I have used a CO2 cartridge 3 times on the road and wanted to make sure I wasn't doing something wrong...is it possible to get near normal pressure? I usually run around 110 and this morning I changed a ftube with a bad valve and had to ride on probably 50 psi because I wasted some air trying to refill the bad tube. The other times I used it I maybe got 80 psi out of it. I am just using the no frills head, not sure of the brand...