wee gears
So is it just an alternate gearing choice, or are there other benefits?
Compact gearing =
-Lesser overall weight from: 2 vs. 3 rings, 2 smaller rings vs standard double, and a shorter chain.
-Better chain line and better shifting than a triple.
-With a 34/50 and a 11-26 (vs. a 39/53 and a 12-27) you cover nearly every situation
-Many companies are replacing triples with compacts across the board.
Perhaps a possible downside is that with lesser teeth spinning they could wear faster.
A compact frame geometry is something completely different. Say you ride a 56 cm level top tube bike. It might be square with a 56 ctc (center to center) top tube and seat tube length...
In a compact frame the seat tube length might only be a 45 while the effective top tube might still be a 56. The wheelbase and the general way that the bike rides and works will be the same. You will need a much longer seatpost but the saddle height and cockpit length remains the same.
A compact geometry might look a lot like a mt bike with a sloping top tube. This can give a lower center of gravity, more stand over clearance and a sort of funky look (at first glance).
Giant was the first to go mainstream with this setup and now it seems that everyone is doing it.. Even Colnago.
j-