I really dislike CO2. I have had a couple of defects, or bummers, whatever you might call them. New canisters that are empty though never used.
I remember doing a century with a guy who swore by CO2. He had 2 on the ride. Ended up losing the air in his tire, goofed another. Ended up borrowing my frame pump right after a debate on CO2 vs pump.
Now I use the Lezyne chrome pump (model ?). It gets me up to 90 psi which is enough to get me off a mountain road and finish a ride. Fits nicely on the bike. Sadly the modern bikes have a radius in the top tube so it's hard to carry the old Zefal pump that allowed me 110.
As far as the OP, if I lost 5 or 6 pounds (maybe more) going from a commuter to a light roadie, I don't think I'd sweat a few extra grams on a pump.
