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[Closed] Stripped Middleburn Crank Threads

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[#7271745]

Last night the driveside crank's pedal thread stripped out on my friend's bike in the middle of a ride. S* happens, but they're nice cranks and we'd like to rescue the crank if it's possible.

Helicoiling is one option that springs to mind but is this a viable long term solution? it needs to be as straight as possible too which I imagine would only make the job more challenging than say 'coiling threads on a stem.

If it's of any help these are made of 7075. Some places say they'll only helicoil softer 6-series cranks. I'm not sure why. Does anyone know of a good bike shop or competent mechanic that can repair it?

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Posted : 17/08/2015 4:12 pm
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Hi,

I would personally organize steel sleeve with proper pedal thread and set it into the crank arm by pressing and/or liquid metal gluing.

Cheers!
I.


 
Posted : 17/08/2015 4:18 pm
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Helicoil would be fine. That said those cranks must be getting a bit old now, might be time to think about retiring them or moving them to a pub bike. Seen a few fail


 
Posted : 17/08/2015 4:23 pm
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That "nice crank" looks like it has been used as a hammer ? Is it worth an expensive repair


 
Posted : 17/08/2015 4:24 pm
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They used to live on a trials bike, now on my friend's 26" SSer.

Rescuing them would be the cheaper option than say getting a Zee crankset which is plan B if repairing the thread goes pear-shaped.

Who can get it done well?


 
Posted : 17/08/2015 4:40 pm
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I've had some luck in the past threading in a tap from the other side - Can't tell from that pic how much meat is left.

May be worth a try first?


 
Posted : 17/08/2015 4:43 pm
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Are middleburn small enough to send it back to for a repair.


 
Posted : 17/08/2015 5:29 pm
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Helicoil would sort that.

You could machine it out n plug it with an insert but I'd try a Helicoil first


 
Posted : 17/08/2015 6:29 pm
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highpath will be the people to speak to.

http://highpath.co.uk/


 
Posted : 17/08/2015 6:34 pm
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I have some nice shiny proper nearly new ones FS


 
Posted : 17/08/2015 6:42 pm
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Fully recommend Highpath, done a lot of excellent work for me in the past.


 
Posted : 17/08/2015 6:42 pm