Crank puller middle bolt too big? Or wrong type of puller? (pic inside!)

cammey

Hello,
Just received a new crankset im about to install and ran into a problem with the crank puller. The outer large bolt lets the cank puller fit on the crankset perfectly, but the inner bolt is a few millimetres bigger than the screw in on the crank. The size difference looks like it will just destroy the threads on the crankset if i force it?

Any help appreciated!

sandyballs

Looks like every crank puller I have used. The inner bolt should be bigger it does not screw in or go into the BB shaft thread. The threads on the shaft are usually set below the surface so they should be protected. Just make sure the inner bolt is fully unwound so the outer can be screwed in fully before tightening the inner bolt.

k-dog

I had to use an adaptor once but that's because it was smaller, not bigger than the whole in the middle. That looks like it will work.

cammey

Sandyballs wrote:

Looks like every crank puller I have used. The inner bolt should be bigger it does not screw in or go into the BB shaft thread. The threads on the shaft are usually set below the surface so they should be protected. Just make sure the inner bolt is fully unwound so the outer can be screwed in fully before tightening the inner bolt.

Ah i see, i did try it and it seemed like it wouldnt go any further and i was scared it was going to mess up the threads on the inner shaft! Will give it a go tomorrow and just push past the point it seemed was resisting
Thanks!

cammey

k-dog wrote:

I had to use an adaptor once but that's because it was smaller, not bigger than the whole in the middle. That looks like it will work.

Thank's after you guys think it should work, i'll give it a go again tomorrow with some elbow grease !

bbrap

Wind the central bolt all the way back, pop a small metal disc (blanking plate) in, screw the extractor all the way in, then use the extrator as normal.

philclubman

Don't force it or you'll just strip the threads.

Does the silvery dome/knob on the end of the tool pull off?

I have a similar tool from when I had square taper BB's and the dome on the end of the tool was magnetic and came off to mean that it fit through the crank and pushed against the spindle of the BB.

cammey

bbrap wrote:

Wind the central bolt all the way back, pop a small metal disc (blanking plate) in, screw the extractor all the way in, then use the extrator as normal.

Oh mine doesnt have a small plate i can pop, its just how it looks on the pic, nothing else comes off. Do i need one with a special plate?

cammey

PhilClubman wrote:

Don't force it or you'll just strip the threads.

Does the silvery dome/knob on the end of the tool pull off?

I have a similar tool from when I had square taper BB's and the dome on the end of the tool was magnetic and came off to mean that it fit through the crank and pushed against the spindle of the BB.

The silvery dome doesn't pull off, its solid and a little down it turns into thread, basically identical to the pic below



Will this kind not work?

Thanks!

bbrap

cammey wrote:

bbrap wrote:

Wind the central bolt all the way back, pop a small metal disc (blanking plate) in, screw the extractor all the way in, then use the extrator as normal.

Oh mine doesnt have a small plate i can pop, its just how it looks on the pic, nothing else comes off. Do i need one with a special plate?

You can get blanking plates (I made mine on a lathe), but if you do not have one here is another solution. Put a grub screw with the same thread In the hole and tighten the extractor pin against that. If you do not have a suitable grub screw a small piece of threaded bar or offcut of a bolt will work just as well. All you are trying to do is give the extractor pin something to push against that will not damage the threaded hole.. Hope that makes sense.

veronese68

I've never bothered with a blanking plate, the diameter of the end of the tool should be smaller than the square hole, but larger than the threaded hole. It pushes against the end of the spindle drawing the crank off. If you are worried about the size wind the outer all the way back so you can check the size of the inner against the square hole in the crank. Then, as others have said, wind the inner all the way back. Screw the outer into the crank as far as you can by hand, no need to force it on with mole grips or anything. It should go quite a long way to get a good grip on plenty of threads. Then wind the inner in so it pushes against the spindle. You will have to use a reasonable amount of force as it is held on by the taper.
Once you've seen how it comes apart it will all make perfect sense.

k-dog

And it's incredibly satisfying! Haven't done one in years since I had to do one of my kids bikes last week.

cammey

Managed to get it off! Yay! Thanks for al lthe help folks!

Have a good weekend