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Old 04-20-07, 11:27 PM   #1
urbanknight
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Is this tire safe?

It has less than 1000 miles on it, but it was a discontinued item (so I don't know how long it was sitting on the shelf) and has been developing these cracks along the shoulders for a while, and now they're covering more than half of the circumfrance. The front tire isn't as bad, but it has tiny cracks too. Is this thing going to fall apart while cornering if I keep riding them?

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Old 04-21-07, 01:25 AM   #2
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"Cracks in the tread are harmless. Small punctures in the tire such as are typically caused by nails, tacks, thorns or glas slivers are also harmless to the tire, since the tire doesn't need to be air-tight."

-From http://www.sheldonbrown.com/tires.html
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Old 04-21-07, 01:25 AM   #3
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Notice the cracks are in the sidewall, not the tread. If it ws just one crack I might ride them a while longer but no, it is a series of cracks all the way around. Please replace both of them. A clear case of bad product to me. I bet the sidewall blows out first.
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Old 04-21-07, 07:35 AM   #4
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I would replace it, but if all you do is ride the bike path at 10 mph or less, it could be ok until you wear it out. Would you trust this tire at 30 mph on a steep descent? I hope not! Don
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Old 04-21-07, 08:07 AM   #5
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Unless i'm mis-reading the picture, the cracks are in teh green rubber, not in the sidewall. When you turn the tire inside out in that area, do you see damage to the casing?
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Old 04-21-07, 08:08 AM   #6
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Quote:
Originally Posted by robo
Unless i'm mis-reading the picture, the cracks are in teh green rubber, not in the sidewall. When you turn the tire inside out in that area, do you see damage to the casing?
Good idea, I'll check that.

I'm not keen on bike tire construction, but on car tires that's called the shoulder, which is between the tread and the sidewall. On a car, that's a no-no to patch (thread only) but I don't know how crucial it is on a bike. I imagine crucial because the bike leans a lot.
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Old 04-21-07, 08:27 AM   #7
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Quote:
Originally Posted by urbanknight
Good idea, I'll check that.

I'm not keen on bike tire construction, but on car tires that's called the shoulder, which is between the tread and the sidewall. On a car, that's a no-no to patch (thread only) but I don't know how crucial it is on a bike. I imagine crucial because the bike leans a lot.

I don't know much about car tires, but i suspect bike and car tires are constructed differently, since car tires are never meant to lean, while bike tires are. So the 'shoulders' of a bike tire are definitely still part of the tread, while on a car they may be more like a bike tire's sidewall.
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Old 04-21-07, 09:08 AM   #8
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I had similar cracks in a tyre sidewall. I retired that one when I got new tyres but I'm keeping it around...

My theory is that these cracks are not an issue as the stress (pressure) is handled by the casing (threads inside) and not the rubber.
It does show that the rubber is aging so grip may not be as good as new.
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Old 04-21-07, 05:32 PM   #9
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I checked the casing and it looks fine on the inside, but just because I already had one wheel mishap recently, I will probably replace them anyway. I wasn't too happy with them in the first place, and am now pretty confident that I trust Continental for clinchers and Vittoria for tubulars.
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