Originally Posted by 2wheelspeeding

You can save money airing up flat tires by buying C02 cartridges for pellet guns from a sporting goods store like Dick's. All you have to do is put a small washer or a smidgeon of dirt in the bottom of the inflation device to make up for the 2mm difference in size between a cycling C02 cartridge and a pellet gun C02 cartridge. A cycling C02 cartridge goes for $3-$4 compared to a pellet gun cartridge you can usually get for about 50 cents if you buy in bulk. I have put together a lot of rides and always end up helping people with flats and have found this method to save tons of money.