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Old 09-21-05, 03:58 AM   #1
Jeff Hoffmann
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I normally inflate my 700 x 23 Vittoria Open Corsa tires to 120-130 psig with a pump and Silca valve. They are rated for 150. I was in a hurry the other day and used a 16g CO2 cartridge to top off both tires. Felt right (before I had a chance to check with a gauge) but as the CO2 went from very cold to room temp (Charles Law - yes I know) it expanded and a few mintues later the front tire went off like a .38 special. I was a bit surprized the bead came off the rim, but was VERY surprised that it bent the rim (Bontranger Race Lite 20 spoke on a Trek Moadone 5.2) with a runout of about 3/16". Got it true again to +/-1mm.

Was the bent rim expected and just the result of the light weight rim?

I have had several blow pressure blow outs (even with 180 psi Continentials I used to run at 200 psig for TT's) even when riding but never a bent rim [???]
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Old 09-21-05, 08:27 AM   #2
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How old and how many miles on the rim? An old, worn rim might be easily bent because the brake track is much thinner from abrasion than when it was new. Light rims have little reserve metal to start with.
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Old 09-21-05, 09:14 AM   #3
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12 gram is better for 700 x23 tires. You can safely dump in a full cartridge. I put about about 10 psi in mine with a pump and then dump a 12g in for about 100- 110 psi in the hot weather. A little less when it's colder. The temp makes a big difference.

You said you "topped off" the tires. If they had much air in them at all you went way over the limit. Did you measure what was in them first? You need to know what you have to start with.

Wheels have a maximum psi limit too. They may not be up to the tire limits.

Innovations has a size / pressure chart on the web site.

Last edited by 2manybikes; 09-21-05 at 09:20 AM.
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Old 09-21-05, 02:02 PM   #4
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For my 700X23 tires, I only get about 95psi from a 12g cartridge. I get 125 or so from a 16g. I am heavy enough to want higher pressures so I always use the 16g cartridge. I have never had the problem that you relate.
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Old 09-21-05, 02:08 PM   #5
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I do the same as above.. I use my mini pump and put about 15-20lbs in the tire, make sure it is seated correctly then use a 12g co2 to top it off.. I usually get 110-120lbs which suits me fine
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Old 09-21-05, 08:21 PM   #6
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The CO2 did not cause the tube to blow. Most likely you had the tube pinched between the tire and the rim, or the rim was damaged or severely worn.
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Old 09-21-05, 08:27 PM   #7
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Tube pinching won't blow like that-it pinches and rapidly deflates causing no damage. In this case the tire was not properly seated. Did this blowout occur between pairs of spokes?
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Old 09-22-05, 07:35 PM   #8
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Quote:
Originally Posted by Waldo
Tube pinching won't blow like that-it pinches and rapidly deflates causing no damage. In this case the tire was not properly seated. Did this blowout occur between pairs of spokes?
If it's not properly seated it's most likely because the tube is pinched between the tire and the rim.
KERPOW!
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Old 09-22-05, 08:41 PM   #9
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Quote:
Originally Posted by Al1943
If it's not properly seated it's most likely because the tube is pinched between the tire and the rim.
KERPOW!
If the tube is pinched you won't get enough air pressure into it to get the tire seated before the tube punctures. Even in the rare occasions where I've seen someone get it up to pressure while pinched, the resultant deflation of the tube wasn't anywhere near sufficient to cause the scenario the OP described.
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Old 09-22-05, 09:09 PM   #10
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Quote:
Originally Posted by Waldo
If the tube is pinched you won't get enough air pressure into it to get the tire seated before the tube punctures. Even in the rare occasions where I've seen someone get it up to pressure while pinched, the resultant deflation of the tube wasn't anywhere near sufficient to cause the scenario the OP described.
I'm sorry but I don't understand what you are trying to say. It doesn't make any sense to me. There is nothing about a pinched tube to keep it from being pressured. What is your definition of pinched?
I've had 120 psi in a pinched tube, right before it blew.

Al
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Old 09-23-05, 06:04 AM   #11
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Quote:
Originally Posted by Al1943
I'm sorry but I don't understand what you are trying to say. It doesn't make any sense to me. There is nothing about a pinched tube to keep it from being pressured. What is your definition of pinched?
I've had 120 psi in a pinched tube, right before it blew.

Al
Nothing to keep it from being pressurized except the fact that it's pinched and will rupture when it reaches a certain pressure. Same definition you're using.
I've been fortunate enough to be around for literally thousands of flat tires and have witnessed these sorts of things many times. I can count on one hand the amount of times a pinched tube was able to get to any significant pressure before rupturing. Cannot recall a single instance where this occurred with sufficient force to cause the damge originally reported. Seen more than a few occurrances of a bead not seating properly due to a variety of other factors and that can result in the sort of thing the OP described.
It seems we are going to have to agree to disagree.
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