I need to remove a square taper crank. I had a half-hearted attempt last night using the socket on a crank puller tool and a 17mm spanner (on the flats of the crank puller). However, I couldn't get the bolt/nut to move. Does it require brute strength? As a cyclist I don't have a lot of that, and I'm wary about popping a rib or skinning my knuckles!
I stood over the bike and tried to lever down on the spanner to loosen the bolt while holding onto the pedal on the left hand crank to prevent the crank from rotating.
I was thinking about looking for a long piece of pipe I could use over the end of the spanner to act as a lever, but thought I'd better ask for advice first…!
Yes, get a bigger (longer) lever. 3ft of scaffold pole, for example.
Or whack the spanner with a mallet.
How long have they been on without being removed / greased? May be electrolytically bonded by now..... might be worth a trip to the LBS if brute force is still not working.
My usual method is to go at the crank with a mallet.
Well, it's a bit more scientific than that; there's boiling water and a brick involved, too!
Thanks. They've only been on for a few months - the previous owner fitted them just before I bought the bike, and I've only used it on the turbo trainer, so it's not been exposed to the elements.
Is it a three-handed job to hold the cranks steady, and the spanner on the puller while whacking the spanner with the mallet?
They can be a bit tight. Often made worse by not being able to get the spanner at a good angle to the crank. The best is to get the spanner and the crank to form a V then squeeze the two together.
The cranks should not be moving?
You've undone the bolt that holds the crank on first (normally an 8mm allen key job)?
However, I couldn't get the bolt/nut to move.
what bolt / nut are you referring to here?
It's the bolt which holds the cranks on. The crank puller has the crank puller on one end, and a (12mm or thereabouts?)socket on the other which I'm using to undo the bolt. It's a bolt rather than an 8mm allen key job.
Have you looked on youtube for how to do it? It'sa the video fount of all wisdom mechanical.
Ah gotcha. In that case the suggestion above to position the crank arm and crank puller so that you can squeeze the two together is a good one, although personally I've never had a crank bolt that tight before.
Thanks. I'll try that.
I did watch a couple of Youtube videos, but they make it look easy (one of the demonstrators said he'd loosened the bolts before he started filming...)
Is it the crank bolts/nuts that you can't undo? You don't need a crank puller for those. You need to get them off before using any special tools - just a socket or spanner.
had to resort to a length of wood under the chain stays to stop the
crank arm from moving whilst "leaning" on the breaker bar - those
bolts can get quite stubborn !!!
Also - top tip - either put chain on outer ring or wrap chainring in cloth. When the bolts, or tanks, start to shift, knuckles can get a bit messy 🙂
Once the bolt is off, as above use mechanical advantage to get the crank puller and the spanner to move towards each other - so start at 25 degrees apart and squeeze..
Thanks. I managed to remove the crank this morning. The tip about using the other crank as a lever was helpful. I held a rag over the end of the spanner (to give a bit of cushioning to my hand) and then put a bit of effort in. I'm feeling strangely pleased now!
After installing new chain-rings I'll have to refit the crank, which could be another problem...
I'm almost tempted to see what's involved in removing the bottom bracket...