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Tire pressure-road bikes

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Old 08-16-03, 03:55 PM
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sebring
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Tire pressure-road bikes

How much pressure do you put in your tires. My original bike tires said up to 130 PSI. My new ones recommend 115-125. I tried to pump up my tubes to 120 which caused them to blow out. The blow out actually blew out a hole in my tire which is the reason I bought the new ones. I even ran my fingers around the tube to make sure nothing was in it. I tried with my new tires to go 120. Again so as I put the wheel down it blew out. With the original tires, it only did this with the front wheel. The new tires I pumped 115 into both to be safe after the front blew out. Any ideas would be appreciated.
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Old 08-16-03, 04:04 PM
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There must be something seriously wrong with either your pump gauge, how you have the tires mounted, how you mount the tires, cheap tubes or something else.

Most road bike tires are designed to carry about twice the recommended pressure on the side of the tires.

I pump mine to the recommended pressure (generally 120 psi) and have never had anything like you describe happen.

What kind of tires, size, more info, please.

Do you damage the tube upon mounting the tire? Or do you damage the tire?

Most unusual.
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Old 08-16-03, 04:05 PM
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I ride an older touring bike with 27x1/8 tires. Because the of the nature of our roads I use the thorn resisitent tubes. My tire say to go to 110 and I tend to run 105.

So far so good. In the past several years only 3 flats, 2 related to sharp objects and 1 when the old tire sidewall actually gave out.

Might check with your LBS. I am sure others will have suggestions.
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Old 08-16-03, 04:12 PM
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I use 700 x 23 tires/tubes. I use regular tubes, nothing special. This occured with both Bontanger and Specialized tubes. I was using Specialized Turbos which came with the bike. Today I installed Turbo Armadillos. This problem occurred with both tires. As far as I can tell, I don't damage the tube installing them. I didn't damage the tire, but the blow out caused a decent sized hole which is the reason why I bought the new ones today. I am very careful installing them and do not use any tools to do so. I doubt the tire gauge is bad since it's a pump mounted gauge which I bought yesterday. I ran my fingers on both the tire and the rim making sure there was nothing sharp. Like I said this only happened with the front tire. Yesterday which is when this all happened, I had the rear at 120 I believe, maybe 125 and used it on a trainer with no problem. I didn't pump it that high with the new tires because I wanted it to match the pressure of the front wheel.
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Old 08-16-03, 04:16 PM
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I guess it is just an anomaly!!
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Old 08-16-03, 05:02 PM
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You might try running a lower pressure in the tires... I've been getting the newletter from roadbikerider.com... they guy over there was suggesting that yer rear wheel should be about 105 PSI, and your fron around 95... as long as you are not too heavy, it should be fine... I'm about 170, and roll with about 110 in the back, and 100 in the front.. smooth ride... good rolliong resistance.. no adverse effects that I can tell so far

JEff
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Old 08-16-03, 05:19 PM
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I'm using the Bontrager tube, 120psi and I weigh around 188. I've actually pumped the tire up to 130 with no blow out.
Not sure what's happening with your tubes????
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Old 08-16-03, 05:37 PM
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I was having a problem with blow outs on my tubes. I was using the Performance ones at 115-120 psi. My bike came with Specialized tubes and blew both tubes in 2 days I pumped them to around 115 psi. I also use the Specialized Armadillos, but have since switched to the Michelin tubes and it's all good 120 psi with no problems
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Old 08-16-03, 09:46 PM
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I don't know what you guys are doing wrong! I weigh 240, run fortezza tires at 150 in the rear and 120 in the front. I have VEVER had a tube to blow or tire to just blow! Bontrager select wheel set BTW. This is just weird!
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Old 08-16-03, 10:59 PM
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Have you checked your rimstrips (if you need them) and made sure there are no spokes poking through?
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Old 08-17-03, 02:12 AM
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Are you positive a little bit of the tube wasn't left pinched under the bead of the tyre when you installed it?

The tube will hold pressure initially, usually generating an 'egg' at the pinched zone, before either puncturing the tube, or very commonly blowing the tyre off the rim at that point and blowing a hole in the tube in the process...yes, I did it several times many years ago when I was pretty green.

It is most likely to happen with tyres which are tight/difficult to get on the rim, and hence more likely to wedge the tube under the bead, instead of tucked up inside the casing where it's supposed to be.

BTW: most club riders I know run 120psi front and rear...that's what Contis are rated for commonly...I also have consistently run 120psi on Michelins rated to only 110psi and never had any distortion or failure problems(not that I'm recommending that)
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Old 08-17-03, 08:32 AM
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My lord-you're pumping Armadillos to 120 psi? You must love a hard ride. At 120 psi, those things have to be just a tad softer than a solid tire.
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Old 08-17-03, 10:57 AM
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Originally posted by Dave Stohler
My lord-you're pumping Armadillos to 120 psi? You must love a hard ride. At 120 psi, those things have to be just a tad softer than a solid tire.
I pump mine to 120 and my ride is just fine on my Lemond BA. I can tell no difference between rides for Conti Ultra 2000's, Conti GP 3000's and the Specialized ARmadillo (all at 120 psi). However, both Conti's are a bit faster.

I can tell a great difference when I had the 700x32's or thereabouts on - much slower.
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Old 08-17-03, 12:02 PM
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This is an installation problem or a rim problem. Blowouts as described are a result of imprpoper insallation which can be an improperly seated tire on the rim or a 'pinched tube' which in turn results in poorly seated tire. If your rims are 'spread out' meaning they are wider at top edge of the breaking surface versus the lower edge you'll have an increased incidence of blowouts. 'Spread' rims are rare and usually occur on older silver colored rims not the dark colored anodized rims. Debis in your tires and bad rimstrips do lead to blowouts as described. You will tend to have slow leaks or a quick leakdown.

What kind of rims do you have? Are they hook bead rims? Are your tires folding? If they are there is a higher incidence of blowouts.
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Old 08-17-03, 03:54 PM
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I think they are ALexis rims, sounds right anyway. As far as I know there is nothing in the rim. Ran my fingers around it a couple times looking for sharp edges. I guess it could have been pinched, by the tire. I don't think that was the problem ,but coulda been. I had no trouble getting the tires on. As for the 115 on the armadillos, it was a very nice ride today.
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Old 08-18-03, 03:14 AM
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With 5 bikes, I was tired of pumping up the tires every few days. So I bought a small table model air compressor at Lowes for $55. The best thing I ever did. After you use a compressor a while, you develop a feel for how much air you're putting in, so there's little danger of over-inflating. I run my Michelin Axial Carbon Pros at 110 pounds, which is close to the maximum. This seems to be about right. I can inflate a tire from 80 pounds to 110 pounds in less than 30 seconds. One thing -- don't leave your bike in the sun on a hot day. This can get your tire pressure up over a relatively short peiod of time. I also use the compressor for car tires and blowing dust off my bike and my workbench.
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