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Old 03-31-12, 08:42 PM   #1
Myosmith
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Tire and tube questions

1) I've got a Specialized All Condition tire that picked up a piece of glass today. I plucked the glass bit and all appeared OK for about 20 miles then the tire went flat. I pulled the tube and found a pinhole in the tred side. I went back to the tire and using the tube for reference hunted for any sharp objects. I found a small nick in the outside of the tire and a pinhole in the inside. I felt inside and out carefully, pushed on the spot from the outside while feeling the inside, flexed the tire and even tried a cotton ball, but could find nothing sharp. I put in a new tube and put on another 20 miles then had another flat. I haven't fixed it yet, but I suspect that I may have missed a tiny bit of glass buried somewhere in that hole. I'll know for sure when I pull the tube and line up the leak with the spot on the tire. The question is, assuming it is a bit of glass still buried in the rubber of the tire and not just unfortunate coincidence of having two flats on the same tire within 40 miles, is there a good way to remove that/those bits when you can't feel them from the outside? Could something like a sewing needle be used to probe the hole? Any better ideas?

2) Related to first question; I now have two very slightly used tubes, one of which has already been patched. Should I keep the patched tubes as backup, or would you trust them for long term used in a tire that runs 120 psi?
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Old 03-31-12, 09:27 PM   #2
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Try turning the tire inside-out when you search for the offending sharp object. This will place the inside surface of the tire under tension which may help to open up any tiny holes where a glass shard or whatever may be hiding. Try the cotton ball again while doing this.
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Old 03-31-12, 09:31 PM   #3
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Occasionally (it's happened to me twice in 30 years) a slice in the tire is just big enough to let the tube bulge through, but not enough to let it pop. You'll fix the first flat, remove the flat-maker, patch the tube, and go on your merry way. 20 miles later, the tube will wear through because it's hitting the ground. The only solution is a tire boot or, more permanently, a tire boot.
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Old 03-31-12, 09:34 PM   #4
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I prefer to use the patched tubes first, and keep the new ones as spares. If I patch a tube that is orherwise in decent shape (not old and dried out), then I'll trust is as a spare. This is partly to use up old stuff first, and not end up with a bunch of old dried marginal tubes. The other part is sort of a superstition. I figure that spares should be the most reliable you have, since once you use them, you're without backup.

As for finding and removing the small shards that may be embedded in the tread. I run the back of a finger down the inside of the tire in the suspect area, and also roll the tread between my fingers spreading all the nicks open to see what's lurking in there. I've never used anything special to flick out those small shards, which I can usually get out with a fingernail. Sometimes, I'll use the smallest hex key, or the screwdriver blade of my folding hex tool (the only tool I carry on my road bike, other than tire levers)
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Old 04-01-12, 06:13 AM   #5
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When I have had 2 flats in a short period of time on the same wheel, most of the time the second was due to something that I did wrong while changing the first. Pinching a bit of tube under the tire bead and insufficient air pressure are two biggies.

Once I had a tire on my beater bike with a piece of something in it that I never could find and, trust me, I did all of the things the other posters have mentioned. After searching several times I eventually cut the valve stem out of an old inner tube to use as a tire liner and ultimately replaced the tire. That's only happened once in all my years of bicycling.

I patch and reuse tubes all the time and have for decades. I've found them to be as reliable as new tubes regardless of air pressure. I don't do anything fancy when I patch them either - just follow the directions on the patch kit box. I used to save up 4 or 5 to do on a rainy Saturday.
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Old 04-01-12, 06:37 AM   #6
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Myosmith, First is to determine where the second puncture is. I've had second flats because I was in a hurry repairing the first and screwed up and an old patch kit's glue wasn't really glue anymore (still my fault, really).

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Old 04-01-12, 07:19 AM   #7
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Checking out a flatted tire is a matter of methodically and meticulously inspecting that tire inside and out. There is so much broken glass on roadways I've adopted the practice of inspecting my tires for glass shards about once a week. I let the air out and pinch the rubber between thumb and forefinger to open up cuts. I almost always find at least one glass shard that I then carefully dig out with, say, a tiny screw driver or dental pick. I suspect I've avoided numerous flats because of this.
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Old 04-01-12, 08:38 AM   #8
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Fixed the flat this AM. Turned out it was a second puncture several inches from the first. After I inspected both the original puncture and the new one, I could find no foreign objects, but there was a tiny nub of rubber raised on the inside of the second puncture that was rather pointed. I sanded it down a bit then applied a small inner tube patch as an experiment. I've often wondered if the larger patches could be used as a semi-permanent boot. The patch took and leaves a smooth surface inside the tire. Now if my inner tube patches hold up (both passed the bubble test) I'll be set. My wife is picking up a couple of new tubes at the LBS today so I can keep them on hand.
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Old 04-01-12, 11:10 AM   #9
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That's what I was going to suggest, where the flats are/were occurring at possible inner tire damage, one could clean up the spot of any excess rubber and materials that might be agitating the tube to failure. And use duct tape or something similar to line the inside of the tire. I had a 100 psi tire with a glass cut that I was able to get a few years and a lot more miles repairing it that way. Your patch solution sounds like it's tougher & more durable than tape, but like the other post indicated, as long as the inner tube doesn't pinch or go thru the hole in the tire ? Then again, what are the chances you're going to puncture thru wt the exact same spot on the tire ?
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Old 04-01-12, 11:16 AM   #10
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Quote:
Originally Posted by Jeff Wills View Post
Occasionally (it's happened to me twice in 30 years) a slice in the tire is just big enough to let the tube bulge through, but not enough to let it pop. You'll fix the first flat, remove the flat-maker, patch the tube, and go on your merry way. 20 miles later, the tube will wear through because it's hitting the ground. The only solution is a tire boot or, more permanently, a tire boot.
Agree. I've had this happen.

Quote:
Originally Posted by Myosmith View Post
Fixed the flat this AM. Turned out it was a second puncture several inches from the first. After I inspected both the original puncture and the new one, I could find no foreign objects, but there was a tiny nub of rubber raised on the inside of the second puncture that was rather pointed. I sanded it down a bit then applied a small inner tube patch as an experiment. I've often wondered if the larger patches could be used as a semi-permanent boot. The patch took and leaves a smooth surface inside the tire. Now if my inner tube patches hold up (both passed the bubble test) I'll be set. My wife is picking up a couple of new tubes at the LBS today so I can keep them on hand.
I've "booted" a tire this way (with a glue patch) with success. I did, however, move this tire to the week-day, after-work ride bike.
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Old 04-01-12, 01:05 PM   #11
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for the stubborn flats which are mostly from wires off of steel belted tires, i run a linty rag or well used blue shop towel along the inside. the sharp point catches the lint and you win
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