Bought one of those CO2 air thingys and went though 2 CO2 cartrigdes trying to pump a tire on my roadie (2 flats in one ride with crappy Michelin 2 pro race tires). I waited for a while for somebody with a real pump to lend it to me to fill the tube. It took awhile for another cyclist to come along, but he helped me pump up and saved me a 15 mile walk home in cycling shoes. I look forward to seeing this older guy again. Now I usually always bring my crank bros mini pump with me unless I am riding with others