# Re-Threading pedal threads on crank arm



## XC Jedi (Feb 8, 2004)

I stripped the threads on one of my crank arms where you screw in the pedal spindle. I have a tap and die set, and would like to re-cut the threads, but it doesn't look like there will be enough metal left on the arm for the threads. A friend told me that I need to drill the hole out and put in a metal ring or bushing, then thread it, but thats all he knows. Has anyone here done that? Could you give me some guidance? Thanks.


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## U V (Feb 29, 2004)

tap and die only realy works when theres some thread still there so if its all just striped off you've no chance.
as tap and die cuts a new thread, the hole is made slitely bigger so you might have trubble with the pedal staying on


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## angry-johnny (Mar 2, 2004)

*threaded insert or Heli-Coil*

I'm a tool & die maker and I've had excellent results with Heli-Coils. It may be an expensive fix though since you may have to buy a whole kit for just on repair. Have you looked into the cost of getting a new crank arm?
I also work part time at a bike shop and I've seen a crazy downhiller come in with a slick threaded insert he purchased at another bike shop. It was a steel threaded insert, you have to drill and tap the crank arm for the larger insert's threads & thread in the insert using lock-tite for extra safety. The your pedal just threads into that like normal. I have no idea where the other bike shop got the insert from though but I know they do exist so check around at the shops in your area

Hope this can help you out.


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## Loudpawlz (Jan 26, 2004)

*There is a shop tool for this*

Call your favorite shop and tell them what you need - they may be able to take care of you.

The tool taps a slighly oversized hole and cuts new threads. A heli-coil is then installed with locktight. The end result looks like what angry-johnny is describing and is usually a solid repair. Depending on the quality of the crank arm, it may be cheaper than a new one. Expect to pay the shop's hourly rate - It's about a .5 to .75 hour job + the part.

Most REI shops have this tool and at least one tech who will know how to use it.


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## DaFireMedic (Jan 13, 2004)

*I had a similar experience..*



Loudpawlz said:


> Call your favorite shop and tell them what you need - they may be able to take care of you.
> 
> The tool taps a slighly oversized hole and cuts new threads. A heli-coil is then installed with locktight. The end result looks like what angry-johnny is describing and is usually a solid repair. Depending on the quality of the crank arm, it may be cheaper than a new one. Expect to pay the shop's hourly rate - It's about a .5 to .75 hour job + the part.
> 
> Most REI shops have this tool and at least one tech who will know how to use it.


I took it to my LBS and they did it for like $20. Its just as you said, they drilled it out and installed a metal ring (I'm assuming a heli-coil). I'd like to have gotten the tool and done it myself, but with the cost, combined with the fact that I'll probably never need it again, it made more sense to let my LBS do it. I think it would make sense for you to take it in also.


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## damion (Jun 27, 2003)

*Someone explain this one to me.*

Why are you risking a catastrophic wreck to re-thread a crank? How hard are you on the bike that the crank is on? Body weight?


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## XC Jedi (Feb 8, 2004)

*Do you know of any problems from this?*



damion said:


> Why are you risking a catastrophic wreck to re-thread a crank? How hard are you on the bike that the crank is on? Body weight?


Cranks are expensive, and I don't want to buy a new set if I don't have to, but I certainly would if I thought I was risking injury. I weigh about 175 right now and ride cross country, no significant jumps, etc. I followed the advice of the other posters and my LBS did the work. I doubt there will be catastrophic failure from this repair, unless they did the work wrong. The mechanic said that this kind of repair is not uncommon. It feels pretty solid, but I'm no expert. Have you heard of failure from this type of repair before?


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