Uhm... How to remove a mangled, square taper crankset?

[Nooch]

Friend of mine asked me to do some work to his bike -- somehow he deformed the heck out of the non-driveside crank arm at the bolt, so I can't thread a crank puller into it. So, I started reading and saw that since it was toasted anyway, I could destroy it -- I'm trying not to hurt the bottom bracket, but so far I've been three cuts with the sawzall and it's still not budging -- thinking I might have to go deeper...

Of course this would be better with pictures -- I'll work on that... but anything else to try?

[David Kirk]

An automotive gear or steering wheels puller will often work.

dave

[Look585]

Can you remove the crank bolt? If so, ride it around the neighborhood without a crank bolt and it will fall off on its own in relatively short order.

[muz]

Is the bike in ready to ride shape? A short hilly ride with the bolt off could help.

[Nooch]

Originally Posted by muz

Is the bike in ready to ride shape? A short hilly ride with the bolt off could help.

I suppose i could put the drive side back on and the pedals and see what happens -- thanks guys!

[FlashUNC]

What others said, but I've done it with a bike on a trainer. Fair warning the BB might be toast as well.

[dddd]

Originally Posted by Look585

Can you remove the crank bolt? If so, ride it around the neighborhood without a crank bolt and it will fall off on its own in relatively short order.

There is a much quicker and safer way to loosen a tight arm, I do this occasionally so as not to break the tools.

What I do is loosen the bolt just a couple of turns, then position the bike next to some kind of railing, so I can support myself while aboard the stationary bike.
With one brake applied, I pedal backwards until the cranks are horizontal, then jump on the pedals a couple of times hard. Then I turn the cranks backward a half-turn and repeat.
Repeat this sequence a bunch of times, then re-check that the crank bolt is still free from any tension. Repeat until the arm loosens.

It helps greatly to apply a liquid penetrant to the spindle end first!

This method also can assist the bedding-in process so as to get the arms better seated, which is very important when using non-steel bolts, or when the spindle perhaps has 10mm threaded studs instead of fine-threaded 8mm bolts.

I more often do this with the fully-tensioned crank puller in place, to crack loose a stubborn arm. But it does also work in other situations such as this one.

[jc031699]

Long ago found this, I think on paceline. Used this on a crankset multiple times. It makes them usable again with the expectation of removal with this technique if you wish.

From McMaster Carr



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[unterhausen]

I like the idea of riding it with the bolt backed off.

People loosen a stuck wheel on a car by driving it with the lug nuts loose. The people that take the lug nuts all the way off regret the decision

I always wanted a gear puller, but never found a good reason to buy one. Which is weird, because usually I don't need a good reason to buy a tool. They should work though.

[cmbicycles]

Get a bigger hammer. Just kidding, sort of. Gear pullers may have a hard time grabbing onto the crankarm depending on shape. Do you have any hard wood wedges or a pickle fork (ball joint separator)? Heating the crankarm may also help as the steel and aluminum will expand at different rates. If you do ride around the neighborhood to loosen it, dont take the bolt all the way out, just loosen it... could come off at an inopportune time otherwise.

[Dead Man]

Originally Posted by unterhausen

I like the idea of riding it with the bolt backed off.

People loosen a stuck wheel on a car by driving it with the lug nuts loose. The people that take the lug nuts all the way off regret the decision

I always wanted a gear puller, but never found a good reason to buy one. Which is weird, because usually I don't need a good reason to buy a tool. They should work though.

many years ago when i was very young and very stupid (as opposed to my current middle-age and very stupid), i forgot to tighten down the nuts after i replaced the rear shoes on an old truck. i got about three blocks road-testing t he brakes before i watched my wheel go bouncing down the road as i ground my drum down flat

not a method id endorse... and im usually a let-fly! kinda guy

[chrismoustache]

I've dealt with a few cranksets that have had the crank puller threads too damaged to be useful. If I remember correctly, most more modern cranks use a 22mm thread. I tapped the threads to 23mm, which is the TA standard, then used a Park CCP-1 to pull the crank off.

[Nomadmax]

Die grinder on the left arm at the BB spindle.

[ddeand]

I just had the same problem with destroyed threads on the nds. I ended up using Kroil and heat and a pry bar. It eventually came off.

[cinema]

a little while ago a friend of mine had an aluminum crank arm stuck on a steel taper. he drinks sugar drinks constantly on the bike and they had been leaking for the better part of the decade. shop couldn't get it off nor could i with a pry bar and a torch. ended up just carefully chopping it off with a thin cut off wheel. ground the arm down inwards towards the shell so i could get clearance to chop the taper. not recommended as the aluminum can get hot but i wore some leathers and a facemask and went to work. the automotive pullers on hand wouldn't fit securely between the bb and crank arm but they probably would have after i ground the arm down, but at that point might as well finish the job.

the other ideas here might work if it's not oxidized and seized like this one was... but if it is, a grinder is quick.