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Q about C02 and tire size(7 posts)

Q about C02 and tire sizeGrahamalicious
Oct 5, 2003 5:51 PM
Last night on my ride, i flatted over some railroad tracks and used my CO2 system to reinflate my tire. It was rather dark, and thought that i didn't have the new tube pinched in the rim, but i could be wrong. i used a 16g threaded cartridge on a long stem presta tube (michelin 20/23) in a bontrager race lite silica tire (700x23). The tire blew upa few seconds later, and looking at it today, there is a part of the tire missing and there is a long tear (5+ inches). is it from having too big of a cartridge or from a pinch flat or both? thanks!
Not sure what your question is, but...russw19
Oct 5, 2003 5:56 PM
On a 700x23 tire, a 16 gram cartridge should put your pressure at about 95 psi. Keep in mind that once the pressure in your tire equals that in your cartridge, the system reaches equilibrium and so it won't get any more pressure to the tire. However, that CO2 is not enough to blow up a tire unless you cut it when you flatted the first time. I would guess that what cut your tire happened before you tried to re-inflate it.

Russ
Not sure what your question is, but...Grahamalicious
Oct 5, 2003 7:35 PM
It was a brand new tube, so then i assume it was pinched in the rim? i'm asking because i need new cartridges and don't want to buy more 16g ones if there was too much for the tube
Your cartrige was OKspookyload
Oct 5, 2003 11:15 PM
Sounds to me like you had a piece of the tube pinched between the rim and tire, and if it had been light you would have seen it bulging while you inflated it. If you had cought it, you could have deflated it, repositioned the tube and reinflated. That is sort of the downfall with co2. It happens so fast, it is hard to catch a tire that isn't seated right. The violence of the bursting tube is what probably caused the tear. Of course the tear could have happened when you hit the tracks too. 16g cartriges are just fine for a 23mm tire.
Or bead not seated properlyDMoore
Oct 6, 2003 12:08 PM
It's a good idea to put just a little CO2 in, and then check to make sure the tire bead is seated properly, all the way around, before you inflate it the rest of the way.

If you have a CO2 system with a trigger, it's easy to do. If you have one of the "one-shot" systems it can still be done but you have to be careful. First, you screw the cartridge all the way into the adapter. Then, you attach the adapter to the stem. Next, you back off the cartridge very slightly, only for an instant, and then tighten it back up. That should put enough CO2 into the tube to give it some body, and allow you to check to make sure everything is seated properly. If all is well, then you inflate the rest of the way. And here's where the 16g cartridge comes in handy, because you have a little bit of CO2 to spare.

I've been using CO2 for close to a decade, literally dozens of flats over the years. I only blew off a tire once. Since I've been doing it the way I described, it's never happened again. (But now, having said that, I'll probably blow up a tube tonight!)
You should be using 12g cartridgesMR_GRUMPY
Oct 6, 2003 5:30 AM
12g cart will bring a 23mm tire up to 95 psi. A 16g cart will inflate it to 130 psi.
Either way, you probably pinched the tube when you put it in.
Let's be clear - is it the tube or the tire?Kerry Irons
Oct 6, 2003 4:48 PM
You say "there is a part of the tire missing and there is a long tear (5+ inches)." If the tire has a hole in it with a 5" tear, then you severly damaged the tire somewhere along the line and your CO2 cartridge didn't cause the failure. If it is the tube you're talking about, then this is typical for not properly seating the tube inside the tire before inflating. An easy solution to that problem is to inflate the new tube by mouth before installing the tire on the rim. That gives it just enough shape that it is very unlikely that you'll pinch it. As an extra precaution, once you have the tire mounted just work your way all the way around the rim, pinching and wiggling to make sure things are seated. Finally, if you pinch flatted over train tracks, you either were not running high enough pressure, are running too-small tires, or should be more careful to lift up off the saddle when crossing the tracks.