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The puncture

This is on the outside of the tube. There is a series of small dots marks about 1-2mm apart, and one of them has turned into a puncture.

I've felt around the inside of the wheel, and the inside of the rim. Everything feels normal.

I thought maybe the inner tube had turned, and the spoke had poked through, but the marks seem too close together to be caused by the spikes.

Anyone got any ideas? I'm wondering if its safe to just put another tube in?

  • My guess is what Argenti said in his answer, could also have been a rough tire lever if you slid one during install. Second guess would be it got pinched between the bead seat and the tire. – Nate W Aug 20 '18 at 19:53
  • Now the old-school technique is to patch the tube, and reinstall it so the valve stem and tyre label align. That way if damage happens again you can measure around from the valve stem and find a 50mm area of tyre/wheel rim to inspect closely, rather than having to eyeball the whole tyre and rim. – Criggie Aug 21 '18 at 9:18
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As the holes appear to be on the raised ribs of the tube wall, it seems something pointed was scraped over the tube.

I'm guessing the damage was done before the tube was installed. Tubes cant move around in the tire, and a tire really cannot move on the rim either.

Update: perhaps there might have been a small sharp object caught between tube and tire during tube installation, that migrated along the tube causing the scratch mark.

In any case inspect the inside of the tire very carefully, both visually with a good bright light and tactually by running you fingers over the inner surface. Small sharp foreign objects can be hard to detect if they are just poking out of the rubber surface.

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  • The dots seem a bit too evenly spaced to have been caused by a migrating object. To me it looks like something that happened at the factory. – Carel Aug 20 '18 at 20:24
  • @carel There appear to be slight raised ribs on the tube wall, the cuts are in top of those ribs, that's why they are evenly spaced. – Argenti Apparatus Aug 20 '18 at 20:26
  • @ArgentiApparatus thanks! I double checked the tire and it seemed fine. – jkh Aug 20 '18 at 21:13

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