Removing cranks from a square taper BB…

…once the threads in the cranks are stripped. 😳

Ideas please…?

Desructive (tocranks and your nuts!): undo or even remove bolts, ride around and pop off kerbs until crank loosens and falls off. You will trash the tapers on the cranks but possibly not the bb.

I have also heard folk using car bearing pullers but you would need a smallish one i guess.

oh also if crank is alloy (which square taper ones aren’t tbf) then its a 10 minte job to dremel a slot in the bit where it meets the bb spindle and then use a big flat screwdriver to prise it open a bit till it drops off. obviously also destroys the crank!

angle grinder/saw and cut through the crank arm.

a hub puller might do it if you can get one that’ll grip the arm.

or just ride the bike round for a bit without the bolt in place – it may free up.

Misrule of thumb:

Thanks – not worried about destroying the cranks as they are going in the bin.

wwaswas – Member
just ride the bike round for a bit without the bolt in place – it may free up.

i’d be amazed if this didn’t work.

(but you may be riding around with 1 crank for a few minutes)

Heat up the crank at the interface then come at it from the other side of the frame with cold chisel and mallet.

riding around should remove it. or you could use a mallet and try whacking it until it pops off the axle. might take you a while and beware flying crank arms

you could use a mallet and try whacking it until it pops off the axle.

I thought of this but was worried about what stresses such effort would put through the frame. Its a cheap frame I guess (Defy) which I am upgrading so I guess if it breaks I just divert to Planet/Ribble for new winter one.

Secure crank arm in a vice then **** the end of the axle with a big screwdriver/chisel and a mallet (make sure you have someone to hold the frame when it pops off).

ahwiles – Member

wwaswas – Member
just ride the bike round for a bit without the bolt in place – it may free up.

i’d be amazed if this didn’t work.

Be amazed. The LH crank may fall off, the RH one won’t.

hacksaw/chisel the easiest IME, hitting things with a big hammer when a light alu frame is connected is not the best idea IMO, and takes massive hits, if it even works at all.

As above, we always just rode a bike for a bit if they were stuck, particularly if you’re going to bin them anyway. A couple of kerb hops usually sorts it.

I have hacksawed through a crank arm before (blade only – too ages…) but that was a desperate case and properly corroded on.

linky

Ride it or use a cold chisel and a hammer against the back of the area of the crank around the BB axle.

^^ flywheel puller FTW

you could use a mallet and try whacking it until it pops off the axle.
I thought of this but was worried about what stresses such effort would put through the frame. Its a cheap frame I guess (Defy) which I am upgrading so I guess if it breaks I just divert to Planet/Ribble for new winter one.

i did this many many years ago. i didnt have a crank puller tool and couldnt be bothered to take it into the shop to have it removed.
took me about 30 minutes of whacking it and cursing it but it finally flew off (literally). i rode the frame (alu) for another couple of years using the same cranks. had no problems so you should be fine so long as you’re careful

IIRC i used an old seatpost between the bottom bracket shell an the top of the crank so more of the impact force was near the axle itself

Angle grinder in line with one of the faces of the square taper will see you right and take about 5 minutes.

Ride it or use a cold chisel and a hammer against the back of the area of the crank around the BB axle.

Just spent 15 minutes hammering to no avail. Off to get the hairdryer…

You can get an angle gridner for about £20 – and you know you’ll use it again…

Oh and boiling water is a good way of getting heat on if you don’t want to use a blowtorch.

I’m at my wits end now.

I’ve heated with an hairdryer and hammered with chisel a lot – no movement either side. I’ve attacked the no drive side with a hacksaw which appears to want to take about 24hrs of sawing and bent the chainrings accidently with a swing of a mallet.

Now the bike is unsuable and an embarrassment to take to the LBS.

Help!

It has taken me an hour and a half of battering in a bike shop before. It will take a long time.

I’d jump up from hair dryer to kettle. Failing that then it’s angle grinder time but it should be noted that working in shops only once did we ever have to resort to this and it was on a crank that’d been on the axle for 25 years and the bike spent most of its life left outside. Heck even last night I got four cotter pins that’d been on a bike for around 50 years with an hour and a half, a hammer and some patience.

When you use an angle grinder it’s as much the amount of heat as the cutting that shifts it so have a couple of whacks with the hammer in the breaks between cutting.

Choices are:

Suck up embarrassment and go to LBS

Buy cheap angle grinder

Drive over to mine and I’ll angle grind it off for you and attempt to embarrass you further

Edit : or one of those pullers pictured above – bit less brutal

Am I doing this right? 2 kettles of hot water and the crank is too hot to touch yet nothing:

image

Of course I am rotating the crank and hitting it in different places

If you don’t fancy the angle grinder, you can just drill a series of holes into the crank and then ride it a bit.

I dont have the tools.

At the point, the whole frame is going in the bin TBH

🙂

Chill

…and take it to your LBS.

[i]Steven Berkoff[/i] There is no shame…[/Steven Berkoff]

That’s essentially right, though your chisel is a touch weeny for the job. We used to have something which looked like a chisel but much bigger that we called a battering tool and I thought was called a battock but I can’t for the life of me find what it’s really called.

Are you using a lump hammer? If not do.

As for the LBS, they will do essentially what you’re doing before angle grinding it if it really is so bad. For the cost I would buy an angle grinder yourself.

Next time grease the shit out of your extraction tool and really push it home.

Just go with the angle grinder option now Kryton,you look like an angle grinder kinda guy.

If by some minor miracle you buy,borrow or steal a puller,don’t forget to put a jubilee clip round the legs. 🙂

Surely someone could lend you a drill? Or just buy a hand drill from somewhere cheap – it’ll do the job for what you want.

ok look, homebase is a mile up the road.

The angle grinder option – where/what do I grind? The out surface down the the BB taper on the non drive side for sure, but what about the drive side? I won’t get it between the rings and the BB shell…?

Take the rings off first.

You should be able to remove your rings in situ.

Edit : Gah, beaten

Teasel ,he should just bring it round to yours. 😉

To be fair, we’re I’m not that close…

😉

Ok rings are off. Just cut off a spider are and then grind down to flat?

What Angle Grinder to remove cranks ? 😀 😉

Ah well,the grinder will bring out the bodger sculptor artist in him 🙂

I can’t believe you hadn’t already taken the rings off while attacking it with a hammer/chisel/etc 😆

What did I tell you?

Get the proper tool (like Shand’s link, or the Stein tap & tool, which some LBS have) or an angle grinder.

Hammer/chisel is an awful thing to put to a bike. Taken much pain of the bb shell yet?