I race on the track. My Specialized road bike is a 58cm and my custom track bike is a 57cm. Minus 4cm would be reeeediculous.

The comfort vs non-comfort comes in to play with the seat tube angle. A more upright seat tube ROTATES the rider (and his cockpit) forward which gives track sprinters that stereotypical DEEP and LOW stance. Contrary to popular belief, they aren't hunched over any more than the roadie on the road, he's just rotated forward according to the bottom bracket. "Relaxed" geometry refers to how far back the rider is from the bottom bracket. Road riders sit back and evenly balance their weight on their butts and take the strain off the arms. Same for track endurance riders. But track sprinters are rotated forward giving the deep drop in the handlebars and stuff. The REALLY loads the weight on the arms and shoulders, which isn't a problem being that most sprint races are done in less than 5 minutes. No man can ride a 100 mile road race in that position. So, this is why when folks build conversion track bikes with relaxed geometry (saddle is way back behind the BB) and they put on deeeeep drop bars, the bike is totally uncomfortable and they fold up their bodies trying to ride it.

Head tube angle and fork rake are also different on "sprint" track bikes. They feel really twitchy at low and moderate speeds, but at +40mph they handle like a sports car, nimble and sure.

To see what aggressive sprint geometry is, refer to the LOOK 596 geometry specs. My Tiemeyer is quite similar (actually a tad more aggressive seat tube angle): http://www.lookcycle.com/en/us/piste...ack-frame.html