It’s a small oversight with huge consequences: driving on tyres that aren’t properly inflated. According to a recent report by Firestone Complete Auto Care, underinflated tyres cost American drivers a staggering $18.6 billion a year just in extra fuel alone. That’s money literally leaking out of your wallet because your car’s tyres are carrying less air than they should.
How does it happen? When tyre pressure drops even slightly, the tyre’s contact patch with the road, the “footprint”, increases. This means more rolling resistance, forcing your engine to work harder, guzzling more fuel to keep your vehicle moving. Studies suggest each PSI (pound per square inch) drop in pressure can increase fuel consumption by 0.2% to as much as 0.5%, depending on who's measuring. For just a 5 PSI underinflation, you could see anywhere between a 1% to 2.5% spike in fuel usage.
But the cost doesn’t stop at your gas bill. Underinflated tyres wear out faster, up to 25-50% shorter lifespan depending on severity necessitating earlier replacements that add to your expenses. They also raise safety risks; more heat builds up in tyres, increasing the likelihood of blowouts or tread separation. Worse still, they elevate harmful carbon emissions, undermining environmental goals even as so many drivers turn to hybrids and EVs.
Data suggests about 42% of vehicles have underinflated tyres, with the average pressure 13 PSI below manufacturers’ recommendations a huge disconnect. Geographically, places like Washington D.C. and California report over half their vehicles running on low pressure tyres. Sports cars and minivans top the list for neglect.
The good news?
The fix is dead simple: regular pressure checks and top-ups. Many service stations offer free inspections, and keeping tyres at the correct pressure can save you hundreds per year and add thousands of miles to tyre life.