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I am putting together a Cross bike (SOMA). During a test spin last Sunday, the ISIS bottom bracket broke off at the left pedal, sending me to the pavement. Pictures are attached (of the BB that is). The bike and all the drive train components are brand new; everything had 10 miles or less on them. The BB was spinning freely, it was not loose in the frame, nothing out of the ordinary.

Interestingly, Sheldon Brown has a note on a similar problem on his website, http://www.sheldonbrown.com/fsabb.html. My BB has a different brand name on it, but it sure looks like it was put out by the same factory.

Anybody have experience with this type of failure?

-Kalukis
 

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Well, what's the brand name? And what material was the BB axle made from? I think there have been some issues with some scandium BB axles, such that people have been advised to use longer fixing bolts. Can't really comment on your issue, though, since you've given no info on the BB.
 

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That's scary. My new bike has FSA carbon cranks with the ISIS BB! I haven't had it on the road yet.

Edit: Actually it's a truvativ ISIS BB, not FSA.
 

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imetis said:
That's scary. My new bike has FSA carbon cranks with the ISIS BB! I haven't had it on the road yet.

Edit: Actually it's a truvativ ISIS BB, not FSA.
Huh, I remember hearing about this a year or two ago with the FSA Ultimax BBs. Thought that was taken care of a long time ago. Pretty scary, not something I want to be worry about when I'm sprinting to the finish line :( . Notwithstanding, get that BB warrantied.
 

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Manufacturing defect

These photos show a very obvious manufacturing defect. The hole through the hollow spindle is supposed to be go directly through the center of the spindle, so the spindle has a constant wall thickness. But these photos show that the hole is off-center. In the top photo, the wall thickness on the right is clearly much thinner than on the left. In the bottom photo, it can be seen that the wall thickness at the bottom is much thinner than at the top. This lopsided wall thickness could easly cause the spindle to buckle and shear off under a high load.

It's hard to tell from the photos whether it is simply a case of the hole through the middle is off-center, or whether when the hole was formed it was mishaped, leaving the wall on one side too thin (depends on the manufacturing process). In either case, there is clearly a problem in the manufacturing process involved, and the spindle is defective.
 

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That is a very uneaven distribution of metal! I wonder if this is one of those parts that is rumored to be made by orphans in china throwing molds in the air while the metal is still liquid?
 

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It does appear to be a manufacturing defect ...

so tell us the make and model of the BB and how this whole thing is resolved. It's posting this type of information that lets others know there is a potential problem with a product. If it is one of those one in a thousand defects that's one thing. If yours is an early failure of a new model, others need to know before it happens to them.
I would suggest sending the info to the manufacturer to get their opinion on it. They too need to know they have a potential problem.
 

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imetis said:
That is a very uneaven distribution of metal! I wonder if this is one of those parts that is rumored to be made by orphans in china throwing molds in the air while the metal is still liquid?
Yeah, I guess one got distracted by slogans as “It is strictly prohibited to touch the wire which has 50,000 voltage and causes death upon contact. Violators will be penalized!”.
 
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