ASK THE BMXPerts: HIGH PRESSURE OR LOW PRESSURE
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I dont understand why sometimes you guys will say a high pressure tire is good, but then other times you say that a tire is good because you can run it soft. What is the difference?

There are two forces at play here so we will break them down separately. First, pressure rating. Tires are rated by their casing and to put it very simply, a tire that is rated for say 40-50psi, has a very thin casing or structure, not at all worthy of real riding. Most affordable BMX tires are rated up to 65psi which means a stronger casing, more resistance to pinch flats and less tire displacement on hard landings. Now take a high pressure tire rated up to 110psi and you generally have a lighter weight tire because heavier rubber has been replaced with more threads in the casing, a tire that can handle more pressure and a tire will displace less on landings.

Now for the second issue, actual pressure. Ramp riders like to run more pressure in their tires so the tires wont mush out when they push though transition, while street riders run lower pressure to soften landings. So why would they both run the same high pressure tire? Displacement. Think of a tire like a balloon. A tire with a low pressure rating will react like squeezing a balloon, compress one spot and it will just inflate more somewhere else. Now wrap that balloon tightly in a tee shirt and squeeze it, it will still try and bubble up somewhere else, but the shirt restricts it from doing so as dramatically. The shirt has the same effect as a high pressure tire casing, meaning you can still run a lower pressure on the streets, which we like, but the high pressure casing keeps the tire from ballooning out elsewhere and saves you from a pinch flat and a long walk home.

So remember, a high pressure casing can hold its form up to a set pressure, meaning you could ride vert at 110psi and the tire wont displace when you pump through transition, or you could run 65psi on the street and a the tire will only compress about halfway, where a lesser tire would pinch flat.


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Send your questions to: askthebmxperts@bmxplusmag.com


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