Need to replace my left side crank arm

[Nomadski]

I have a Cannondale Synapse Alloy 5 105 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 pedal from the inside of the crank arm, the pedal 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.So how do I find out length of the crank (which points do I measure?)
EDIT: Found this out, its 175mm.

2. Where can I buy just a crank arm (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.

 

[Cycleops]

Looks like you might just have to bite the bullet on this one, although it may be possible to buy a pair of cranks without the rings if you shop around. Don't forget you will need to buy a crank extractor if you intend doing it yourself. As to what might have caused it, that is a mystery. Pedal could have worked lose as it might never have properly fitted in the first place. You could alternatively try to obtain a second hand set. Sorry but I don't think there's any short cut, unless anyone can suggest one.

Your post seems to suggest you had the bike from new so you might have a case against the retailer who sold it to you.

 

[mrandmrspoves]

If you want to replace like for like a specific search on eBay may turn up the exact part you want http://www.ebay.co.uk/itm/FSA-GOSSA...sure_cycling_bikeparts_SR&hash=item3ccc2c5fa2

If you want cheap functionality type in 175mm crank and you will find lots of similar but not necessarily matching crank arms - just choose one that looks the same - and has the same fitting.

The most likely cause of your problem was incorrect initial fitting of the pedals....Right Clockwise - Left Anti-clockwise. This is counter intuitive as we tend to think clockwise to tighten... and consequently there are an awful lot of ruined left cranks!

 

[Nomadski]

Its weird because I followed a bunch of youtube videos showing how to put pedals on, and there wasn't any bite, it went all the way on straight. Its done a couple of hundred miles before today, so I just don't understand whats happened.

Thanks for the link.

Had a look at my crank to get it off, and I havent got a clue. Theres a 10mm hex inside, and my hex key gives it a quarter turn but no more. There is what looks to be a collar with a bunch of tiny holes around it, am I supposed to be taking the collar off? Or does the collar come off with the bolt, just need more force?

Im guessing I need another special one use tool to get this done, this crank extractor Cycleops mentioned I googled but just looks like a fancy allan key?

EDIT: Ive also seen this on ebay - http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=221145553986. Would that FSA Vero RPM Left 175mm one be compatible? Right now dont care about looks, just want something to work for the next few weeks as I have some time off I wanted to spend some quality biking time.

 

[mrandmrspoves]

Sorry but I am not totally sure... I believe your crank has a self extractor which should come loose just by undoing the bolt. But I haven't ever worked on one. I am sure that someone more knowledgeable will be able to give you more reliable advice.....in the meantime have a look at the technical section of www.fullspeedahead.com which is the FSA info site

 

[Kestevan]

The LHS crank on the FSA BB30 crankset uses a self extractor. You should just be able to release it by undoing the 10mm hex bolt.

You might find it needs a bit of a tug to persuade it to release, but should then just unscrew.

 

[Nomadski]

Sorry but I am not totally sure... I believe your crank has a self extractor which should come loose just by undoing the bolt. But I haven't ever worked on one. I am sure that someone more knowledgeable will be able to give you more reliable advice.....in the meantime have a look at the technical section of www.fullspeedahead.com which is the FSA info site

Typically there is no info on my crankset on the FSA page, no tech support, no manual, no FAQ. Every distributor shows it out of stock, spoke with a few LBS who rang their own people and none due in till January! Doing my head in.

I wouldn't mind if this was pro stuff, but this is a pretty middle of the road crankset, it shouldn't be THIS hard to get spares. Being a 2012 model its almost like FSA have dumped it in the river and whistled while they walked away.

Am looking at maybe going another route, I have Shimano 105 gearing and derailleur, and my LBS sells the Shimano 105 5700 Double Chainset 50/34 crankset with 175mm arms which matches my current crankset bar the BB30 bit, which I understand I would need an adapter for.

1. Is that a good way to go in your guys opinion? Am I going to find less issues when I have problems with components?

2. Do I need to buy a new chain?

3. What BB30 adapter "name" am I looking for to ensure compatibility?

The LHS crank on the FSA BB30 crankset uses a self extractor. You should just be able to release it by undoing the 10mm hex bolt.

You might find it needs a bit of a tug to persuade it to release, but should then just unscrew.

Cheers for that, didn't want to give it more force than necessary if I had to take collar off somehow. Have done enough newb damage to my bike.

 

[Kestevan]

You might find this useful:

http://www.fullspeedahead.com/stora...139fdcde13fe_ZSP002-BB30_Road_Crankset_v0.pdf

 

[mrandmrspoves]

or this...... http://www.fullspeedahead.com/stora..._BB30_Crankset_English_20100118_v4_ Bryan.pdf

As it is only the left hand crank arm I would go with just replacing that if possible - cheaper (hopefully!) and easier.