Originally Posted by carpediemracing

+1 on the rider being the main source of weight (not to state the obvious but I outweigh my bike by a factor of 10+).

What would affect center of gravity is how my weight is distributed. Since BB height, bar height, and seat height are virtually identical, my center of gravity is virtually identical.

If I took a picture of me on a bike (from the side) and erased all the frame/stem/post bits, I could redraw the frame which ever way I want using the same head tube angle, rake, and bar/seat/crank position. As long as the bike is about the same weight/stiffness, I still have some range of motion, the bike would essentially handle the same. I could be on a frame that resembles a BMX frame (which I think would be ideal for me due to tiny main frame and long front end which matches my gorilla like limb proportions) or one that was standard.

Compact sizing allows a wider range of leg lengths to fit on a given (lengthwise) length frame. In other words, if I wanted to ride a 55.5 cm top tube, I'd have to buy a pretty tall frame (54-55 cm). I have short legs and ride a 52. Therefore I could not fit a "standard" frame with a 55.5 cm tt. But, with compact, I could buy a (for example) size M Giant. It has an approx 50 cm seat tube and I can both stand over it as well as have the seat at the right height. No way I could do this on a standard frame.

Having said that, I first went to a size S Giant (53.5 tt) and then recently I moved to a 52 cm standard (53.5 tt also, but 1 cm shorter head tube).

If I were a team director with a lot of different riders (Slipstream), I'd want spares that fit as many riders as possible using the fewest bikes. A compact frame would allow me to fit more riders onto a frame without compromising their fit too much. For example, if my team had all Cannondales, I'd have to carry around frames like 52, 54, 56, 58, 60 to fit most riders. If my team had all Giants, I could get by with just M and L, maybe XL too. Even if a rider really mangled his primary bike, a mechanic could do a stem swap to adjust the spare bike's fit more precisely (or use an adjustable stem).

Any difference in handling etc has to do with things that have nothing to do with standard vs compact. It has to do with tube specs, stiffness, etc. My compact Giant TCRs are *way* more noodly than my standard Cannondale.

cdr