# Heli-coil for a clydes crank arm



## throwfar (Oct 10, 2009)

Ended up stripping my SLX driveside crank arm today. Pedal came loose and by the time I realized it, the damage had been done. 

I have seen discussion of a heli-coil to re-thread the crank arm but is is safe for a 270lb clyde? My LBS looked at me like I was crazy when I mentioned it but I'm not sure if this is because they want more $$$ or not.

Anyone attempt this before?


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## DSFA (Oct 22, 2007)

If it's done correctly a heli-coil should be stronger than the aluminum threads.

Sadly most LBS's are setup to be replacement centers not repair stuff anymore. And, fwiw, a lot of that has to do with the manufacturers not supplying replacement parts or supplying them at a reasonable cost.


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## One Pivot (Nov 20, 2009)

dont use a helicoil, its not sturdy enough. you need a threadsert kinda thing. its like a helicoil, but a solid insert, not just a spring. 

id be surprised if a machine shop couldnt do it for you. easy stuff, quick repair. ive used them for cars under lots of weight.. application was a little different, but i think id trust a threadsert.


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## savagemann (Jan 14, 2008)

Yea, you don't want a heli coil. You want the threaded insert like One Pivot mentioned.
I do these repairs all the time at work.
In fact, I just did one today.
The inserts are not cheap, and the taps are quite expensive.
I usually charge about $30 to do it.


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## throwfar (Oct 10, 2009)

So since bike shops usually don't do this should I be contacting a machine shop? Do I need to give them a pedal so they know what size to fit it or can they just use the other crankarm as a guide?


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## AZ (Apr 14, 2009)

throwfar said:


> So since bike shops usually don't do this should I be contacting a machine shop? Do I need to give them a pedal so they know what size to fit it or can they just use the other crankarm as a guide?


Take them the pedal also , that way there is no question .


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## savagemann (Jan 14, 2008)

I'd call a few shops, and explain to them that you stripped out the crank arm, and ask if they are setup to repair it with a threaded insert.
I'd be suprised if you can't find a shop to do this for you.


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## ImaKlyde (Sep 6, 2004)

Helicoil will work...is it the "best" option? No. Will it work? Yes. I've done it more times than I can remember and never had one come back. However, if you can...having a good machine shop do a thread-insert would be the best.

Brock...


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## mtnbiker72 (Jan 22, 2007)

A good bike shop will offer the service, it usually runs about $30-$40 including the helicoil insert. I've done a couple myself, it works fine.


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## 123ski (Jun 16, 2008)

if a shop tells you that they can heli-coil it and that they do it on downhill bikes all the time and that it is always strong and never has issues do you think they are doing standard helicoils or threaded inserts (just calling them the wrong name). Mine is getting done right now and i'm not sure what they are doing. I am not a clyds, I am 165lbs and this is on my 7" travel Freeride/AM bike.


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## murree21 (Nov 11, 2010)

I actually like the helicoils better than the threaded inserts, but either way if they are done properly they will be stronger than the aluminum threads.


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