Hi,

I recently bought a 2011 Specialized Allez off of craigslist. The bike is in great condition but the owner put on a really weird drive train on it. It comes with Shimano 105 ST-5601 shifters, which are meant for a 2x10 system, but he had a truvativ triple crankset combined with a 9 speed cassette on the back. I've decided to keep the shifters and put on a double crankset and a 10 speed cassette at the back. My question was regarding the combination I should go for and the ratios. I'm currently thinking of a 50-34 compact crankset up front, mostly because I'll be in California for a couple of months and the compact will be helpful with the hills. But I'm also moving to Dallas soon so I'm wondering if a standard double is the way to go.

Here are the parts I'm currently thinking of.

Shimano 105 5750 Crankset - wiggle.com | Shimano 105 5750 Hollowtech II Compact Chainset | Road Chainsets
Shimano 105 5700 Cassette - wiggle.com | Shimano 105 5700 10 Speed Cassette | Cassettes And Freewheels
Shimano Ultegra 6701 Chain - wiggle.com | Shimano Ultegra 6701 10 Speed Chain (116 Links) | Chains
Shimano BB-R60 Ultegra 6800/ 105 - 5800 Hollowtech ii BB - wiggle.com | Shimano BB-R60 Ultegra 6800/105 5800 Hollowtech ii | Bottom Brackets

Also I'm assuming that I need an English threaded BB but haven't confirmed this yet (gotta find the manual for the frame). On another, does the crank arm length make a significant difference?

Thanks.