bagel007

Right. After 5 hours the tires will be too soft. But if I'm 20 miles from home, CO2 will get me back.

Tabor

I use a Planet Bike Air Kiss... super small and pretty inexpensive. I like it (used it just last Thursday).

operator

I did a test last week. Pumped both my tyres up from scratch with c02. No noteworthy deflation after a week, at least nothing substantially more than with regular air.

johnny0

my road tire tubes leak co2 far quicker than air. it takes only one day for the co2 filled tire to feel too soft to ride. i just pump it back up without letting the co2 out.

DanteB

I carry a microflate, 6 cartridges, 2 tubes, patch kit and levers. I do double and triple centuries, that's why I carry 6 and 2, and never had a problem with using CO2. I haven't had any problems with cold cartridges or leaking CO2 and soft tires while riding. I find them very easy to use.

maddmaxx 

I'm not an expert, but I was quoting from an ongoing series of articles from Velo News. This one from Feb 3 2009 may prove interesting.


https://www.velonews.com/article/8717...ules-and-short

I've been told it was true by no less than (our local triathlon legend) Dave Scott. Wading through the web yields some insights on tire pressure loss from tires/tubes inflated with carbon dioxide (CO2) cartridges. Two polymers are used for bike tubes; latex rubber and butyl rubber (isobutylene rubber).

Butyl rubber dominates the market and is used for almost all tubeless tires and bike tubes as its permeability to air is incredibly low — butyl tubes have only 10 percent the leakage rates of natural latex rubber tubes.

Permeation by diffusion predicts gas leakage rates proportional to the inverse of the square root of their molecular weights. Using air as a reference the predicted leakage rates for common gases are: helium 2.7, air 1.0, nitrogen 1.02, oxygen 0.95, argon 0.85, carbon dioxide 0.81.

It turns out however that the leakage rate of CO2 is huge, and the reason is that it is actually soluble in butyl rubber and is thus not constrained to normal permeation loss, it can transfer straight through the bulk rubber resulting in severe tire pressure loss on the order of a single day. CO2 is not likely to be replaced by argon or other gases in refill cartridges, however, because CO2 is much more easily liquefied than other gases and can be contained in a moderate-pressure cartridge in a patch kit. An analogous cartridge holding N2 or argon (non-liquified gas) would be dangerous and would require a thick (and very heavy) steel-walled storage vessel. A reference dealing with CO2 transfer through latex rubber sheds light on the loss process.

bagel007

Does anyone understand these Inflation Charts: https://www.genuineinnovations.com/bi...late-plus.html ??? How to apply them to my bike's tires? (700 x 38c (40-622), inflation pressure 50-75 P.S.I.). How many cartridges do I need to inflate my tires?

Once, the point is if one cartridge is enough to fully inflate my tires and CO2 will leak within an hour to the point I cannot ride the bike (w/o demaging it or it's dangerous to ride it with underinflated tires) and I have with my three cartridges -- I have 3 hours to get "home" safely.

I don't care if CO2 will leak overnight. For that I have the floor pump.

I want to see the worst case scenario why not to plan on using CO2 in emergencies (having flat tire).

Al1943

The chart doesn't fit your tire size (or mine) exactly but I'm sure the 16 gr threaded cartridge will fully inflate your tire. Hold the inflater so that the gas goes straight into the stem. Inflate the tire slowly. With the MicroFlate you can control the inflation rate by turning the cartridge on the threads.

johnknappcc

I don't mean to be a pest here, but as I understand it, you purchased the best frame mount pump you can. So even if the pump is a little heavy (which shouldn't matter on a hybrid anyway), why not just use that? CO2 is fine, but you seem very concerned about the use. Just stick with the pump, otherwise, the only way to know for sure is to fully flat out your tire, and then see how many cartridges you can get away with to make for a comfortable ride home.

Also, like Operator said, everything leaks eventually, so I wouldn't worry about that.

StanSeven

New bikes haven't had built in pegs for frame pumps foy years, most people think frame pumps distract from the bikes looks, they are big and relatively heavy, they can come loose and cause a crash if you are riding in a group, and most people have to resort to velcro straps to secure them.

