Understanding why tires lose air

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Updated May 23, 2022
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[This article was originally published in 2017 by Trucks, Parts, Service. It has been updated to include more timely information.]

Pressure Systems International’s (PSI) Commercial Fleet Tire Digest offers insights into tire health, including reasons for decreased air in heavy-duty truck tires.

Volume 11, Issue 6 of the digest addresses why tires lose their inflation, as well as tire inflation solutions. In it, PSI writes, “There are really only four reasons why commercial truck tires lose air: osmosis, leaking valve stems/cores, slow leaking punctures and impact breaks.”

“Tires are similar to a balloon. You inflate a balloon and it may stay inflated for several hours, a day or sometimes even a couple of days. The osmosis rate depends on the gauge of the balloon material plus the actual materials used to manufacture the balloon. The osmosis rate also changes depending on the ambient temperature. An inexpensive balloon will always lose air more rapidly compared to the more expensive balloon,” says PSI Marketing Manager Craig Smith.

PSI says commercial truck tires typically lose 1-3 psi per month just sitting, and that their osmosis rate increases by “about 60 percent when the tire is running at 65 mph resulting in actual loss of up to 5 psi per month.”

For more information from PSI on osmosis and the other air loss reasons, as well as inflation maintenance options and solutions, go to its Tire Digest archive.


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