Just got myself a neat wee Lezyne CO2 inflator thingy. Screw the cartridge in, press down on the valve and it inflates. Only problem is I reckon the tyre (road bike) is only going up to about 60psi. And when I take it off there’s still plenty gas shoots out. Am I doing something daft?

The gas that’s left is also at 60psi. So it won’t go into the tube but it will go into the atmosphere.

Well if it’s 60psi in the tyre, there’s 60 psi in the cartridge. When you take it off, it’s got to go somewhere!

Edit: Doh, too slow!

Yes but the problem is how do I get the tyre to around 100 psi? I hold it down but after a certain point it stops inflating.

A 12g CO2 cartridge should get you to better than 60 psi in a 23mm tyre though – more like 90psi. 16g should get to over 120psi. What are you measuring it with?

A cannister almost twice the size will do it (or use two of the ones you’ve got).

If you are just being lazy and using this to inflate the tyre at home rather than using the pump (instaed of using it as an emergency roadside fix) you need to bnow that CO2 leaks through the tube much more quickly than air does. 60psi is ok as a get you home.

It’s a 16g cartridge. Inflates so far then seems to stop. 60psi thing is a guess but it’s certainly nowhere near what 100 feels like when I put that in with my track pump. Have tried several cartridges now.

Should also add that mechanical stuff and I are not a good mix.

I’m only practising at home. However would like more than 60 in case I puncture early in a long ride. Don’t like having to ride worrying my bike tyre is down.

CO2 leaks through the tube much more quickly than air does.

Really? CO2 is a larger molecule than O2 and N2, so I think the reverse is the case.

I heard that Gas thingys leak quick than using a pump

T’net

CO2 is a nonpolar molecule. Because it is a linear molecule, the dipole moment is zero. In fact, everything in the system- tube, N2, 02 and CO2 – is nonpolar. There are other interactions on a molecular level that occur that allow the CO2 to pass through the rubber faster than the other gasses. Size of molecule is also not a contributing factor.

Wow, CO2 really does leak out much faster.

I was told CO2 was just to get you home and then to use a pump at home.

I helped a stricken cyclist with one of those lezyne CO2 inflator. It was rubbish, grabbed and unscrewed the presta valve stem and would not go on properly, nor inflate adequately. The Innovations nano-flate are far superior and a much simpler design. And go to well above 80psi without much stress.

A normal size cartridge should inflate a road tyre to 100psi give or take a few pounds. Not sure about this particular valve, the ones that screw on are a faff in my experiance, better off with the simple spring loaded push to inflate type.

The one I have is just a simple spring loaded one though. No screwing on.

Just tried again but this time tried inflating it in short bursts that worked much better.