Speaker 1: Welcome to Brainstuff from house stuffworks dot com where smart happens. Hi.
Speaker 1: I'm Marshall Brain with today's question, why don't they use
Speaker 1: normal air when they pump up race car tires? Many
Speaker 1: race car teams use nitrogen instead of air in their
Speaker 1: tires because nitrogen has a much more consistent rate of
Speaker 1: expansion and contraction compared to the normal air that we breathe. Often,
Speaker 1: a half pound of pressure will radically affect the traction
Speaker 1: and handling of a tire. With track entire temperatures varying
Speaker 1: over the duration of a race, the consistency of nitrogen
Speaker 1: is needed so that the team and the driver can
Speaker 1: maintain their sanity. Nitrogen pressure is more consistent than normal
Speaker 1: air pressure because air typically contains varying amounts of moisture
Speaker 1: due to changes in the relative humidity on race day.
Speaker 1: Water in the air causes that air to be inconsistent
Speaker 1: in its rate of expansion and contraction. So a humid
Speaker 1: race in the southeast United States or a dry race
Speaker 1: in the desert western United States could make for unpredictable
Speaker 1: tire pressures as the tires heat up and cool down
Speaker 1: during the race. If you use dry nitrogen, which contains
Speaker 1: no humidity. You don't have to worry about these inconsistencies.
Speaker 1: Nitrogen is also used in the high pressure tires of
Speaker 1: large and small aircraft. It turns out that many tire
Speaker 1: shops will now sell you nitrogen filling for your tires
Speaker 1: if you're willing to pay extra for it. Is this
Speaker 1: a good idea? Chances are, in your normal day to
Speaker 1: day driving, a little bit of tire pressure change isn't
Speaker 1: going to make that much difference to you, if any
Speaker 1: at all. And the other ideas that a tire shop
Speaker 1: will use to try to sell you the nitrogen usually
Speaker 1: are red herrings. They'll talk about things like rust your
Speaker 1: inner rims, or attacks by oxygen atoms on the inner
Speaker 1: part of the rubber of the tire, all kinds of stuff.
Speaker 1: Almost all of this falls into the category of urban legend.
Speaker 1: But if you want to pay extra for dry night
Speaker 1: virgenior tires, it certainly isn't gonna hurt anything. For more
Speaker 1: on this and thousands of other topics, doesn't how stuff
Speaker 1: works dot Com, and don't forget to check out the
Speaker 1: brain stuff blog on the how stuff works dot Com
Speaker 1: home page. You can also follow brain stuff on Facebook
Speaker 1: or Twitter. At brain Stuff hs W