Loose Crank Arm Problem

:( Maybe I'll just have to bite the bullet and change for a square taper...

It's not staying tight because you probably overtightened it or undertightened it the first time.

Overtighten = fucked
Undertighten + ride = fucked
Correct = years of fine service.

Square taper is not the answer. Correct installation is the answer.

Balls... although I didn't install it originally, had the shop assemble it for me... think I can take it back to them like that and ask for answers??

Cranks generally don't come loose by themselves. How long have you had them ?

Say a year almost but realistically they've not had a years use, probably equivalent of 3 months solid use

grrrr. I feel your pain.

I don't assemble cranks to bottom brackets precisely for this reason. Imagine a Campy Record carbon double chainset coming loose on the BB and you find both are u/s after becoming loose, the bill will be about £420. Let someone else do it and throw it back with suitable expletives and a lawyer.

So I'm having the same problem as the OP, left crank keeps coming loose. Except it isn't coming out horizontally, it just has about 10mm rotational play no matter how hard I tighten the bolt. Cranks fitted by BLB about a month ago with a brand new BB. Fucked?

Possibly. Surely the best people to tell you would be BLB themselves.

Aluminium alloy crank v steel bottom bracket axle. Only one winner every time. Always re-tighten after some initial use from new. Even carry tightening tool with you on first ride...

Possibly. Surely the best people to tell you would be BLB themselves.

BLB confirm. Fucked. At a time when I do not need this. So, anyone got any cheapish cranks for sale?

did BLB use the old anglegrinder customization treatment on your cranks as well then

BLB confirm. Fucked. At a time when I do not need this. So, anyone got any cheapish cranks for sale?

I know it would be hard to prove that you haven't touched it(you haven't, have you?), and judging from their level of grumpiness, but isn't BLB responsibility to replace something if they didn't fit the part right?

hi all

my left hand crank bolt keeps coming loose - only just built this bike and 1st proper ride (about 15 mins) it was so loose the bolt came out by hand. Stopped at evans and tightened.

Then yesterday went out for about 30 mins and it started to creak then when i got home noticed it was really loose again.

Could it be my bolts aren't long enough? I just went into condor and they gave me these Allen key bolts - no idea if you get diff lengths?

I read some1 mentioning Locktite - think that will sort it ?

thanks
sam

I had this. Just get a really really long tool and tighten them so much that they will never come off again. Haven't come loose since. Whether I iwill be able to remove them, should I so wish , is another matter :)

well my allen key is about as long as its going to get i think :) - but ok ill try tightening as tight as i can

these are the type of bolts i have btw (if makes any difference)

1 Attachment

usain?

Tighten the fuck out of it.
You should only have to do this once.
If the bolt keeps coming loose after this it means you fucked the taper inside the crank.

A really good way to get sufficient leverage on the bolt is to grab the allen key and crank at the same time and push each towards the other with your body weight forcing both sides down.

This has always worked for me.

Newly installed cranks, move up the axle during the first couple of rides. This results in the bolt loosening. Just tighten it up again, eventually the cranks will stop moving. I would'nt recomend you keep over tightening though, as you will likely mis-shape the inside surface of the crank arms.

Nope, check Sheldon.
We've been through this before.

Tighten the fuck out of it the first time and you will never, ever have problems.

does feel familiar.

History repeating..

Nope, check Sheldon.
We've been through this before.

Tighten the fuck out of it the first time and you will never, ever have problems.

Dependent on materials used you can fuck the taper, I destroyed a royce/sugino75 by over tightening. As long as you dont have an overly long leverage on your allen key, anything greater than 15cm then tighten it as much as you can by hand. Also try a good quality anti-shake/locktight.

http://www.londonfgss.com/thread23425.html

Tighten the bolts (with a resonable amount of force, but I would'nt 'put my weight into it'). Ride the bike a few times and retighten. The cranks work their way up the taper after a couple of rides because of the torque on the bolts.

Tighten the fuck out of that bolt, then get someone who knows what they are doing to have a look at it just in-case.

The quote I found then was good. :)
http://www.londonfgss.com/post742009-11.html

Just to be absolutly clear.
Tighten well once. Then just take the slack out after a couple of rides.