The Autumn Morning Surprise: Gay-Lussac’s Law in Action
Every October, as overnight temperatures across New Brunswick drop from 15°C down to near freezing, thousands of drivers wake up to a glowing yellow horseshoe icon with an exclamation point on their dashboard. No, you probably do not have a nail in your tire—it is simple physics.
According to Gay-Lussac’s Law, gas pressure in a fixed volume decreases in direct proportion to temperature drops. A tire set to 35 PSI in August can easily drop to 28 PSI on a brisk October morning, triggering your vehicle’s Tire Pressure Monitoring System (TPMS).
The Hidden Cost of Under-Inflation
Driving even 4 to 6 PSI below manufacturer recommendation flexes the tire sidewalls excessively, generating heat and wearing out the outer shoulder treads within a single season.
Additionally, under-inflated tires increase rolling drag, which forces your engine or EV battery to work harder, reducing fuel economy by up to 5%.
