one 16g or two 12g?
2346
Member
1243 days
Triguy98 posted 1 year ago.
Stick with the 90, otherwise you risk popping a tube. It sucks when you blow your spare and you're 20+ miles away from home/ car- right, Chris?
Life is short. Play hard and get dirty doing it.
1125
Member
897 days
UFTriGator posted 1 year ago.
It'll inflate until the cartridge and tire reach barometric equilibrium. Each successive cartridge that you attach to a tire will add less and less pressure, so it won't give you 135, but you'll probably get over 100...I just wouldn't want to risk popping the thing. You seem like you know math stuff, so think y=e^(-ax). I know that I can get more than 90 psi out of a 16g cartridge, though, so I think you should just try a different brand of cartridge.
______________________________________________
-Matt
Not fast enough.
35
Member
414 days
gh posted 1 year ago.
Yeah, not sure how I thought I'd empty the cartridge - the physics doesn't work like that no matter how hard we try...
I've been using the GI cartridges from the LBS, but at $3.95 a pop I'd be wise to seek out a less costly, quantity source. I also forgot to mention that I'm running on 700x25. Which brand of cartridge do you use, Matt?
1125
Member
897 days
UFTriGator posted 1 year ago.
They're called Innovations. (I had to open up my saddle bag to find out....I really had no idea). I also use 23c tires, which could account for the difference, too.
______________________________________________
-Matt
Not fast enough.
35
Member
414 days
gh posted 1 year ago.
Same cartridge, so tire size is the difference. I did find one online source that gets me down to ~$1.77 for the 16g size and ~88 cents for the 12g, so I'll get some of each and see if there's a combination that gets me up to 120ish.
I've been thinking about the thing about the CO2 leaking out faster than air. CO2 is a larger molecule than both N2 and O2, so molecular size shouldn't be the issue. Could the whole problem be a function of the sealing surfaces contracting when they get cold? If that's the case, would it eliminate the leak if the valve stem were tapped in order to reseat the sealing surfaces once everything warms back up?
One 16g co2 will get me to 90 psi, but I hate to run that low and risk a pinch when I have no more co2 or tubes on me and I'm a long way from home. If one 16g co2 cartridge gets me to 90 psi, will two 12g cartridges get me to 135?
90 psi / 16g * (2 * 12g) = 135 psi
Or does co2 not work proportionally like that? (FWIW, I normally inflate to 120 psi)
Glen