Wobbly cranks/tightening with a household tool?

I had a little crash on my bike, and now the cranks are slightly wobbly. Not much but it's annoying me. Do I need to buy/borrow a tool to tighten them, or is there a household tool my Dad would have in his garage.

I know they're not cottered cranks, they kind of look like a big allen key would do it?

Your Dad should have a tool for this - go into the garage and ask him for his help.

Probably an Allen key.

Your Dad should have a tool for this - go into the garage and ask him for his help.

Probably an Allen key.

Ha. I've just realised the original post made me sound about 8.

Thank you.

I'm not sure 'a little crash' would loosen your cranks Jack.
I would have a good investigate to make sure something hasn't bent.

8mm allen key usually.

I'd be a little worried about how they came loose during a crash. Could have messed up the tapers or something? Can't really help much more than that without pictures of an investigation after removing the cranks. I'm guessing you don't have a crank puller so for now it's probably best to tighten them up and see if it all works / rides OK.

I'm not sure 'a little crash' would loosen your cranks Jack.
I would have a good investigate to make sure something hasn't bent.

A people carrier pulled out from a side road which resulted in me skidding into it, hitting it with my face and coming off the bike. Luckily my worst injury with a tiny cut on my nose and scraped balls? (not sure how that happened).

Ever since the two arms have been just slightly loose - I thought it may have been when I bounced off the vehicle the bike hit the ground funny. I hope it's not serious.

What cranks / BB / bike are you running? Might be worth a trip to your LBS for them to have a quick look over if you don't have the tools to investigate yourself.

I have a Jamis Sputnik, the 2011 model (http://www.jamisbikes.com/usa/thebikes/road/fixies/11_sputnik_spec.html)

Ok so a standard cartridge BB / square taper crank setup.

Tighten up the crank bolts and see what happens. If it still feels loose, it could be that the BB had a knock and is dead. If this is the case, you will see the BB spindle moving with the crank arms when you wobble it. I guess the tapers could have got buggered up, but I think it's pretty unlikely.

What a day for a little test ride!

I have a wobbly crank question:

My crank keeps getting very loose despite tightening, new campagnolo veloce bottom bracket, 2nd hand but previously fine campagnolo xenon cranks, and used crank bolts. Gets so about once a day I have to tighten the left crank up.

Additionally, I have an odd creaking from somewhere, only when pushing down and not when pulling up, tightened up chain ring bolts (what were loose, and noise remained, albeit slightly less).

Any ideas, compatibility issue, not enough HTFU, etc?

if its the square taper sort i had one like this that kept coming loose left hand side had to bin it square taper worn that will also cause the creaking

bin crank or bottom bracket?

ive had this, on two seperate occasions,
remove crank,
apply a fnark load of grease,
put crank back on and tighten like a motherbitch, (use a seatpost as an extension)

its sorted it for me, of course a more informed fellow may tell me this is a foolish thing to do

Sounds like the taper has been deformed, which usually happens by over tightening. Take the crank off and have a look at the outside of where the taper is. If there is bulging, you have a dead crank arm. Alternatively, I guess it could be the BB spindle and deformation should be pretty easy to spot. Not sure there is anything you can do to fix either of these parts, so I imagine you'll need to replace something to get it all right again.

^^ That might work temporarily, but it could be the final nail in the coffin for your already dodgy taper. I don't suppose it matters if it's already gone though.

Sounds like the taper has been deformed, which usually happens by over tightening.

But what is considered over tightening...?
What kind of torque is recommended...?

Until my torque wrench arrives, I go for as tight as a possible by hand then a firm body weight final push down. Is that too much?

Questions.

crank

@Prince - difficult to say if it's "too much" tightening in your case. You may have Popeye's forearms, the grip of a chimpanzee and the body weight of this guy http://www.youtube.com/watch?v=OWxlZ52O0rI
in which case I'd say you definitely are over-tightening. You'll just have to wait for the torque wrench and then look up the pressure needed using t'internet.

But what is considered over tightening...?

If you are using a piece of scaffolding for extra leverage that's probably too tight.

What kind of torque is recommended...?

About 40Nm I think, although I don't have a torque wrench that goes this far so am not speaking from experience. The crank manufacturer will most likely recommend an appropriate torque.

I go for as tight as a possible by hand then a firm body weight final push down. Is that too much?

That's about the same as I do and haven't had any problems yet.

I dont think there is a science to crank bolts, on tour one of my bolts came loose, I didn't have an 8mm key so I just shoved two screwdrivers in there, worked fine. I dont think you need to worry too much about over/under tightening crank bolts on cotterless.

wrong. you should worry just exactly the right ammount, unless you want to fuck yourself and your ride up.

http://www.sheldonbrown.com/brandt/installing-cranks.html

http://www.parktool.com/blog/repair-help/torque-specifications-and-concepts

http://www.zinncycles.com/torque.php

^ Exactly, they vary wildly, and with the age of crabone cranks, really need to be careful.

Also worth noting not all torque wrenchs are equal, some are an utter joke as far as accuracy goes (i.e. should be 30nM, but didn't click out until way way over 100nM, and that was a £65 job).

I'm not sure 'a little crash' would loosen your cranks Jack.
I would have a good investigate to make sure something hasn't bent.

WJPrince is right.
A crash would not unscrew a crank bolt. You might have stripped a thread or something else along these lines.
You should go down to your LBS and have them take the crank off to check for damage. Anything found now could well be cheaply repairable, ride around on it and you'll just compound the damage and could end up needing a new crank-set.
An LBS won't charge much more than a fiver to have a look - ask them first for a price.

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By the way, I always recommend an LBS in these situations because if the person is asking what an allen key is they probably wouldn't be able to spot deformed threads or what to do with them.
It's always good to support the local shop.

It was slightly wobbly because my chain had become a bit slack. Probably needed a tighten with a handy tool from my father's garage though. Thanks for the advice guys.