SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/bike-tire-pressure-pinch-flat

A flat bike tube has two small matching slits side by side. What usually caused it?

A rim pinch: the tube got squeezed between the rim and a bump.

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  1. A thorn stuck in the tread
  2. A leaky valve core
  3. A rim pinch ✔

Why: Double slits usually mean the tube was pinched between the rim and something in the road or trail. More air pressure or wider tires help prevent it.

Huh, didn't know that: Park Tool says a cut at the valve can come from riding with low pressure, so check pressure before rides.

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Why was the bike tired? It was under a lot of pressure.
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References

Answer: A rim pinch. Double slits usually mean the tube was pinched between the rim and something in the road or trail. More air pressure or wider tires help prevent it.

  1. Park Tool: Tire and Tube Removal and Installation www.parktool.com/en-us/blog/repair-help/tire-and-tube-removal-and-installation
    Double slits are commonly the result of a rim pinch. The tube was pinched between the rim and an object in road/trail.
    Checked 2026-10-12.

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