a design fault. The bike shop can just make it go away temporarily by cleaning and greasing it But soon new dirt ingresses and you're back to square on. Creaking BBs will be with us until bike designers do away with the puny little BB cup. Most of the advice here about cleaning and regreasing is right and just about all you can do.

 

BBs, pedals and quill stems all have so-called dynamic joints. This is just a fancy word for a crappy joint that moves during operation.

 

To experience the movement for yourself, feel the huge play between pedal and crank when the pedal isn't given its final 1/2 turn. Same goes for a BB, it moves signficicantly until we attempt to disguise the movement by tightening it. However, metals being elastic simply deform under force and the movement reappears in operation.

 

Such movement is evident when you examine the pedal interface on any crank that's been used for a while. You can see how the pedal chewed into the crank. That's not from tightening, but from moving around.

 

Same for a BB. If you take off a creaky BB you'll notice the aluminium oxide on the parts of the thread where the BB deformed and the two surfaces fretted against each other.

 

A solution to the pedal problem could be a taper interfaces such as on a car's wheelnut. That joint never moves. Another solution could be a pinch-botl arrangement such as on threadless stems and new cranks where the left crank is pinched onto the BB spindle.

 

 A pinch-bolt on an oversize BB cup would solve two problems: BB creak and BB weakness. We really need a much bigger cup so that we can get a big beefy bearing on there. The small bearings found on today's external bearing BBs are a joke.

 

For now, get a BB tool, remove your BB from time to time and clean and grease it before reinstallation. There are many solutions - all temporary. You can use grease, copper compound, Teflon (plumber's) tape, loctite or lard. The outcome is the same - temporary relief.

 

 

 

 

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