This season only started getting a lot of flats in my back tire (riding the same Trek 4300 mountain bike for past 6 years and never had this issue). In last 7 days had 3 flats - put new tube yesterday and had a flat today again! Using Lyzene pump to inflate to 40 psi. Inspected the tire and there is no evidence of any protrusions. The puncture in the tube is on the inside - a tiny slit. Inspected the rim as well and no evident sharps there - I have a double wall back wheel.Thinking maybe the tire (original since new) is worn out and is causing this problem. Appreciate feedback. Cheers!

  • Where precisely is the puncture, and how big (and what orientation) is the "slit"? And what do you have for a rim strip? May 8, 2015 at 2:55
  • All these questions and can you put some pictures of the tyre. Despite all of this, these things have a lifetime, and even if the thread ok I would recommend you change both the tyre and the rim strip. Let's face: these have served you well for 6 years, they deserve a rest. Let's hope the new ones do the same :)
    – super
    May 8, 2015 at 4:12
  • 2
    "Time for new tires" sounds good to me too, especially since the originals, while fine, were probably not top-drawer.
    – D.Salo
    May 8, 2015 at 14:32
  • 1
    Six year old tire? I'd say it's time for a new one.
    – onnoweb
    May 8, 2015 at 22:54
  • 1
    Thanks for all the responses. As it turns out the rim strip was the issue. It was made out of either plastic or fiberglass and upon closer inspection there were numerous rough areas that were making these tiny slits. Mechanic in my local bike shop told me that this is rare to occur. In any case I replaced the rim strip with rubber one and so far so good.
    – MiniMatt
    May 9, 2015 at 18:50


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