# 12g CO2 cartridge enough?



## aclinjury (Sep 12, 2011)

is 12g enough to get a 23c tire to 90 PSI reliably every time? (I'm using a Portland Design CO2 inflator which does not seem to leak air like many other inflators do as you fumble around). I'm 130 lbs and 90 psi is all I need. Seeing how a 12g cartridge is like half the price of a 16g cartridge, I'm considering just using the 12g one.

thoughts?


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## pmf (Feb 23, 2004)

That's what I've used for years. Plenty of pressure to get you home. Save some money and buy them either on-line or at a sporting goods store that sells air gun stuff. The prices that bike shops want for these things are outrageous. You should be able to get them for less than $0.50/cartridge.


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## flattire (Jan 29, 2004)

I've used 12g cartridges for years. They have always worked well for me in 23 tires.


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## cdhbrad (Feb 18, 2003)

Before I switched to Lezyne frame pumps on all my bikes, I always used 16g CO2 cartridges. Now, I never worry about having enough air. Came in handy on a group ride yesterday when someone flatted and didn't get enought air in the tube from their CO2 cartridge....they used my pump to top it off.


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## Doc_D (Mar 16, 2006)

When I went to c02 a few years ago I did a test with 12 gram cartridges and only got about 70 psi if I remember correctly. So I carry 16 gram cartridges. I also suspect they don't work as well in cold temps.

Your best is to test one. Besides if this is your first experience with C02 it's a good idea to figure out how it works in your garage rather than roadside in a rain storm.


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## aclinjury (Sep 12, 2011)

Thanks for the input guys.

I also carry a Lezyne pump that I can get to 90-100 psi, but it does take me 5+ minutes of pumping, which is no problem if I'm in no rush. But in a group ride, guys get impatient waiting so I'm considering carrying a CO2 cartridge for fast action. Those 16g cartridges are so damn heavy in my rear pocket, that's why I'm considering 12g. Plan is to use the hand pump to get about 20-30 psi into the tire (getting to 20-30 psi quick, it's getting to 90-100 psi that's tough), then top it off with a 12g cartridge.


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## Herbie (Nov 12, 2010)

I don't know what the pressure is from a 12 oz. but I have never had any problem. I also rarely get pinch flats. I suspect if you are careful not to hit potholes hard you will not have any issues. I do have mini pump on the bike as it makes it easier for me to find the cinders that seem to cause most of the flats around here. If I thought it necessary, I would probably start by putting some air in the tube and then using the CO2 to finish.


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## BlueMasi1 (Oct 9, 2002)

What @pmf says. I buy in bulk from Walmart and comes out to about .44 cents per cartridge. It will inflate my tire well enough to continue my ride and get home.


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## danl1 (Jul 23, 2005)

I used to use 12g's, would pretty consistently get @85psi. Which was plenty to get even my 185lbs home, if a few psi short of ideal. 

But hang on a second. Portland AFAIK only makes threaded CO2 devices, and threaded 12g's are somewhat harder to find (and don't have as much of a price delta as compared to the "Wal-Mart" solution, which is usually to buy the unthreaded airgun carts.

If you've a 12g threaded source that's significantly cheaper than their 16's, go for it.


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## velodog (Sep 26, 2007)

I prefer the 16s myself and this is about the cheapest I've found threaded cartridges.

16 Gram Threaded CO2 Cartridge - 12 Pack: Amazon.com: Industrial & Scientific


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## bigbill (Feb 15, 2005)

I used a 12g in a 25mm tire yesterday and rode 14 miles home. It was my second flat, I used a 16g on the first one. You can run larger tires at lower pressure, a 12g was fine. I live in a small farming town in Texas, you either mail order threaded 16g online or pickup a box of 12g at Walmart for $4.50. My inflator takes threaded or unthreaded but a 16g must be threaded to work.


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## latman (Apr 24, 2004)

no matter what size you use(I prefer 16g) i suggest deflate it whaen you get home and pump it up with a regular pump as the smaller Co2 molecules leak out of butyl tubes a lot faster than regular air (mostly nitrogen)


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## danl1 (Jul 23, 2005)

latman said:


> no matter what size you use(I prefer 16g) i suggest deflate it whaen you get home and pump it up with a regular pump as the smaller Co2 molecules leak out of butyl tubes a lot faster than regular air (mostly nitrogen)


Good advice, practically speaking, but not because the molecules are smaller. N2 molecules are smaller than CO2. But CO2 is more soluble in rubber, so can effuse through more easily than the other gases. 

Velodog; that's a good price, especially on a reasonable quantity.


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## ScooterDobs (Nov 26, 2010)

I always wondered why my CO2 inflated tires lost pressure, I thought it had something to do with the temperature or something! I use WalMart 12 gm cartridges. I found that if I lick the top of the cartridge before putting it in the inflator it made a better seal and I could get about 80-90 psi in the tire. I ride at about 110 so it's close enough. Enough to finish the ride, get home, bleed the tire, and inflate with the compressor. I'm going to bleed the tire anyway so I go cheap.


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## aclinjury (Sep 12, 2011)

On Ebay, you can get 50 threaded 12g CO2 cartridges for $34 shipped. 100 cartridges for $60 shipped. Me and a bunch of guys chipped in and got a 100-box. 
$.60/cartridge (threaded) is great.

And this is food grade CO2, not air gun graded where you can have oil inside the cartridge and may cause the butyl tube to dissolve


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