Tire Impact on Fuel Economy Guide | Rolling Resistance
How tires affect fuel consumption, from NHTSA and fueleconomy.gov: rolling resistance, tire pressure, low rolling resistance tires and maintenance, plus the EU rolling resistance classes.
About This Guide
Tires affect fuel economy mainly through rolling resistance and inflation pressure. This guide collects what NHTSA and fueleconomy.gov say about rolling resistance, low rolling resistance tires, tire pressure and maintenance, and how the EU rolling resistance classes work. Percentages are quoted from those sources or labelled as calculated.
How Tires Affect Fuel Economy
What NHTSA and fueleconomy.gov say about tires and fuel economy.
1. Rolling Resistance (biggest factor)
NHTSA says tires with low rolling resistance have characteristics that reduce energy loss, and estimates that a 10% reduction in tire rolling resistance improves fuel economy by 1 to 2%. NHTSA says these tires commonly have higher inflation pressure and reduced sidewall and tread deflection. The rolling resistance guide goes through the EU label grades, and the rolling force and power calculator turns a coefficient into numbers.
2. Tire Inflation Pressure
fueleconomy.gov says under-inflated tires can lower gas mileage by about 0.2% for every 1 psi drop in the average pressure of all tires, and that keeping tires properly inflated improves gas mileage by 0.6% on average, up to 3% in some cases. NHTSA says properly inflated tires can save as much as 11 cents per gallon and extend the average life of a tire by 4,700 miles. Pressure in kilopascals is converted on the kPa to PSI tire pressure page, and the tire pressure calculator covers the rest.
3. Maintenance
NHTSA says rotation, balance and alignment can help tires last longer. If the vehicle manufacturer recommends rotation, NHTSA says to rotate every 5,000 to 8,000 miles or sooner if uneven wear appears. NHTSA gives no fuel economy figure for these. See the wheel alignment guide and the tire rotation guide for the maintenance side.
Tire Pressure vs. Fuel Economy
fueleconomy.gov figure for under-inflation, with calculated multiples.
| Inflation Level | vs. Spec | MPG Effect | Notes |
|---|---|---|---|
| Average of all four tires 1 psi below spec | −1 psi | about −0.2% | fueleconomy.gov figure |
| Average 2 psi below spec | −2 psi | about −0.4% | Calculated (2 × 0.2%) |
| Average 5 psi below spec | −5 psi | about −1.0% | Calculated (5 × 0.2%) |
| Average 10 psi below spec | −10 psi | about −2.0% | Calculated (10 × 0.2%). Check the tire for damage and the placard pressure. |
Fuel Economy and Tire Type: What the Sources Say
Statements from NHTSA and fueleconomy.gov. We found no official figures by tire category.
| Tire Type | MPG vs. Baseline | EV Range Impact | Notes |
|---|---|---|---|
| Low rolling resistance tires | NHTSA: a 10% cut in rolling resistance is estimated to improve fuel economy by 1 to 2% | NHTSA: extends the range of electric and hybrid vehicles | Keep the load index and speed rating on your placard |
| Properly inflated tires | fueleconomy.gov: 0.6% better on average, up to 3% in some cases | — | Use the placard pressure, not the sidewall maximum |
| All other tire types (summer, all-terrain, mud-terrain, winter) | No official figure found | No official figure found | Compare the maker's data or the EU rolling resistance class |
Sources: NHTSA TireWise and fueleconomy.gov Gas Mileage Tips.
Frequently Asked Questions
How much do tires actually affect fuel economy?
NHTSA estimates that a 10% reduction in tire rolling resistance improves vehicle fuel economy by 1 to 2%, and says low rolling resistance replacement tires improve fuel economy and reduce fuel costs. fueleconomy.gov says keeping tires properly inflated improves gas mileage by 0.6% on average, up to 3% in some cases.
Do bigger, wider tires hurt fuel economy?
We have no official source giving a figure for tire width or size and fuel economy, so this page does not give one. NHTSA says tire design influences rolling resistance among other properties. Compare the rolling resistance class or the maker's data for the specific tires, and keep to sizes your vehicle manufacturer approves.
How often should I check tire pressure for best fuel economy?
NHTSA says to check the pressure of all tires, including the spare, at least once a month when the tires are cold, meaning the car has not been driven for at least three hours. Use the pressure on the Tire and Loading Information Label or in the owner's manual, not the maximum pressure on the sidewall (fueleconomy.gov).
Can wheel alignment affect fuel economy?
NHTSA says a wheel alignment maximizes the life of your tires and prevents the car veering, and that rotation, balance and alignment can help tires last longer. NHTSA does not give a fuel economy figure for alignment.
Are EV tires different from regular tires for fuel economy?
NHTSA says low rolling resistance replacement tires extend the range of electric and hybrid vehicles. We have no official source for a range figure, so this page does not give one. Michelin says tires must meet or exceed the load and speed ratings the vehicle manufacturer specifies.
What do the EU rolling resistance classes mean?
Regulation (EU) 2020/740 grades fuel efficiency from A to E by rolling resistance coefficient. For passenger car (C1) tires, A is 6.5 N/kN or less and E is 10.6 N/kN or more. See the Rolling Resistance Guide for the full table.
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