# Force Crank Failure



## zoikz (Sep 5, 2003)

Metal piece where the pedal mounts is flopping all over the place. Guessing whatever they used to bond the metal to carbon gave out. 
Anyone else with this issue? It's out of warrantee so I guess I'll just have to eat it and get a new crank. Lame, lame, lame. Someone remind me why everything is made out of carbon these days.


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## jellis25 (Oct 6, 2009)

Are you referring to the metal washer that goes between the pedal and the crank arm?


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## skaruda_23 (May 8, 2009)

zoikz said:


> Metal piece where the pedal mounts is flopping all over the place. Guessing whatever they used to bond the metal to carbon gave out.
> Anyone else with this issue? It's out of warrantee so I guess I'll just have to eat it and get a new crank. Lame, lame, lame. Someone remind me why everything is made out of carbon these days.


Can we see a photo?


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## twiggy73 (Jan 19, 2010)

skaruda_23 said:


> Can we see a photo?



Yes a photo would be good did it squeak or anything like that to give you a clue it was getting worn ??? or did it just give way ?? 

Twiggy


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## asad137 (Jul 29, 2009)

Sounds like he's talking about the threaded insert bonded into the end of the crank arm for the pedal to thread into.

You could try finding the highest strength epoxy you can find and gluing it in place...but I doubt you'd be able to do the appropriate prep and get the right amount of glue in there.

Asad


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## zoikz (Sep 5, 2003)

asad137 said:


> Sounds like he's talking about the threaded insert bonded into the end of the crank arm for the pedal to thread into.
> 
> You could try finding the highest strength epoxy you can find and gluing it in place...but I doubt you'd be able to do the appropriate prep and get the right amount of glue in there.
> 
> Asad


bingo
that's the problem. nothing a photo would show. thought about trying to rebond it but technically I don't think it's feasible.
Just gave out suddenly, without provocation.


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## Boardmill (Oct 15, 2005)

You should be able to bond the piece in again. Centering it in all directions will be pretty important.

Normal epoxy is NOT likely to work well at all. This is unless the insert has some groves in it to resist spinning/ moving and is not relying on the bond. The strength of the epoxy is not very important as long as the epoxy is decent (do you really need 10,000 PSI compression strength?). What matters is the 'peel strength' of the bond to the metal. Most epoxies don't stick well to metal at all. 3m has really good products specifically for this. ScotchWeld will get it done and is pretty easy to come by.

To do it:
Tape the area up with some good packing tape (the $5 a roll 3m/ Scotch again "Super Strength Packing Tape' and then cut the hole out carefully with a razor blade. Mix up the material and put your part in. It would be nice if you could make sure the part stays centered, maybe a simple jig or clamp. Let that stuff dry to the directions. Sand off the excess without sanding through the tape. Call it done. 

Rough up the inside of the crank arm and the outside of the metal insert with between 120 and 220 paper first. Also key that you keep the threads from getting epoxy on them.

It will probably be better than new.


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## -dustin (Jan 11, 2009)

I'd go to your local shop with the cranks and have them contact SRAM. Nothing to lose, and SRAM's warranty tends to be pretty liberal.


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## twiggy73 (Jan 19, 2010)

was this a 2010 crank of a later year ?? 

Twiggy


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