As far as practicing first, just read the instructions. Its simple. If you have doubts, then go ahead and try it at home.

The advice about having a pump just in case pertains to a mini pump you carry in a pack or jersey pocket.

Retro Grouch 

That's my experience too.

My tires easily retain pressure for long enough to get home, but certainly not for the week that Operator reported.

Al1943

+1
I pump my tires before each ride anyway.

Panthers007

I bet I'd make a mint of $$$ if I were to market Hydrogen-cartridges. At 1/14th the weight of air - the 'Weight-Weenies' would be swarming me with orders.

I'll call myself - The Big-Bang Bicycle Company. I'll get a P.O. Box in Lakehurst, New Jersey. Want to buy stock?

bagel007

Interesting review of Innovations Ultraflate Plus CO2 Inflation System (Amazon):

"On a cold day, below 40F, the cartridge pump could be almost useless. I've had some luck with keeping the cartridges in a pocket close to my body so that they're warm when I use them, but can't say conclusively that it works. They will, of course, ice up as soon as the gas is released, but warm gas takes up more space--remembering Science 101 from junior high. "

shelbyfv

The CO2 gadgets are cheap, just get one and see if you like it. It seems you may be an easily agitated sort, in which case I suggest trying the CO2 at home. It releases pretty abruptly, don't want any roadside mishaps!

dwr1961

If you need that explosive move to put you ahead of the pack... If you really want to get big air... If you've always wanted to be "up the road"...

Panthers007

You're hired! Meet the new director of marketing.

dmp

Nice bike shoes!!

On a more serious note, I have a micro inflator made by RavX that is very similar to the one previously pictured that has worked just fine. Its spring loaded, so gas only flows when you push it in- just make sure that it is seated on the valve stem properly.

johnknappcc

I wear them on all my rides, just don't tell my wife!

calyth

I have that one, and it works just fine with me.
Just remember to pump it with air afterwards. CO2 is permeable to butyl rubber, so it will leak fast.

Panthers007

While some here are saying that CO2 leaks out of the tire/tube - maybe it's not CO2 that's causative. I am assuming that people didn't stop riding, hopped off the bike, and decided to fill their tubes. Perhaps the culprit isn't what particular gas one's using - maybe it's the patch on the tire (assuming you had a hole in the first place). Or another small hole in the tube that was overlooked.

As someone quite trained in the sciences of such critters as gases (I'm a chemist), I can't for the life of me figure out why CO2, and not plain, old air, would leak.

embe

CO2 pressure goes up and down with temperature.. it's why compressed air is more ideal, it's less volatile. For a road side fix, co2 is quick and easy to get you up to 100psi and get you going again. Fix it when you get home and you're set.

I carry a co2 inflator and 4 12g's

Mike

Al1943

The "experts" say it's because CO2 is more soluble to rubber than air. I'm not a chemist either but this is the common accepted explanation. It is true that CO2 leaks out faster than air, but both leak out through the rubber. My tires will loose at least 5 psi of air overnight, or at least 50 psi of CO2 overnight and usually more. Still, CO2 is my choice to carry on the road.

bagel007

Do you guys carry a pressure gauge along with CO2 inflators or pumps?

I have Topeak Morph G (with gauge) that I purchased just recently and it's terrible for measuring tire pressure. BTW, I haven't mounted the pump on my bike yet ... I'm afraid the brake wire that runs under the top tube will be affected by the mounting assembly. At this point I'm considering to return the pump and instead buy CO2 inflators to be covered in case of flat tire. My old floor pump will suffice for all the rest.

demoncyclist

No gauge. Fill it with a proper floor pump, and press the tread towards the rim with your thumb. Do this every time, and you will get a feel for how firm your tire should be at your chosen pressure. As for mounting the pump, they make a piggy-back clip that mounts next to your bottle cage. Far neater than the stock bracket, but even that will work- just make sure the straps are between the brake cable and the top tube, even if you have to mount it slightly off center. If you really want CO2, the Ultraflate works really well. I have never had any issues with it, and you can use any cartridge- threaded or unthreaded.