I have an inflator and cartridges but havn't had to use one for years on my Presta valves. Now I'm getting a bike with Schraders. Will one cyclinder fully inflate a road tyre and is there any danger they will over inflate.
A 12g soda sized bulb (cheaper) will only just inflate a tyre but normally bike riders use the larger 16g cartridges and yes they are ample. The danger is actually popping the bead or getting a pinched tube because the tyre goes up so quick and freezing your fingertips to the bulb [bseg]
I've never used an inflator, but their speed seems like a problem to me. I always stop pumping at about 20psi to check that the tyre is properly seated, by giving the wheel a spin with a finger on it, before going up to full pressure.
And after getting a flat, the slowness of a pump gives you ample warning if you've cut the tyre badly enough for the tube to blow out through the hole. I've seen several people with inflators burst their spare tubes.
I agree. I have burst a few myself.
I try and consiously think to go slow take my time especially if others are standing around waiting for me to finish up and ride. I havent got a presta tyre gauge but I have wondered if maybe you can easily get the tyre up to around 150psi if you use a pump to open the tube up and a few more pumps to seat the bead before the gung-ho co2 blast up to pressure.
I find mine can inflate twice from one cylinder. I don't think they can over inflate as the pressure in the canister is about 120psi I have been told. As below, they can cause a pinch if you dont seat the tube properly.
Got a cold burn this morning inflating the road tyre after changing a flat. 2 degrees up in the hills to start with and the valve got stuck on the inflator leaving the air escaping after it was pulled off the tyre. During the process of stopping the loss of gas, the canister's temp really dropped and (cold) burnt my finger tips. Might invest in a protective case.
Most of the inflation heads are spring loaded too, so that you can add the air in short bursts. The TacX inflators have an inflation regulator (knob) to speed up or slow down the flow, but are slightly more expensive. I have not used these before though.
"I filled a regular tube/tire with a CO2 cartridge, as an experiment, to 98psi. Came back in 18 hours. It was down to 68psi. Moral to the experiment: I still don't know why, but CO2 leaks out much faster than air.
What makes it diffuse through the tube faster are the chemical properties. CO2, with the oxygen atoms connected to the carbon with double bonds, can partially bond to the hydrocarbon molecules in the rubber tube. This holds the CO2 in proximity with the rubber and it can gradually diffuse through the thin tube wall and escape out the other side into the air. N2 molecules are essentially inert wrt the rubber tube and just bounce off the tube wall, so filling the tube with nitrogen would result in even less pressure loss than using air. O2 molecules, the other main constituent of air, are intermediate - they diffuse a little more than N2, but not nearly as fast as CO2."