For road-side tire inflation needs, I haven't carried a pump in decades. My back-pocket tool kit includes one CO2 cartridge and an adapter. If I get in trouble after that, I have a cell phone. On longer rides in more remote areas, I might add another cartridge or 2 to my payload. Filling up a typical 25mm road tire, I don't worry about regulating how much CO2 I'm putting in. It's one cartridge, all-in, and then pull it off quickly so I minimize any losses.
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