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Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

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Old 09-24-11, 06:44 PM   #1
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Time to change my tires?

Hi all,

I recently got my third flat in about a year on my rear wheel. I've patched the other two and decided to get a new tube for the third (left my patch kit at home), but that went flat while I put air in it. I got a replacement and was told it could either be something embedded in the tire or the rim tape.

I've looked at the old tube and none of the punctures are in the rim area. They're all small holes (think pin ******) on the outside so it means something's hitting and getting embedded into the tire. I checked the tire a few times and there appears to be nothing embedded in after checking by hand.

A check of old threads said it could just be a sticker. What puzzles me is the presence of the weird slash marks on the tire. It's like diagonal slashes that appear every so often on the tire itself. I noticed them around the time of the first flat; I thought they were there because I briefly rode the bike with a flat to get home.

Here's the thing though. I ride a 2009 Rockhopper that I bought in 2010, which, if my sources are right, means they're three year old tires (delivered to shops in 2008). I've since put about 1000 miles and God knows how many by prospective owners; should I start to get new tires? I do mostly city riding in a relatively rural town. Either way, I'm going to keep the rim tape on.

TL;DR: I'm getting a lot of fast flats the size of pinholes. Are they related to my rear tire being worn or am I just unlucky/a bad home mechanic? They seem to happen near when I park outside a certain area under a tree.

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Old 09-24-11, 06:55 PM   #2
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I think that what you're seeing is the casing through the wall. Casings have 2 bias plies running at 45° as you see on the side. But tires aren't woven rather each ply consists of strands all running in the same direction and held with glue. These are very delicate, and can come apart when handled, so they weave a cross thread at intervals (not on tubulars) to hold the ply intact during the tire molding process. That cross woven thread is what you're seeing, as the gum cover breaks down with age.

In any case, worn tires don't cause flats, except as the tread layer gets thinner and easier to cut. Flats depend on how much and where you ride. I commute through some rough areas so glass cuts are common. I've gone a year between flats and had three in a month, it's purely random.
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Old 09-24-11, 07:29 PM   #3
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Originally Posted by graytotoro View Post
I've since put about 1000 miles...should I start to get new tires? I do mostly city riding in a relatively rural town.
My opinion is yes, you should get new tires. Not because the old ones are shot, but simply because knobby MTB tires are no fun on pavement. They're slow, noisy, and they corner like crap. Since you suffer frequent flats you could get tires with a flat protection layer. Get some slicks, with a width anywhere from 1.4"-1.75" for much improved performance.

Or a bike more suited to road riding, like a hybrid commuter or road bike.
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Old 09-24-11, 07:55 PM   #4
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Something that really helps is to get in the habit of putting the printed name badge of the tire's sidewall at the valve stem. If it's a long name like "Specialized" then put the "S" right at the stem. Then when you have to change a flat carefully remove the tube so you maintain the orientation then inflate it and find the hole. You can then put the tube up to the tire and locate where the glass, wire, thorn pushed through to cause the puncture. Carefully flex and check any marks on the inside of the tire to see if the wire, glass, thorn is still in the tire and ready to push through the tube again.

In any event only 3 flats in 1000 miles is better than average. These tires aren't thick like car and truck tires and they don't have steel belts. So the number of flats you've gotten would be seen by some as a really low number.
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Old 09-25-11, 06:21 AM   #5
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I agree with 2 of the above posters...

1 .. three flats in 1000 miles is not bad.

2... If all you ride is pavement, Replace those knobbies with some street friendly tires. You'll see an immediate improvement in performance.
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