My crank keeps undoing itself.

and it also helps to be slightly drunk.

ro-LAND Mash, the same thing happened to me. I thought that the crank had just got loose, and retightened it. From that point on, it would loosen very quickly.

Basically I had worn down the 'square' on the BB so that needed to be replaced. The crank arm is now my office paperweight...

So, just to check. will I need a new BB, or just a new crank arm.?

I'd replace both.

Likely just a crank arm, the harder material of the BB spindle is very hard to deform.

Think I'll ignore Kowalski's advice - it took him about 4.5 centuries to get a bike on the road ;-)

And after all that I ended up with a CONdor.

But mine goes. ;-P

I'd check the threads and make sure they aren't gone.

I'd watch out for locktite also, I once locktited my nuts onto the axle and when i got a puncture and had to undo said nuts, they took the threads clean off leaving me with a fucked axle.

CHUG_IT I once locktited my nuts onto the axle and when i got a puncture and had to undo said nuts, they took the threads clean off leaving me with a fucked axle.

Yeah but that was just plain silly. :p

yes it was

I'm not locktiting my nuts to anything.

dogsballs [quote]Sam I'd take the crank off using a crank extractor (Halfords sell one for about a fiver if no-one has one to lend), degrease the BB spindle and the crank area where the spindle enters, do a light re-grease back on the spindle and reassemble.
Give it a week and retighten the crank bolt if required, then (touch wood) all should be well!

you should never lube a spindle!![/quote]

I'm in the 'apply a very thin wipe of grease to the spindle' school of thought. That's what my LBS did and that's what I do. It's a personal thing. Me and my lube.
I've never had cranks loosen/fall off (well once of my dad's bike but that was cottered and non-maintained).

I do it because I don't want it to bond and be unremovable. Only the thinnest amount of grease though, just to prevent bonding.

Same hear. Just a SMEEAR®

hippy [quote]dogsballs [quote]Sam I'd take the crank off using a crank extractor (Halfords sell one for about a fiver if no-one has one to lend), degrease the BB spindle and the crank area where the spindle enters, do a light re-grease back on the spindle and reassemble.
Give it a week and retighten the crank bolt if required, then (touch wood) all should be well!

you should never lube a spindle!![/quote]

I'm in the 'apply a very thin wipe of grease to the spindle' school of thought. That's what my LBS did and that's what I do. It's a personal thing. Me and my lube.
I've never had cranks loosen/fall off (well once of my dad's bike but that was cottered and non-maintained).[/quote]
you put cranks on....haha!

Yeah.. on your mum.. before I rode her so hard her false teeth fell out.

argh, you're the dud root she had!!

but c'mon, get off my mum, as i just got off yours!

i don't play fair and your mum is hotter than mine so i'm going back for seconds..

Hmmm, MILF. Mercian I'd Like To Fix.

well if you did it properly the first time there'd be no reason to go back! doesn't bother me, gives me more time with mal!

Ha! She'd rip you apart little man :P

didn't rip me apart.....;o)

hippy Ha! She'd rip you apart little man :P

she can try all she wants. i'm a man, spelled M A N! not bag of spuds :p

I use a hex bolt that came with my miche cranks and the socket wrench on the end of my pedal spanner. tighten it up real tight, then take it out and put the allen key screw with the dust cap in there instead. never had the problem since.

hippy [quote]dogsballs [quote]Sam I'd take the crank off using a crank extractor (Halfords sell one for about a fiver if no-one has one to lend), degrease the BB spindle and the crank area where the spindle enters, do a light re-grease back on the spindle and reassemble.
Give it a week and retighten the crank bolt if required, then (touch wood) all should be well!

you should never lube a spindle!![/quote]

I'm in the 'apply a very thin wipe of grease to the spindle' school of thought. That's what my LBS did and that's what I do. It's a personal thing. Me and my lube.
I've never had cranks loosen/fall off (well once of my dad's bike but that was cottered and non-maintained).[/quote]

I have always applied a layer of copper ease to the spindle and another layer to the threads on the bolts, and have never had a problem (either with removing them, or with them seizing).

31trum didn't rip me apart.....;o)

She was happy to leave you sleep, soft man.