Need to replace my left side crank arm

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Nomadski
Posts: 6
Joined: Mon Oct 29, 2012 17:20 pm

Need to replace my left side crank arm

Postby Nomadski » Mon Nov 05, 2012 17:32 pm

I have a Cannondale Synapse Alloy 5 105 (http://www.paulscycles.co.uk/products.p ... b65s6p4332) and today while riding I noticed my left side pedal moving laterally. Being 2 miles away from the nearest place I knew had a spanner I rode there and inevitably did more damage than good to the threading.

The pedal was at an angle so I knew it had somehow de threaded the inside of the crank arm, it fell off completely half a mile from there.

The guy managed to get it back on but said not to ride it again till it was replaced. He also noted my pedals were crap...Cheers mate.

Anyways, I need to find a replacement crank arm for the nondrive side, probably some new pedals too. Apparently its a FSA Gossamer, BB30, 50/34 crankset, but I have no idea of length of crank, or where I measure it from/to.

1. EDIT: Found out, its a 175mm crank arm.

2. Where can I buy just a crank (google is giving me nothing but cranksets)

3. Any ideas what has caused this? Its done about 200 miles in 3 months with no sign of trouble until this afternoon.

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Salsa
Posts: 727
Joined: Fri Aug 03, 2007 20:17 pm

Re: Need to replace my left side crank arm

Postby Salsa » Mon Nov 05, 2012 18:27 pm

If you installed the pedals then you must have cross threaded it, if Pauls fitted it then contact them for a replacement.
Windwave are the UK distro for FSA but they don't list left arms as a spare part, worth calling them though to see if your local lbs can order it from them. I've had to order a crown race that wasn't listed as a spare so you may get lucky. Otherwise I would go to an LBS with the facility to heli coil your arm, this will replace the thread and allow it to be re-used.
http://www.windwave.co.uk/contactus.html

Nomadski
Posts: 6
Joined: Mon Oct 29, 2012 17:20 pm

Re: Need to replace my left side crank arm

Postby Nomadski » Mon Nov 05, 2012 19:14 pm

Salsa wrote:If you installed the pedals then you must have cross threaded it, if Pauls fitted it then contact them for a replacement.
Windwave are the UK distro for FSA but they don't list left arms as a spare part, worth calling them though to see if your local lbs can order it from them. I've had to order a crown race that wasn't listed as a spare so you may get lucky. Otherwise I would go to an LBS with the facility to heli coil your arm, this will replace the thread and allow it to be re-used.
http://www.windwave.co.uk/contactus.html


It was me who installed the pedals, not sure how I cross threaded it, it seemed perfectly fine for the last 3 months, didnt seem to be an odd angle.

Does rethreading ever work? Always thought it was a bit temporary to do that.

Been looking around for the arm, the few places that sell it dont have it in stock with no ETA for it coming in. Really dont want to have to buy a whole new crankset for a for the sake of a crank arm..

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Monty Dog
Posts: 20382
Joined: Thu Dec 14, 2006 14:31 pm

Re: Need to replace my left side crank arm

Postby Monty Dog » Mon Nov 05, 2012 20:02 pm

You may be able to get a helicoil inset fitted to repair the crank - try your LBS or Highpath Engineering - should cost no more that £15.
Make mine an Italian, with Campagnolo on the side..

keef66
Posts: 8712
Joined: Tue Apr 29, 2008 09:46 am

Re: Need to replace my left side crank arm

Postby keef66 » Tue Nov 06, 2012 10:04 am

Just to reassure you, Helicoil is a permanent repair, probably stronger than the alloy thread it replaces. Frequently used in the motor trade to repair threads in alloy engine blocks / heads, so plenty strong enough for a pedal.


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