Left crank keeps unscrewing

[zimzum42]

Bit of a problem with the fixie. Left crank keeps falling off.

Kept screwing it back on tight, but gave up yesterday as had to stop every few hundred yards to screw it back.

Dismantled the whole drive train and noticed the right hand crank was a bit loose too. Could this be the problem?

Also, I have a little bit of a slack chain, might this be the cause?

The threads seem fine, and the BB seems fine too.

Any ideas?

 

[hubgearfreak]

once they start to come loose again & again like this, it's because the tapers are knackered. sadly, it's new cranks time i reckon

 

[spandex]

yep HGF thats spot on its time for new cranks sorry mate.

 

[zimzum42]

Do I need a new BB though?

 

[mickle]

Do I need a new BB though?

No.

 

[spandex]

Hello mickle how are you doing?



Mickle is right you dont need a new bb

 

[02GF74]

^^^^ wot they say.... but depends on how worn the square hole is.

I had thsi happen on my mountain bike - left crank becoming lose - happened a 2 or 3 time. I glued it on with epoxy and tightend the bolt a littble bit more than normal and had not problems with it - must have done this about 10 years ago and it is my dialy commuter!!! it'll be interesting come bottom bracket replacement time!! bit I reckon a bit of heat - alloy exapand more thant steel it will come off.

 

[mickle]

Hello mickle how are you doing?



Mickle is right you dont need a new bb

Of course I'm fricking right, get back to work.

 

[spandex]

Gluing is not a good idea as a new set of cranks £30ish minimum (now) or Glue it and then when the time comes to change them it will be £30 cranks + £17 new BB + £40+ for the labor = £80+ if you Glue OR £30 if you change them now!.

 

[spandex]

Of course I'm fricking right, get back to work.

WORK WORK don't you swear at me I'm off work till Mrs Spandex heads off tomorrow to the U.S.A. for 3 months.

 

[mickle]

Give her one from me.


I hug I mean obviously.

 

[bobg]

Bit of a problem with the fixie. Left crank keeps falling off.

Kept screwing it back on tight, but gave up yesterday as had to stop every few hundred yards to screw it back.

Dismantled the whole drive train and noticed the right hand crank was a bit loose too. Could this be the problem?

Also, I have a little bit of a slack chain, might this be the cause?

The threads seem fine, and the BB seems fine too.

Any ideas?

Hoe this doesnt sound insane but I had an old bike that was doing that adter I'd "restored"it and found I'd put the bottom bracket on the wrong way round hence the thread was working loose as I pedalled

 

[Riding in Circles]

We had this on a newish crank in the workshop once, cleaned all the threads and used a medium threadlock and no problems since, also it will still come apart with the right tools.