getting a stripped crank arm off

ives said:

Does anyone know of a way of getting a crank arm off the square taper of the bottom bracket if the dustcap threads have been stripped?

On this page there are two pullers (one for lefts and one for right arms) made by CalVan, specifically for stripped out crank arms:

http://www.biketoolsetc.com/index.cgi?id=924194847466&c=Tools&sc=Crank&tc=Extractors

You best bet is to call around and find a shop that has these tools, or something similar.

However ..... If you happen to have a cup&cone style BB and you can get the other side crank removed and you can get the BB cups removed from both sides, then you will end up with the stuck crank arm, the stuck axle, and one cup and bearings (dangling). Then you can brace the crank arm in a vise and drive out the axle with a big punch.

ives said:

Does anyone know of a way of getting a crank arm off the square taper of the bottom bracket if the dustcap threads have been stripped?

http://www.parktool.com/repair/readhowto.asp?id=136
is a rethreading tool that Park shows made byBicycle Research Company that may work.
or.....
Yes, a bike shop in your area likely has the tools and the know how. If you want to do-it-yourself you can find a bearing puller that has the correct dimensions to do the job. I suggest that if you D-I-Y, you use plenty of grease on the puller threads, but be careful not to get any lubricant on the jaws. The fit of the jaws is different on a variety of bearing pullers. You need to find one that mates well but has clearence.

I had this problem a few months ago with one of my bikes. If you want to keep the cranks then go with what the other posters said. If you're replacing the cranks and don't care what happens to them then I suggest cutting them off or pulling them off. If it's the non drive side you can get a crank puller from an auto store which has either two or three arms which fit around the crank with a large screw on bolt down the middle. Turn the bolt and the arms will lift and eventually pull the crank off (kind of like how a corkscrew works; sort of). If it's the drive side you will have to hacksaw your way through the crank arm. Aim to get the blade down one of the four sides of the BB spindle (not straight down the middle). Saw down beside the spindle. I managed to hacksaw about an inch down beside the spindle before getting a chsiel and rubber mallet. A couple of whacks and the crank split in half. Pulled it away and installed the new cranks. A little frustrating but it can be done. Good luck.

1id10t said:

I had this problem a few months ago with one of my bikes. If you want to keep the cranks then go with what the other posters said. If you're replacing the cranks and don't care what happens to them then I suggest cutting them off or pulling them off. If it's the non drive side you can get a crank puller from an auto store which has either two or three arms which fit around the crank with a large screw on bolt down the middle. Turn the bolt and the arms will lift and eventually pull the crank off (kind of like how a corkscrew works; sort of). If it's the drive side you will have to hacksaw your way through the crank arm. Aim to get the blade down one of the four sides of the BB spindle (not straight down the middle). Saw down beside the spindle. I managed to hacksaw about an inch down beside the spindle before getting a chsiel and rubber mallet. A couple of whacks and the crank split in half. Pulled it away and installed the new cranks. A little frustrating but it can be done. Good luck.

(manly way of getting things done)

thanks for the ideas.
I guess I'll take it into my LBS and see what they can do.

Cheers
Ives

Might be too late if you already brought the bike to the shop. But anyway sometimes if you just remove the crank bolt and ride (don't go too far from home obviously) the crank will work itself off quite quickly.

meehs said:

Might be too late if you already brought the bike to the shop. But anyway sometimes if you just remove the crank bolt and ride (don't go too far from home obviously) the crank will work itself off quite quickly.

Yes, this will definitely work, but .... The really important thing to mention is that as soon as you feel even the slightest loosening in the crank you need to cease pedalling. Otherwise, you run the risk of permenantly damaging the flats on the crank arm, thereby rendering it junk.