So, because I do ultra-light touring I bought new puncture resistant tires for my road bike (Continental Grand Prix 4-Season, 28c), I installed them and after two minutes I had a puncture. First I thought I had punctured the tube when mounting the tires, but then I looked and not one, but TWO pieces of glass had gone through the tire. Is this just extremely unlucky or are these tires worthless?

  • 2
    Did you ride through glass to test your new tyres? Or was the glass already in the tyre when you installed it ?
    – Criggie
    Commented Jun 28, 2016 at 20:12
  • 1
    Why/How exactly would you get new tires with glass in them already?
    – Batman
    Commented Jun 28, 2016 at 22:21
  • Also make sure you're inflating your new tires to the pressure recommended on the tires' sidewall; it may be different from the recommended pressure on your old ones Commented Jun 28, 2016 at 23:22
  • Puncture resistant tires are like IronMan. The suit is pretty beefy, but eventually things get through and it's a mess. Tubeless tires and sealant are like the Hulk, it doesn't really matter what happens because they will likely recover on their own. Commented Jun 29, 2016 at 0:27
  • Se also Broken glass on the bicycle path, what to do?
    – andy256
    Commented Jun 29, 2016 at 0:42

1 Answer 1


While we don't do product reviews, note that puncture resistant doesn't mean puncture proof -- with any air based system, you're going to run the risk of cutting the tire and tube and getting a flat. Some tires are better than others in terms of puncture protection, using things like kevlar belts. The tires you bought trade off for some more the weight and handling performance versus durability to road hazards (by fitting a kevlar belt rather than whatever lighter thing they put in there) so that you have less protection from road hazards than say, a Schwalbe Marathon Plus.

Don't ride through glass and in general avoid road hazards is the best thing to do.

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