I have rounded the 8mm drive-side self-extracting bolt.
*hangs head in shame*
I cannot shift the outer 2-pin washer with a pin spanner either.
Please, any helpful suggestions before I resort to backing off the non-drive-side adjusting ring and sawing through the axle?
You could trying cutting a channel across the head of the bolt to allow you to undo it with a large flat head screwdriver, a dremel is good for this. You can also buy screw/bolt extractors where you drill a small guide hole into the head and then screw the device into the head, it has a reverse thread so as you screw it in the bolt/screw is unscrewed. Or you can hit it with a mallet, won't work but you'll feel better.
Thanks. I think a bolt extractor is the way to go. I don't think a screwdriver will do it since a large p-handled 8mm allen key didn't do the job.
Some self extractors had a left hand thread, not sure if yours is though. Not had a huge amount of success with extractors on actual crank bolts(though it may work on the extractor cap if it's a right hand thread)as they're usually well tight, but mig-welding an old key in works wonders.
Ha! I think welding is a bit beyond my scope. I'm fairly certain the bolt has a right-hand thread so a bolt extractor might work. If not, it's time to get the saw out and start shopping for new cranks.
Aaaaaaaarrrrgh.
Sorry. I feel better now.
Most small garages will have mig welder if that's the way you need to go, will take a matter of seconds to weld if it's all set up, so may only cost a couple of quid. Much cheaper than a new crank.
You could try hammering in a trox socket and use a bit of heat on it?
Thanks for all your suggestions.
I didn't consider a torx socket. My local tool shop supplies them in individual sizes. Seeing as I rounded the 8mm bolt (and the allen key was undamaged) maybe a 9mm torx is the way to go?
So, I have a plan of attack:
1. Try hammering a torx socket into the rounded bolt and give it some welly with the socket spanner
2. Break out the drill and get a bolt extractor on the go
3. Find a friendly welder to mig weld an allen key to the bolt
4. Break out the saw (and the credit card).
The thing is, I'm diligent about greasing bolts. I suppose the logical answer is I overtightened it in the first place. Hmmm, you live and learn.
Just to update...
1. FAIL
2. FAIL
3. Not attempted due to having drilled out the bolt head during 2.
4. Ouch. The axle was made of cheese. Didn't take long.
Now, what chainset next...?
It's worth checking that the driveside crankbolt/extractor ring were assembled correctly in the first place. Mine happend to be missing the little copper/bronze washer that lets the bolt turn against the cap.
ummmm.... bike shops
Personally, I'd contact Middleburn and explain the situation.
The cranks come with a lifetime warranty and are modular. i can see no reason why the axel cant be replaced. Shame to replace some fine cranks.
I have the same cranks and have just checked mine are ok.
I tried to contact Middleburn via email a few weeks ago requesting some related info. No response.
Thanks for the suggestion about the missing self-extracting bolt washer - that sounds like it could be the culprit.
Alas, I think the only way to check would be to saw through the crank itself around the area where the bolt sits. I've basically written off the cranks anyway. I had to saw the axle in 2 places so I could remove the spider for future use. I'm fairly sure I've voided the warranty somehow...
I did recently discover some fitting instructions with correct torque values on the Middleburn website (though I received no such instructions with the cranks when I bought them).