A few missing pounds of pressure sounds trivial. The data says otherwise — in wasted fuel, in the life of tires you already paid for, and in the odds of a crash. Here's exactly what the numbers are, and where they come from.
Underinflated tires can cut gas mileage by up to 3% — about 0.2% for every 1 PSI low across all four.
Tires underinflated by more than 25% are three times more likely to be in a tire-related crash.
In 2024, 511 people died in tire-related crashes in the U.S. — yet only 19% of drivers keep their tires properly inflated.3
We'd rather show our work than throw a scary number at you. Set the numbers to your car and watch every line recompute — using only the DOE and NHTSA figures cited below.
The worksheet prices the pressure deficit set above, held year-round, against a 35 PSI placard pressure and a 50,000-mile tire set. Tires drift about 1 PSI a month: without service, neglected cars average 5–10 PSI low; with quarterly visits you average 1–2. The default is that difference — what the service actually recovers, not neglect versus perfection. It counts only fuel and tread; the safety and time you carry on top of that are real but deliberately left out of the number.
The calculator prices gas and rubber. It can't price the rest.
NHTSA identifies underinflation as a leading cause of tire failure, and vehicles running tires 25% or more below spec are about three times more likely to be in a tire-related crash. Even the lucky version — the one that ends on the shoulder instead of in a lane — means a tow, a roadside tire at markup, possible rim or sensor damage, and half a day gone.
On most all-wheel-drive vehicles, tread depth has to match across all four wheels. One tire destroyed early by underinflation on a half-worn set can mean replacing all four. One neglected tire, a four-tire invoice.
Doing this right yourself means a dozen stops a year at air pumps that are broken half the time, checking pressure cold, and re-checking every time Bay Area weather swings. We do it right, at your curb, on schedule.
Rubber is porous — tires leak air naturally even with no puncture. Consumer Reports measured ~3.5 PSI lost over a year at rest.4
Pressure drops about 1 PSI for every 10°F the air cools. A Bay Area cold snap can trip your dashboard light overnight.
Your TPMS warning isn't required to trigger until a tire is 25% low2 — deep into the range where fuel and wear are already bleeding.
Government and independent figures accessed 2026. Dollar estimates are AirSure's own, derived from these sources.