It is common advice that properly inflated tires can improve your fuel economy, but how much of a difference does it actually make? To find out, we examined the impact of tire pressure on gas mileage through a controlled experiment, referencing insights from trusted sources like Tire Rack and Michelin.

Setting Up the Experiment

To conduct a controlled and realistic test, we used a midsize sedan in good mechanical condition and ran two sets of identical driving routes:

• Route: 30 miles of mixed city and highway driving.

• Variables: Same weather conditions, same driver, minimal traffic variation.

• Measurements: MPG calculated through vehicle trip computer and verified by manual fuel refill method.

We conducted the test twice:

1. Under-Inflated Tires: Tires were set at 5 PSI below the manufacturer’s recommended pressure.

2. Properly Inflated Tires: Tires were inflated to the exact pressure recommended by the vehicle manufacturer.

Results

• Under-Inflated Tires: The vehicle averaged 25.1 MPG across the route.

• Properly Inflated Tires: The vehicle averaged 27.6 MPG on the same route.

Conclusion

The vehicle with properly inflated tires achieved approximately 10% better fuel efficiency compared to the under-inflated setup. This real-world result aligns with studies from Tire Rack, which suggest that under-inflation can lower gas mileage by 0.2% for every 1 PSI drop across all four tires. Michelin also emphasizes that maintaining correct tire pressure improves not only fuel economy but also tire lifespan, braking performance, and overall driving safety.

Why Tire Pressure Matters for Fuel Economy

Low tire pressure increases rolling resistance—the force resisting motion when a tire rolls on a surface. Higher rolling resistance forces the engine to work harder, consuming more fuel. Maintaining optimal tire pressure minimizes this resistance, helping you drive more efficiently.

How to Maintain Proper Tire Pressure

• Check Tire Pressure Monthly: Use a reliable tire gauge to measure pressure when tires are cold.

• Follow Manufacturer’s Recommendations: The recommended PSI is usually found inside the driver’s door or in the vehicle’s owner’s manual.

• Inspect Tires Before Long Trips: Especially important before road trips where fuel economy and safety are critical.

Save Even More at the Pump

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Final Takeaway

Keeping your tires properly inflated is a simple yet powerful way to boost your fuel efficiency, improve your vehicle’s performance, and extend tire life. As our experiment shows, this small maintenance habit can have a real impact on your driving costs over time.