[QUOTE=wirides;16069954]Surreal, that is extremely helpful, thank you. I considered that but I was left with the impression the crank swap would give me a better climbing ratio and it appears it does. What I don't know is how the numbers translate to real life. Here's the thing, I am basically finding myself at or near the top of the cassette in the big ring or too far down the cassette while in the small ring. I am trying to accomplish too things: 1) better / easier climbing and 2) find gearing that will put me more in the middle of the cassette during my normal riding conditions.[/QUOTE
play around here:
http://sheldonbrown.com/gears/ You'll find it offers you to play with the theoretical math without spending any money, but of course there's no substitute for actually riding a given setup. TBH, even if it weren't cheaper and easier, I think the closer-spaced ratios of the 53/39x12/28 would be preferable to going compact-- it obviates the highest and lowest ratios given by the 50/34x11/26, and gives you more to work with in the center of the cassette. Plus, if you're already spending a lot of time in smaller cogs while on the 39t ring, moving to a 34t ring will just exacerbate that problem.