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Often, mountain bike racers are concerned with the optimal tire pressure to run to decrease rolling resistance or to improve traction on particular courses. But, what is the optimal pressure to avoid slits and punctures?


My recent experience at a race got me wondering about tire puncture theory. I couldn’t find anything online, so I sent the following note to technical guru Lennard Zinn:


Hey Lennard ~

Hope this note findsyou doing great.

I’m having a debate with myself – and others – about mountain bike tire pressure. Not regarding speed and power output – but puncture resistance. Over the weekend I did a race at Pueblo Reservoir, the Voodoo Fire. Rolling through a benign section of trail (non-technical, relatively flat, no big obstacles) I kicked up a piece of shale and it sliced the sidewall of my tire – near the tread.

Though I think it was simply bad luck the way I hit the piece of shale – does tire pressure make adifference one way or the other? Using a balloon and pin theory – if I poke a fully inflated balloon with a pin, it pops almost immediately. If I poke a half-inflated balloon with the pin, the balloon gives quite a bit before failure.One argument is that I should keep running my low tire pressure. Another theory is that more air in the tire may have deflected the shale not allowing it to sink into and slice my sidewall.

So, when running tires on a shale and rocky course do I run more air than normal, less air or run “normal” pressure. (“Normal” being what I would run for a rocky course, sans patches of shale.)

Also, is there any scientific evidence anywhere on this subject (that I couldn’t find)?

In advance, thanks for the answer/theory.




I’ll let you know what Lennard has to say. In the meantime, what do you think? Higher pressure or lower pressure? Let me know your opinion on my Facebook page.

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