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Today I managed to run over a flat heat board pin, and my tyre got punctured.

I will change my inner tube tomorrow, because it's not that expensive and I find it easier than patching it up.

My question is: Should I be concerned that the outer rubber tyre was damaged? If so, would applying a tyre patch on the interior of the outer rubber tyre do any good? Or would it make things even worse for the new tube? My fear is that the hole means a weak spot in my tyre, and that the tube would break.

Thanks for your help!

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    As long as it is a pin sized nail and not a rail road tie then you should be just fine replacing the tube and still using the tire. Just be sure the pin is not still in the tire ready to flat another tube. – Nate W Jul 19 '16 at 21:47
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    If its just a puncture, learn to patch the tube. Don't be a consumer and spend $4 on a new tube when a patch is about 30c each. I've got one tube working fine with a dozen patches, that would be $48 in new tubes vs $4 in patches. The only things that kill a tube are a big cut, a valve failure, or a hole that is awkward to patch because its near another patch or right by the valve stem. – Criggie Jul 19 '16 at 22:56
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    @Criggie I personally use a new tube, then patch the old tube at my leisure at home, in the dry/warm. As an added bonus, it gives the patch longer to dry/cure. – Aron Jul 20 '16 at 9:35
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    @aron yes - patching on the roadside is no fun. Carry a spare tube (which can be a patched and tested one) and swap them over on the roadside. Then patch at your leisure at home. – Criggie Jul 20 '16 at 20:29
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    Another vote for patching a tube. It costs pennies compared to the $10 bucks for a new tube. Chemically, it is considered a permanent repair as the vulcanizing fluid bonds the patch to the tube. And even the use of rubber cement, while not chemically the same, works just as well in my experience. I routinely ask for flat tubes and patch them. I give them out to people who need them on the road. You can buy patches in bulk. It's the way to go. – user26705 Jul 28 '16 at 20:27
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The size of the puncture really dictates whether a new tire is in order... that being said, if you patch your tube and inflate the tire (the one with the puncture) you want to make sure the tube is not exposed through the puncture hole.

If you need to ride and the tyre is questionable... an old trick is to put a dollar bill or power bar wrapper on the inside of the tire over the puncture hole... then install the tube and inflate. The pressure from the inflated tube will be distributed across the wrapper resulting in an extra barrier keeping the tube from protruding.

Good Luck.

  • At least use a patch of duct tape for this inner reinforcement. – Kaz Jul 19 '16 at 23:01
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If you purely have a puncture by a pin, small nail, or fragment of glass, and the hole in the tire is just a puncture and not a slit, then there is no need to do anything special with the tire -- just put in a fresh (new or repaired) tube and go.

You do need to be concerned if the puncture somehow causes a cut in the tire, with a dimension of more than about 1/4" to 3/8" (maybe 6-10mm), as that can allow the tube to balloon out through the cut, resulting in a blow-out. (The higher the tire pressure, the smaller the cut that can cause this hazard. One needs to be especially wary with high-pressure road tires.)

If there is a sizeable cut in the tire, you need to somehow "boot" it if you are not going to replace the tire. Booting is addressed in this answer.

  • Thanks for your answer. The hole is not that big, only 1 mm small, but I'll boot the tyre too, just to be safe – Andrei Mazareanu Jul 20 '16 at 7:52
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I'd say, there are three degrees of tire damage:

  1. Pointlike damage like your pin can be ignored entirely. The tire will work the same as before the damage.

  2. Cuts large enough for you to bend the rubber away far enought to be able to shine a light through the puncture. Such a tire won't fail immediately if you reuse it, but it may fail sooner than you like due to some small stones working their way into the pre-punched hole, and then proceed to destroy the tube inside.

  3. Cuts large enough that they weaken the inner structure of the tire, allowing the pressure in the tube to push the hole open. Such a tire needs immediate replacement.

Of course, the lines between these three cases are a bit blurry, but I think this is a useful classification.

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