Bicycle Mechanics - Help, my crank is falling apart and i want to replace

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drewmk2
07-22-08, 10:57 AM
Hi all,

I currently have an 07 Cannondale Synapse 2 (click here (http://www.cannondale.com/bikes/07/cusa/road/synapse_alloy/model-7RAS2T.html) for more info).

Unfortunately the Truvativ triple crank started coming apart at 350 miles. I had it replaced under warranty.

Guess what? It's falling apart again. This time I want to replace it with an Ultegra double. I know i will have to change the front derailleur since it was a triple before. Do I need any other components? Will my bottom bracket be alright to use?

Thanks in advance.

drewmk2
07-22-08, 09:42 PM
Ok, so after further research i see that i will need cranks, new BB, new FD, and new BB cups?

It looks like the 105 shifters are compatible. Can someone confirm my beliefs?

Shall i just get an Ultegra triple instead, so i dont need a new FD?
stevetone
07-23-08, 06:53 AM
Just curious...how does a crank fall apart?

awc380
07-23-08, 08:52 AM
...hmmm.
Is this like an 'I want a better crank' falling apart?
Or is it disintegrating? Or did an arm snap?
drewmk2
07-23-08, 09:33 AM
Its loosening off the spindle, the same way it happened last time. It's def. a crank problem though. The inner threads were wearing off last time. Either way, I'm not going to be satisfied till it's gone :).
stevetone
07-23-08, 09:36 AM
Its loosening off the spindle, the same way it happened last time. It's def. a crank problem though.

Are the insides of the crank hole being rounded out, or is the crank bolt loosening up? Or both?

Edit: Or is it one of those new-fangled bottom brackets that I have no experience with (and should keep quiet)?