Is my old tire safe?
09-04-09 | 01:11 AM
#1
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Is my old tire safe?
I have a 20 year old bike that was recently fixed up. The tire on the rear wheel was on the bike when I found it, and it looks pretty worn out. The sidewalls have little cracks and fissures running along them.
Is this tire still usable and safe, or do I need a new one?
Is this tire still usable and safe, or do I need a new one?
09-04-09 | 01:19 AM
#2
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"Safe" isn't a calibrated measurement. A 20 year old tire will have less friction than a newer one and is more likely to rupture under pressure.
With that said, the probability of even an old tire spontaneously self-destructing while JRA is quite slim.
I'd say that it's probably still usable, but not as safe as a new tire would be. For what they cost, and for the trouble they can save you - get a new one.
If you're set on using it - try over inflating it a while, see if it holds up. If it does, lower the pressure and ride.
With that said, the probability of even an old tire spontaneously self-destructing while JRA is quite slim.
I'd say that it's probably still usable, but not as safe as a new tire would be. For what they cost, and for the trouble they can save you - get a new one.
If you're set on using it - try over inflating it a while, see if it holds up. If it does, lower the pressure and ride.
09-04-09 | 01:54 AM
#3
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Hard to say. If the rim bead, casing and inner rubber portion/lining of the tire is intact and not cracked/frayed, then it "could" be ridden with a certain amount of confidence. That being said, a pair of decent new tires, tubes, and rim tape or rim strips are relatively inexpensive to purchase and you'll won't have to question the integrity or reliability of your tires or tubes. Total cost should be less than $50.
09-04-09 | 02:03 AM
#4
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Joined: Mar 2002
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From: Helsinki, Finland
Safety hazards with bike tyres are more related to whether the tyre is going to suddenly deflate on a downhill, for example. Worn out thread alone is not an issue like it would be with car tyres. Many bike tyres are slick to begin with. But if there are cracks and fissures in the sidewall, I'd replace it to avoid having it explode during a ride.
--J
--J
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09-04-09 | 04:47 AM
#5
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True, but slick-and-dried-out isn't the same as slick-but-fresh-from the factory. Ever noticed how an old eraser sometimes just skids along the paper w/o engaging?
09-04-09 | 08:24 AM
#6
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From: Southern California
When in doubt, change it out. Tires are way too important to risk your safety, both from a traction and structural perspective. Rubber dries out, elements crack... who knows.
Now if you had old handlebar tape that you wanted to keep, I'd say that's okay to use after 20 years.
Now if you had old handlebar tape that you wanted to keep, I'd say that's okay to use after 20 years.
09-04-09 | 08:34 AM
#7
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From: Zang's Spur, CO
This happened just a few hours after I did a 45mph descent.
It was the *front* tire.
"...you've got to ask yourself one question: Do I feel lucky? Well, do ya, punk?"
09-04-09 | 07:42 PM
#13
My bike's better than me!
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From: Northern Colorado
Bikes: Moots Vamoots, 'Dale T2000, DB Response Comp, '98 G. Fisher HKEK, '89 Panasonic DX-6000, '88 Fisher Montare XT, '83 Nishiki Int'l, '72 MB GR, '75 MB GJ, '77 MB LC, '85 Centurion Ironman, '82 Miyata 710
Originally Posted by TheLateGreatSheldonBrown
"Dry rot" is a fungus that infects cellulose-based materials: wood, paper, cotton and the like.
Sometimes people speak of bicycle tires as if they suffer from dry rot, but this is not generally correct. (The exception would be for cotton-cord tires, but those pretty much disappeared by the mid 1960s, at least as far as clinchers are concerned.)
What people commonly call "dry rot" is a deterioration of the rubber, usually on the sidewalls. This is particularly common with gum wall tires that have been exposed to ozone damage. (A common cause of this is storing a bicycle near a household furnace. The brush-type motors on such furnaces often create sparks, which in turn create ozone.)
This type of damage is ugly, but not structurally significant, as long as the cords (fabric) of the tire are intact.
Generally, if a tire isn't lumpy/misshapen when inflated, and has not had the tread area worn too thin, there is no reason to replace it, no matter how ugly the sidewalls get.
Sometimes people speak of bicycle tires as if they suffer from dry rot, but this is not generally correct. (The exception would be for cotton-cord tires, but those pretty much disappeared by the mid 1960s, at least as far as clinchers are concerned.)
What people commonly call "dry rot" is a deterioration of the rubber, usually on the sidewalls. This is particularly common with gum wall tires that have been exposed to ozone damage. (A common cause of this is storing a bicycle near a household furnace. The brush-type motors on such furnaces often create sparks, which in turn create ozone.)
This type of damage is ugly, but not structurally significant, as long as the cords (fabric) of the tire are intact.
Generally, if a tire isn't lumpy/misshapen when inflated, and has not had the tread area worn too thin, there is no reason to replace it, no matter how ugly the sidewalls get.
09-04-09 | 08:19 PM
#14
Older than dirt
Joined: May 2008
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From: Winchester, VA
Bikes: Too darn many.. latest count is 11
I'll keep it simpler...
If it's going to fail it will do so when you're 10 miles from civilization with a dead cell phone battery. The likelihood of a 20 year old tire putting you in that position is high
If it's going to fail it will do so when you're 10 miles from civilization with a dead cell phone battery. The likelihood of a 20 year old tire putting you in that position is high
