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Help! I've ruined my Dura-ace cranks(6 posts)

Help! I've ruined my Dura-ace cranksSkid
Oct 4, 2001 6:16 PM
I was installing my Dura-ace cranks but i couldn't make it completely flush with the bb splines. i let it be anyway and i already rode it for 40 miles. then i decided i should try removing the cranks and putting more grease (i put almost nothing when i installed it, thinking that the existing grease from factory is sufficient). anyway it's really realy tight and i could see the threaded cap (one-key extracting crank system) bulge out against the pressure of the crankbolt but the crank is not sliding out. i thought i'm going to ruin the cap but i proceeded to force it anyway thinking that it would be OK as long as i remove the crank in the process. unfortunately i just succeeded in ruining the cap and the crank threads, but the crank is still tight with the bb spindle. this is only on the right crank; i was able to remove the left one.

Question: is there still a way i can remove the right crank even with the ruined threads on the cranks? would my lbs be able to do this? advice please. if there's no help i'll just ride the bike with the crank as it is.
re: Help! I've ruined my Dura-ace cranksKruser
Oct 4, 2001 8:07 PM
Skid - I too love to work on my bikes but one must know his limits (whether it be tools or skills). My advice is to bring into your local, trusty bike shop that has a good mechanic. This stuff is too expensive to ruin/damage. Don't keep riding on it.
Of course...TJeanloz
Oct 5, 2001 9:08 AM
You have to realize that you have irrecoverably damaged the right crank and bottom bracket. Once you've written them off, removal is easy. You have two options:

1. Try to get a crank puller in there and pull the crank the old-fashioned way. From what you've described, I don't think this will work. #2 is more fun anyway.

2. Use a bigger hammer. The crank is just being held on the spindle by friction. And you're not going to let a little friction-fit stand in your way. Be careful- it helps to have a friend around to hold the bike in position. Pound the spindle arms one-by-one and hopefully get it sliding. If you can't get it to fly off, use a bigger hammer.

3. Last resort- you could spend all afternoon doing it, but I don't see why you couldn't carefully slip a hacksaw in and cut the BB spindle off. It's painful to do this to new equipment- but remember, it's already trashed.

If you lack either the skills or the tools, any competant bike shop should be able to do this, heck even incompetant mechanics are pretty good with hammers.
Oct 7, 2001 3:45 PM
It occurred to me on my ride today that you could also back out the right side BB cup, and take along with it the BB spindle and crank. This might be cleaner, but I think the hammer approach would be more fun.
Much better idea.grzy
Oct 11, 2001 8:52 AM
Yeah, large hammers and cold chisels don't have much place on a good bike. It's hard to confine the destruction to just one or two componenets. Backing out the RHS cup may be possible with the special spanner made for DA/XTR BBs. At that point it will be a whole lot easier to determine what went wrong and what can be salvaged. The crank arm may or may not be toasted, but the BB could be perfectly fine and getting the two apart could be done carefully with a press.
re: Help! I've ruined my Dura-ace cranksPaul
Oct 11, 2001 8:23 AM
I believe you must have tightened the crank arms when they weren't meshed correctly, and ruined the threads. This is easy to do, but if you see the arm going on as you tighten, it's properly meshed ( should not see any part of the crank arm after tightening) correctly. If it is meshed correctly and you just cross threaded the dust cover, you could just put the cover back on and ride it for years. If you must remove it, best to bite the bullet and get a good mechanic to work on it. If you do try to get it off, use a plastic or rubber mallet, and tap it lightly observing that it's coming off evenly, if not, you can jam it so it never gets off.

I ruined a couple of threads on the previous model, but it still holds find, and forced the crank arm all the way onto the bottom bracket. The BB on your bike might be okay, you can always retap it once the crank arm is off.

Again, see a good mechanic.