BB30 - Left crank keeps falling off!

[Yellow Saddle]

It sounds like you’ve got a stripped thread. Check the bolt first, if that’s okay, you’ve stripped the thread, and, although you could re tap the thread, it’s probably better to get a new crank.

You can't retap a thread that's been stripped. Once the material is gone, it is gone.

 

[Yellow Saddle]

Could I get a left arm crank only? Would that work, if indeed I have got a stripped thread? I only ask because 46/36 fsa cranks are like hens' teeth!

I doubt you'll get a left crank only. First, determine if the thread is indeed stripped. Is there loose thread material on the bolt?
Do you understand that the crank goes on with press-fit resistance, which could explain what you experience when you said "it becomes looser again"?

Once you've ascertained that the crank is damaged, don't bother getting another FSA BB30 crank. It is absolute rubbish. Try and convert to Hollowtech or, get a crank that attaches to the spindle via a pinch bolt, not a centre bolt.

 

[grellboy]

I doubt you'll get a left crank only. First, determine if the thread is indeed stripped. Is there loose thread material on the bolt?
Do you understand that the crank goes on with press-fit resistance, which could explain what you experience when you said "it becomes looser again"?

Once you've ascertained that the crank is damaged, don't bother getting another FSA BB30 crank. It is absolute rubbish. Try and convert to Hollowtech or, get a crank that attaches to the spindle via a pinch bolt, not a centre bolt.

Got that right. Now on 3rd crankset in two years!!

 

[Yellow Saddle]

Got that right. Now on 3rd crankset in two years!!

All three FSA? Same problem?

When you descend, standing on the pedals with the crank horizontal, do you stand Regular or Goofy?

 

[Racing roadkill]

You can't retap a thread that's been stripped. Once the material is gone, it is gone.

You can tap it larger, and use a larger bolt.

 

[Yellow Saddle]

You can tap it larger, and use a larger bolt.

That's not relevant in this case. The hole is something like 14mm with a special aluminium bolt that's no longer than 14mm. Not readily available.