How to remove a crank arm with stripped threads? A friend called me up yesterday after a mis-adventure during his attempt at a bottom bracket overhaul. He stripped out the threads on the (left) crank arm while using a Park crank puller. In a pinch, we rented an automotive gear puller but could not get enough purchase for that to work. 

Any tips on this? Especially a way that will not ruin the crank arm. (I know, the crank arm is now ruined in terms of future removal, but in the meantime with a bottom bracket overhaul and without any further damage, it'll get him through another season's commute.)



Update 12/31/2011 This question was asked over a year ago now, so problem solved at that time. Followed the advice by whatsisname and we got the crank arm to loosen by slowly riding around the block a few times. Once it was loose, we were able to finish the job using some strategic tapping with a padded dead blow hammer. Then replaced/rebuilt the entire crankset and bottom bracket. (The thing was trashed beyond the removal issues...) The recent additional answers may be of use to others who find themselves in a similar predicament.
Your crank arm is trashed. 

With the crank bolt removed, gently ride around a few miles, it should work itself loose enough that you can yank it off.

Otherwise many shops have basically a slightly larger crank puller for addressing this issue, where they chase out a larger set of threads, then use the larger puller to get it off. The crank arm typically goes into the garbage at that point however.