CO2 inflation
 

I have a pump onboard, but also thinking of getting a CO2 inflator for faster recovery during long group rides.

Anyone recommend a specific brand?

Also, how many cartridges does it take to inflate up to ~110psi for a 700x23c? Just curious, as it seems most of the inflators don't have a pressure gauge. What's the best way to tell?

I use a air chuck small and simple but does the trick. I can get 2 tires out of a 25g cartidge. Never tried a 12g, but I would imagine 1 would be enough for a tire. I carry a small pressure guage with me.

So, an extra little gauge is useful I can se that. hmmm... Wonder if I can get an inflator with a little pressure gauge built in? I'll dig around a bit.

My cartridges give me two inflations if the second time I use it, is reasonably soon after the first. The seal leaks and eventually the thing empties.
You need to be careful when inflating the tyre that you dont over inflate and blow it out of the clincher groves like I did first time. :(
Now I just inflate till I think it's hard enough to get me home.

I can see where that is a porential problem. I think the thing to do is one of three things, so correct me if either one is bad idea.

1. Use a complete 12g cartridge, to end up where you want, without a gauge to check psi.

2. Carry a pressure gauge and check, when using bigger cartridges.

3. Try to find an inflator with a gauge built in. Does anyone sell one like this?

a 12g cartiridge will get you close to 100psi.. a 16g cartridge will get you to 125psi.

You can get 12g cartridges real cheap at walmart, 3.50 for 5 cartridges..

I carry a pump and a co2 inflator.. Make sure the one you buy will accept 16g catridges, some do not..

Just came across this. Thought maybe it would be better to get this, and just use the pump I have for the MTB's. I kinda like this one, cuz it's both in one, and takes the 16g cartridges. Although my Michelins have a max of 110psi. Wouldn't a 16g be a bit too much? Wouldn't want to blow out the bead by accident.

http://www.nashbar.com/profile.cfm?c...eid=&pagename=

Any opinions on this one?

I have read that the pump part of this CO2 device is virtually useless. But I hve never used it myself. I use the innovation CO2 pump that accepts both threaded and non threaded cartridges. I purchase the catridges at walmart. I als carry a torelli aria mini pump. I may run out of CO2, tubes and patches bit I will NEVER run out of air :D

I like to carry as little as possible when riding/training and given that I seldom flat (probably have a spate of 'em now) and I have my cel to contact my wife if I'm in trouble, I look at puncture stuff as the very minimum to get me through an emergency.

You're not huffing the stuff are you? Try the whip cream cannisters.

Check out Planet Bike's Red Zeppelin inflator. Its got an on/off valve, its small and fairly light. Carry a 16g cartridge. You don't need a gauge. Fill the tire up and go.

Couple of suggestions:

Get the CO2 inflation made by the brand "Innovation" http://www.performancebike.com/shop/...tegory_ID=4362. I have used it from day one and works great.


Please remember to that the CO2 is a temporary fix to get you home. The CO2 molecules are much smaller than the good ol' oxygen and will leak out of your tire (at what rate, I don't know). When you get home...or get to where your getting, and you have access to a regular pump, drain the CO2 and put in regular O2.

*Bling*
http://store.bianchiusa.com/cgi-bin/store/H8240.html

I think I gotta get me one of those. :D

pfknob as a chemist that is insulting.

1) Air is mostly nitrogen (~70%) not oxygen.
2) The molecular size of CO2 is larger than that of O2 (you know the added carbon?)

O-O bond length = 174nm

O=C bond length is 120nm
so for C=O=C total length is 2x120nm = 240nm

3) The reason some say to put plain air back in is that C02 weighs more than air.

C=O=C?

You mean O=C=O?

Just being compulsive. ;)

D'oh

Another chemist here...

The reason to reinflate once you get home is that CO2 is much more soluble in the innertube's rubber and "seeps" out. I used to have a link to that fact but I've lost it...

<edit> found the link: http://www.madsci.org/posts/archives...2329.Ch.r.html

Well, I think pfknob meant air and not O2. And although it's been a while since my college chem classes, I believe CO2 molecules are smaller than air molecules. But really as mentioned previously, CO2 is more "soluble" in rubber because they are in fact attracted to the chains in the rubber whereas those same chains actually repel other types of molecules. Note - I am not a chemist.

Khuon, it's gotta be the solubility thing if CO2 truly leaks faster than air, since air is made up of O2 (molecular weight 32) and N2 (molecular weight 28) while CO2 (molecular weight 44) is a larger molecule. To address Patriot's question, I have the Second Wind CO2/pump, and my plan (fortunately haven't had to use it yet) is to use the hand pump to get the tire started and then a 12g cartridge to fill the tire since I want about 110 psi. It's a fairly compacct unit, but if you don't use the whole cartridge, you waste what's left since you have to remove it to get the unit back to it's compact size. Otherwise, the pump handle and housing have to be carried separately.

Molecular weight has no bearing on molecular size so there's no use in including it in the discussion.

Good one F1. But as a general observation to a non-chemist the weight is a good indication of size. Only in isolated atoms or simple diatomics does it have no bearing. Feel free to explain effective nucear charge to the group as to why it doesn't always hold; but it's an ok rough measure.

Regardless, it's a bogus thing to let the CO2 out. Geez, CO2 leaks out, you put some air back in. Eventually everything is copacetic. What serious roadie doesn't pump his tires every time he rides anyway?