Curiosity got the best of me, and I decided to test the viability of using Co2 cartridges to fill Endomorph tires. So I fully deflated both Endomorphs on my Pug after last night's ride through the slush-filled park. Then, I used the entire contents of a 40 gram Genuine Innovations CO2 cylinder, with a Planet Bike Red Zeppelin inflator head, to put 6.5 PSI back into the rear tire. Two 16oz Planet Bike CO2 cartridges brought the front tire up to 6.5 PSI using the same inflator head. I prefer to run 18 20 PSI on the road, so I assumed the position and put 240 pumps, from the Topeak Mountain Morph, into each tire to get them up to road pressure for the remaining portion of my commute home.
CO2 is not a great option for Endomorph inflation UNLESS you are really lazy, have money to burn, broke your pump, are in a big hurry (competitive racing for a huge wad of cash or late for a fancy dinner with Celine Dion at Olive Garden), or absolutely have to find out how foolish it is to carry CO2 cartridges in lieu of a good high-volume pump. At a retail level, one would have to spend $12.00 - $15.00 to get off the trail at 6.5 PSI. That's damn squishy and slow on anything but soft/loose snow or sand. 6.5 PSI sucks on hard surfaces. It would cost $25 - $30 to get up to a reasonable road/hardpack pressure. Though the price goes down a bit if you buy cartridges in bulk, CO2 is a poor substitute for a decent pump or reliable riding partners who carry decent pumps and whiskey.