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Discussion Starter · #1 ·
Now I did it. Was reassembling Dura Ace 10 speed crank arm, non drive side. Using torque wrench, at about 10 nm torque, Shimano instructions say 12-15 nm. Bolt head twists off. Able to get arm off, now what ?

Doug
 

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I've broken this very bolt before and at equally low torque. The good news is that once the head is broken off, it probably won't be very tight in the arm. I drilled it with my Dremel tool and then extracted it with a very small ezout. Wasn't near as bad as I thought it would be.
 

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TheHeadlessThompsonGunner
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If you've got small bits for a Dremel tool, you can slot the end of the bolt and run it through with a flat-head screwdriver.
 

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Discussion Starter · #8 ·
My attempt to remove bolt didn't work, FINALLY off to LBS

Applesauce said:
If you've got small bits for a Dremel tool, you can slot the end of the bolt and run it through with a flat-head screwdriver.
I don't know how that would work, the end of the bolt is down in the crank. I couldn't get a lead hole for the EZ out drilled in the center of the bolt, when it twisted off, left a point in the center. My hole then broke through the edge of what was left of the bolt, so the EZ out wouldn't take hold. LBS has retired machinist, who has machine shop at home, he thinks he can get it out and save me $175 it would cost for new DA 10 speed crank arm. I hope he is right.

This just went from bad, to worse, to worse yet for me. I just wasn't destined to resolve it, I guess :( I have a R700 compact on now, doing a hilly 110 mile ride in 2 weeks, and a week in Colorado, including Copper Triangle in about a month, wanted to try compact anyway. May put the DA crank back on later (once fixed or new arm), may not, don't know right now.

Doug
 

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TheHeadlessThompsonGunner
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DBtheCyclist said:
I don't know how that would work, the end of the bolt is down in the crank.
That's the "small bits" part. I'm not talking about a cut-off wheel. I'm talking about long, thin, pointy diamond bits. Take it slow - slower than you did with the EZ-out - and scribe a line - ONE line - back and forth. When it's deep - DEEP - put a narrow screwdriver to it.
 

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Discussion Starter · #11 ·
EZ out extractor bit is a left hand thread

cody1 said:
Its to late now to help, but in case this happens to someone else try a left hand drill bit next time. Most of the time they will loosen the bolt as you drill,not tighten it more.
However it won't start a hole on it's own, you need to drill a lead hold first, the bit (that came with the extraction bit) is a standard threaded bit.

Doug
 

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RoadBikeRider
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If it makes you feel better I will tell you what I did to my non drive side arm. Kept having BB noise, kept removing crank and BB. During the 4th or 5th re install I rounded out the head of the fixing bolt...no big deal. Went to 2 shops looking for a replacement. The mechanic at the second shop handed me a couple of bolts, shorter than the original. I asked him if they were long enough (he is the mechanic) and he said "sure". I took them home and proceeded to torque them down and stripped out the threads of the crankarm itself. I have always used a torque wrench for this area and the reason that it stripped is that the bolts were too short to get a good hold of the threads. My fix was to buy even longer bolts at the local hardware store (should have done this to start) and they are much longer than even the original bolts. They grabbed plenty of good threads, let me torque it down nice and tight but do protrude slightly out the other side...no big deal and I will cut them down next time I remove them. Do they sell individual non drive side arms? It is a R700 Compact. Does anybody know if any "Level" of Hollowtech would fit? I found a good deal on ebay but it is a Dura Ace. (just in case)
 

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Discussion Starter · #13 ·
I am using a R700 now, however..........

andulong said:
If it makes you feel better I will tell you what I did to my non drive side arm. Kept having BB noise, kept removing crank and BB. During the 4th or 5th re install I rounded out the head of the fixing bolt...no big deal. Went to 2 shops looking for a replacement. The mechanic at the second shop handed me a couple of bolts, shorter than the original. I asked him if they were long enough (he is the mechanic) and he said "sure". I took them home and proceeded to torque them down and stripped out the threads of the crankarm itself. I have always used a torque wrench for this area and the reason that it stripped is that the bolts were too short to get a good hold of the threads. My fix was to buy even longer bolts at the local hardware store (should have done this to start) and they are much longer than even the original bolts. They grabbed plenty of good threads, let me torque it down nice and tight but do protrude slightly out the other side...no big deal and I will cut them down next time I remove them. Do they sell individual non drive side arms? It is a R700 Compact. Does anybody know if any "Level" of Hollowtech would fit? I found a good deal on ebay but it is a Dura Ace. (just in case)
The Dura-Ace crank is much more sleek and elegant looking than the R700, which I am using now. I bought it a while back, to use on a hilly 110 mile ride in a couple weeks, and for a week in Colorado. I do hope that the LBS can get the bolt out, I may go back to it, though I may not. Rode 115 miles today, with the compact, though not really hilly, at least nothing major (I live in Kansas, we have lots of rollers, and some steeper 10-15% hills, but nothing that I would call an extended climb, so I didn't spend much time in the small chainring, which is the real reason I wanted to try a compact, to get the lower low gears. If I like it I might get something else, maybe carbon, maybe the new 7900 Dura-Ace compact, though early prices I have seen is $750 msrp (Shimano is really, really proud of this new DA stuff). Easton has a nice looking carbon crank coming out in the fall, though I don't know that I would want to drop the coins on it until I heard if there were any problems with it.

I don't really know the answer to your question, though. You sound like you devised a solution, why do you want a new arm, just to be on the safe side ? I don't really think it matters much to you, however on the Dura-Ace, the bolts cannot protrude through the crank arm, the holes don't go all the way through the arm. Unless you pull out the rest of the threads, I wouldn't think you would have any further problems, however I feel your pain, for sure. If they can't get the bolt out, or damage the crank arm in trying, msrp is $175 for a DA 10 speed crank arm. I did look on ebay, nothing at the moment, though since I am good with the compact, at least for now, maybe forever, I don't need to be in a hurry to replace it (if LBS can't take care of the problem).

Doug
 
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