Tire inflation?

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Originally Posted by Bella

Because CO2 is cold, your tires will deflate by next day - don't be alarmed. Just refill by traditional pump.

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I've never had a Co2-filled tire deflate any faster than a regular pump filled one. And CO2 is all I use on the road. Maybe you didn't get whatever it was that cased the flat fixed?

Reminds me of the Sheldon Brown/Carapace posting:

redmist wrote:
>
> As far as weight and efficiency go these seem to be the way to go vs. frame
> or mini pumps. Any drawbacks?

CO2 is heavier than air, you will make your bike heavy and slow if you
use it. Helium is lighter, the only way to go if you want speed and
safety.

If you are willing to live dangerously, Hydrogen is lighter and cheaper
than Helium, but don't smoke while riding your bike if you use
Hydrogen...

Carapace Completed Umber
Lakehurst, New Jersey

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Originally Posted by bcipam

When you attached the pump nozzle, did you set the "hold" lever? In otherwise, the nozzle goes on and you usually pull the lever up (or down depending on the pump) to latch the nozzle on adn hold in the air. If you don't air comes out.

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This can be tricky to get right - and every pump is different. I'll bet this was what the problem was. Shadon, you're going to have to figure out how to get your pump locked onto the valve right.

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Originally Posted by Bella

Because CO2 is cold, your tires will deflate by next day - don't be alarmed. Just refill by traditional pump.

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Have you actually had your tires deflate the next day after inflating them with CO2? Or is this something you heard from someone else?

I ask because that's never happened to me. I've had 3 or 4 flats and used CO2 cartridges to inflate. I actually went back to using a pump when I had a rash of flats a year or so ago. I didn't like adding to the landfill and when I got a flat both front and rear at the same time (lots of glass on multi-use path in a not good part of town) it seemed prudent to not rely on my limited number of cartridges.

Anyhow... I suspect there must have been some other reason they deflated.

V.

PS After the double flat, we found a new way to get to the transit center. :D

V - I just bought my first co2 stuff and the guy at lbs said the same thing - your tire will deflate the next day with co2. Maybe you've just been lucky or temp also plays a part???

As you inflate a tire with a CO2 cartridge, the CO2 will chill through adiabatic expansion. But once the temperature of the CO2 in the tire has equilibrated with ambient, which would probably take less than an hour under most conditions and depending on the insulative ability of the tire and tube, the pressure in the tire shouldn't change. So I don't understand tire pressure dropping overnight if you got through another hour of your ride with good pressure. Anybody want to put a temperature probe in their tire after inflating with CO2?

The next day part seems a bit far-fetched - doesn't take very long for a gas to cool or heat to the surrounding temperature, and the pressures in a road tire wouldn't be significant enough to have any great affect on this. :confused:

(i.e. What Deb said, but with smaller words. :p)

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Originally Posted by mtbdarby

V - I just bought my first co2 stuff and the guy at lbs said the same thing - your tire will deflate the next day with co2. Maybe you've just been lucky or temp also plays a part???

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That's really crazy - I have never heard of that happening and no one on my team has ever had this happen. My tires stay inflated for weeks with CO2 filling. I don't even need to top them off within a week's time.

Now if you are using latex tubes, your tires will deflate overnight.

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Originally Posted by DebW

As you inflate a tire with a CO2 cartridge, the CO2 will chill through adiabatic expansion. But once the temperature of the CO2 in the tire has equilibrated with ambient, which would probably take less than an hour under most conditions and depending on the insulative ability of the tire and tube, the pressure in the tire shouldn't change. So I don't understand tire pressure dropping overnight if you got through another hour of your ride with good pressure. Anybody want to put a temperature probe in their tire after inflating with CO2?

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And I'd bet it would take less time for the temp to get to ambient thorugh brake heating and rotation.

just a few more thoughts:
if a tire is inflated with cold gas, and then warmed up, the gas pressure will increase (like leaving your bike in the hot car on a sunny day.... the tire will explode eventually). If you fill your tire with He (I hope no one was planning on this anyway....might also get a little costly) the He will diffuse through the tire walls really really fast... and this really doesnt help out on the road.
Petra

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Originally Posted by mtbdarby

V - I just bought my first co2 stuff and the guy at lbs said the same thing - your tire will deflate the next day with co2. Maybe you've just been lucky or temp also plays a part???

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I've had this happen to me a number of times (in 2004 I was getting 1-2 flats everytime I rode....crappy stock tires couldn't even handle 1000 miles). I get a flat on my road bike, change the tube and inflate with CO2. I ride home and all is well. The next day, that tire will be flat as a pancake. I pump it up and and I'm back at it again. I've never understood it.

I guess we have special CO2 in California then. :D

V.

Remember you have to match the source of the CO2 to source of the tube. French air for your Michelin tubes, Italian for Torelli tubes, English for the Contis, etc..

What if I have Conti tires & Michelin tubes? :confused: World War III underneath my saddle! :eek:

We may have to call for a UN sanction and send in some peacekeepers.

I had never heard of that until here ... and then last week on the ride some of the guys were talking about it happening to them. They thought that CO2 went through the tire faster than regular air - the rule of thumb was that if you used CO2 you should always empty and refill with regular air when you get home.

I wanted to use helium last week to lighten up.