BB30 - Left crank keeps falling off!

[grellboy]

Happened three times now, just seems to unwind itself and then fall off! Put it on really tight again and then still happens. Is it because the thread will have stripped off? If so, what would be the solution?

 

[Smokin Joe]

Is it square taper or Hollowtech?

 

[Cycleops]

What about using some threadlock?

 

[Sharky]

I had that a few months ago with a square taper LH crank.

I had been swapping them from bike to bike, but didn't bother cleaning the threads properly. When I finally did, I found a fragment of something that was stopping the bolt from being screwed in all the way. Cleaned it properly and put it back and has been OK since.

 

[Yellow Saddle]

Happened three times now, just seems to unwind itself and then fall off! Put it on really tight again and then still happens. Is it because the thread will have stripped off? If so, what would be the solution?

What part is unwinding itself?

Stripped thread is easy to diagnose. If you can't, I suggest take it to a bike shop.

 

[Racing roadkill]

Make sure you’ve side loaded the tension of the cranks using the little plastic deely and the plastic tool that comes with most HT2 tools, before you tighten the bolts on the crank.

 

[grellboy]

What part is unwinding itself?

Stripped thread is easy to diagnose. If you can't, I suggest take it to a bike shop.

Just as I pedal I feel the crank getting loose where it screws into the opposite part - the long barrel part that comes on the drive side part of a BB30 crankset.

 

[Nibor]

are you sure it is BB30 and not a GXP if the left hand crank is held on with one bolt?

 

[MontyVeda]

I used to have a similar issue... turned out I wasn't getting enough torque with a standard short alen key so bought some longer ones. It solved it for me.

 

[Cycleops]

Make sure you’ve side loaded the tension of the cranks using the little plastic deely and the plastic tool that comes with most HT2 tools, before you tighten the bolts on the crank.

I'm not sure if it's a shimano crankset, more likely a FSA like this. Perhaps the OP could make it clear;

 

[Nibor]

I'm not sure if it's a shimano crankset, more likely a FSA like this. Perhaps the OP could make it clear;

View attachment 483695

If it is they require a serious amount of torque

 

[grellboy]

I'm not sure if it's a shimano crankset, more likely a FSA like this. Perhaps the OP could make it clear;

View attachment 483695

FSA. 46/36. So clean it up properly and give it some serious effort?

 

[grellboy]

Btw, just tried cleaning thread and reapplying. Gave it some - but not too much - and now the bolt gets to a certain point of tightness, then slips to become looser again. Is it now completely knackered?

 

[Racing roadkill]

Btw, just tried cleaning thread and reapplying. Gave it some - but not too much - and now the bolt gets to a certain point of tightness, then slips to become looser again. Is it now completely knackered?

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.

 

[grellboy]

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.

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!