This is totally my fault. I know it, but I still feel this in the pit of my stomach.
I have a nice (to me) set of XTR M980 cranks on my hardtail. I love them, they remind me of graftons of old, but are light and stiff and actually work and due to their pretty ow profile, haven't been scuffed to death (I have killed XT's with shoe rub).
Messing about with new winter shoes, and the combo of not enough side adjustment on the shoe and the low Q factor of the cranks mean that riding them is uncomfortable, even with 2 pedal shims either side. Not a problem, I'll have them as my 'summer cranks', cos that's a thing, yeah?
The bike has been left outside probably too much, not brought into the dry enough, the cranks haven't been off enough and I probably haven't re-greased the bolts for and age, oh, and winter. But now, the inner crank pinch bolt has rounded.
first thing to try, hammer in a larger torx. didn't grip.
large flat blade bit. didn't grip and took the shoulder off the bit.
Try both again, but will tighten the other bolt a bit more to release some of the pressure. nope, didn't work.
Then try to slacken the good bolt. guess what, that has rounded too!
Drilled a pilot hole for an easy out (3 drill bits later). easy out won't grip.
Then I remembered, it's XTR, so the bolts are Ti.
There's that pit of stomach feeling that I'm going to need to do something more drastic and possibly write off the crank arm.
Dremel cut off wheel on the outer seems to work OK. not quite all the way through as I don't want to catch the axle.
part way through the inner one, but I'm close to the BB, and there's not enough diameter on the wheel to go more than about 1/3 of the way. Larger diameter cut offs are either a bit thick, though shaving a mm off the inside of the pinch bit of the crank arm isn't too bad, I went through a couple, and it still doesn't cut deep enough without taking the BB cup out too.
I have glass fibre reinforced discs too, but they are doing nothing on a Ti bolt.
so, tonights options are get some decent metal drill bits and drill the heads off so I can at least get the arm off and deal with it of the bike, or failing that. cut through the crank arm to release the bolts.
drill bits first.....
horrible feeling though. haven't felt it since having to hacksaw a gorgeous, 1 month old pace RC-35 pro class stem as the bolts had completely seized and only has 3mm hex heads!
:-/
It's just an old crankset. You'll get over it.
It’s just an old crankset. You’ll get over it.
maybe. well, yes, I'll get over it, but it is IMO one of the nicer looking chainsets out there, without going all 5Dev etc.
maybe I shouldn't get attached to bits of metal. I often get caught staring at bikes.
Hope it helped you to get all that out OP.
It’s just an old crankset. You’ll get over it.
That's not what he needs to hear right now. Bloke is clearly traumatised.
I'd try drilling the bolts out from the bottom end.
Might just catch enough to unscrew them, oh and heating the crank arm might increase your chances.
Hope it helped you to get all that out OP.
thanks.
it did.
Scienceofficer is a buttmunch.
😉
They are the best looking HTII cranks Shimano hav ever made IMO so worth trying to save them. Plus having anything XTR is always nice
Before you try drilling titanium, it's worth looking for a video on machining titanium by This Old Tony on YouTube, it'll tell you all you need to know about not screwing it up irretrievably, before you screw it up irretrievably.
Decent drill bits and the bolt heads came off without much effort.
At least the crank is off now and replaced with my turbines. I can spend a bit more time with the crank arm to remove the dead bolts with minimal damage.