Will Bigger Tires Affect My Gas Mileage?

The Short Answer

Yes, bigger tires generally decrease fuel economy by 1-3% per inch of diameter increase. But the impact depends on several factors.

Why Bigger Tires Use More Gas

• Weight: Larger tires weigh more. Each pound of rotating weight affects acceleration like adding 4-7 lbs of static weight.
• Rolling resistance: Wider tires have more rubber contacting the road, increasing friction.
• Aerodynamics: Wider tires create more aerodynamic drag, especially at highway speeds.
• Gearing: Taller tires effectively lower your gear ratio, making the engine work harder at low RPMs.

Typical Impact

• 1" taller: ~1-2% decrease in MPG
• 2" taller: ~2-4% decrease in MPG
• 3"+ taller: ~4-8% decrease, plus you likely need a regear

Speedometer Error

Bigger tires make your speedometer read slower than actual speed. A tire that's 3% larger in diameter means when your speedo says 60 mph, you're actually going 61.8 mph. This also means your odometer under-reports mileage.

Use our speedometer correction calculator to see the exact difference.

How to Offset the MPG Loss

• Regear: Install a numerically higher gear ratio to restore the effective ratio
• Choose wisely: All-terrain (AT) tires get better mileage than mud-terrain (MT)
• Maintain pressure: Under-inflated tires significantly worsen fuel economy