8

rip1

How much risk are these tires in or popping? I didn’t even notice till right now.

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  • 5
    I don’t think they’ll pop. But they just don’t seem like good tires and I wouldn’t expect good grip from rubber that degraded. You’ll be fine with easy cruising on asphalt and nice gravel.
    – Paul H
    Jul 29, 2023 at 19:30

3 Answers 3

23

This is old rubber. Depending on the state of the carcass (the fabric within the rubber), it's still perfectly rideable. However, you can expect a slightly increased puncture frequency (small stones/shards may get captured in the cracks and proceed to work their way inward) and/or reduced traction (old rubber loses its compliance degrading the quality of the contact to the road). Very old tires may indeed fail with a bang, but I'd judge this tire to not be that old.

Both effects (puncture frequency and traction) should be relatively minor if money for a new tire is in short supply. Given enough money, I'd replace the tire simply for peace of mind.

Btw, besides being old rubber, this tire has probably been run with too little pressure for a while. Always keep the pressure within the rated range to avoid preliminary cracking.

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  • 5
    This is correct. The rubber doesn't hold the air pressure, it's usually polyester or in some cases cotton cords. Some very fine old tires used silk. If the rubber degrades, the cords are still perfectly fine. The only case to be worried is if the rubber degrades so much the cords become visible. Of course wet traction on old rubber really sucks.
    – juhist
    Jul 29, 2023 at 20:19
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Two main problems with old rubber like this - risk of punctures is increased, as already describe in the answer by @monica, but the other problem is the rubber is now hardened and has less traction, especially in the wet. This means the risk of sliding is increased - less stopping ability and lower cornering ability. Both can increase the chances of a crash.

When you replace them, you will probably be surprised just how much better the new tires are at cornering and stopping, the loss of traction happens slowly, and the rider does not notice it. If it is in your budget to replace, then I would recommend it, otherwise ride more carefully (or slower) than you used to.

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  • +1. Small side note: I've found that often only the top surface of the rubber seems to be degraded. Riding for an hour or so on a safe (non technical and no traffic) gravel path seems to scrub this off and reveal good rubber underneath.
    – Andy P
    Jul 31, 2023 at 8:41
3

The other answers deal with the puncture resistance and the traction.

There is a third failure mode of the old cracky rubber: it wears out impressively quickly. Be prepared to get like 1/10 or 1/20 of the expected mileage before the pattern completely disappears, at least at the center.

In short, riding tires like these can be done safely, but they won't buy you much time anyway.

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