So being an idiot assumming that all square tapers are the same, I tried to take the Truvativ Isoflow crank off my bike. I uncrewed the lock bolt, inserted the crank-extractor and started to turn. Well it didn't bulge so I pushed a bit too hard and stripped the threads. I did some reading and realized that Truvativ crank came with a self-extractor nut inside and it seems to requires a big square bit to fit in. So now that the threads are stripped, is there anyway for me to get the crank out and what tool do I need for that self-extracting nut?

Uh Oh... the only thing I can think of is trying some sort of gear puller, but getting enough purchase on the crank could be a problem. About the self-extracting bolt, the top cap is usually threaded as well and it screws into the crank, so that undoing the bolt with allen head brings the crank with it. So if it was a self-extracting bolt, I don't get how you removed it while leaving the crank on the bb spindle? They usually look somethjing like this:


Just thought, with the right tap, you could maybe re-tap the crank - probably not a very helpful, or likely solution though...

[EDIT] Not sure if your crank is powerspline or square taper, but if it is the latter, could the square bit you mention be the taper in the crank that fits onto the bb spindle? I don't mean to be patronising, so sorry if that's not what you meant.

Gear pullers work, although, like RookieRoadie said, they can be a little tough to get the jaws to hold on. But it can be done - I, for one, have done it. It might be possible to rig something up with a hose clamp or large zip-ties to hold the jaws in while pulling... the outward force of the jaws trying to slip will be very small compared to the pulling force generated.

Also, you need to have something for the puller to pull against. In the past I have just used a crank bolt threaded in only far enough that I thought there were enough threads engaged to be sufficiently strong, but with the head still proud of the crank.

My crank doesn't have that type of self-extracting bolt. On my cranks, they are separate items and in no way connect to each other. I've never seen that type of design before.

Funny thing is that's the only type I've ever seen What sort are they, out of interest? In the ones I linked to, the black bit that screws into the crank is in fact separate from the bolt, like this:

To remove the black bit, you'd need a pin spanner or something. I don't know if there are any special tools other than that. But your crank is square taper, correct?

I believe FBinNY can direct you to some wedges that he recommends for removing cranks in such an instance.
https://www.bikeforums.net/private.php?do=newpm&u=158672

Hammer and a piece of wood. Smack the heck out of the wood against the cranks, obviously from the inside ok??. That will lose the cranks

The system has been in the market since probably 30 years and the 1st ones I saw with that was shimano 600 back like in 82. The funny thing if this makes the OP feel better... you are not the 1st one that does this and you wont be the last one for sure. Anyhow...why people don't think before doing...??? jezz...!!! You did the hardest part, to take the little cups out

The bolt has its own cover/cap attached to it and the black bit (extractor) is a separate piece that goes inside the crank. According to the spec, it is a square taper and from what I've seen it appears so.

Thanks. I read what I can find on the internet and watched youtube video before working on the crank. My ignorance on different types of bolts/nuts/extractors for square taper BB was my own fault. Previously I had only worked with the external BB.

Well, gotta try it at some point; everyone makes their fair share of cockups when wrenching on their bike, comes with it. Anyway, looks like using a wedge as per cny-bikeman's suggestion might be the simplest solution - good luck getting the crank off!

Thanks for the intro, but please don't PM me, about these.

Here's a link to Jacobs Chuck removal wedges that will remove those cranks easily and with zero damage. They're cheap and work so well that you might as well continue using the cranks as if they were undamaged.

I see you are NOVA... if you still have problems let me know to help you out. In which city are you?

This is how you fix the crank...

https://thegoldenwrench.blogspot.com/...xtraction.html

Nice tools, but kinda pricy for a home mechanic. A pair of wedges is usually less than $10.00

wood and a hammer is probably free.