Rolling Resistance Guide: What It Is, What Causes It, and How It Affects Fuel Economy & EV Range
What rolling resistance is, the EU tire label A–E classes from Regulation (EU) 2020/740, and what NHTSA and fueleconomy.gov say about inflation pressure and fuel economy.
Quick answer
Rolling resistance is the force that resists a tire as it rolls. NHTSA estimates that a 10% reduction in tire rolling resistance improves fuel economy by 1 to 2%, and fueleconomy.gov says under-inflated tires can lower gas mileage by about 0.2% for every 1 psi drop in average pressure. In the EU the rolling resistance class (A to E) is on the tire label under Regulation (EU) 2020/740.
Use the companion calculator
Tire Rolling Resistance Calculator
Enter a Crr, vehicle mass and speed to get the calculated rolling force (N) and power.
What rolling resistance actually is
Rolling resistance is the force that resists a tire's motion as it rolls on a surface. The EU label measures it as a coefficient in newtons per kilonewton of load (N/kN) under Annex 6 to UNECE Regulation No 117.
The relationship is F_rr = Crr × W, where F_rr is the rolling resistance force, Crr is the dimensionless coefficient and W is the load on the tire. Double the load and the force doubles (calculated).
Illustration (calculated, not a measured tire): a Crr of 0.010 and a 1,500 kg vehicle give a rolling resistance force of 0.010 × 1,500 × 9.81 ≈ 147 N.
The physics: what drives rolling resistance
The sources below name the tire and operating factors that change rolling resistance and fuel economy.
Tire design
NHTSA
NHTSA says the way tires are designed, such as materials, construction and tread design, influences performance and fuel efficiency, and that tires with low rolling resistance have characteristics that reduce energy loss. Low-rolling-resistance tires commonly include higher inflation pressure and reduced sidewall and tread deflection.
Inflation pressure
NHTSA, fueleconomy.gov
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. NHTSA says properly inflated tires can save as much as 11 cents per gallon.
Load
EU Regulation 2020/740
The EU label measures rolling resistance as a coefficient in newtons per kilonewton of load (N/kN), so the force is the coefficient times the load. A heavier load means a larger rolling resistance force at the same coefficient.
Rolling resistance coefficient limits by EU class
These are the official rolling resistance coefficient limits for each EU fuel efficiency class, in N/kN, from Regulation (EU) 2020/740 Annex I. Divide by 1000 for the dimensionless Crr.
| Class | C1 (passenger car) RRC, N/kN | C2 (light truck) RRC, N/kN | C3 (heavy truck) RRC, N/kN |
|---|---|---|---|
| A | RRC ≤ 6.5 (Crr ≤ 0.0065) | RRC ≤ 5.5 | RRC ≤ 4.0 |
| B | 6.6 to 7.7 | 5.6 to 6.7 | 4.1 to 5.0 |
| C | 7.8 to 9.0 | 6.8 to 8.0 | 5.1 to 6.0 |
| D | 9.1 to 10.5 | 8.1 to 9.0 | 6.1 to 7.0 |
| E | RRC ≥ 10.6 | RRC ≥ 9.1 | RRC ≥ 7.1 |
EU tire label A–E grades decoded
Regulation (EU) 2020/740 applies a tire label with a fuel efficiency (rolling resistance) class and a wet grip class from A to E, plus an external noise class. The two grades are independent, so read both.
Highest fuel efficiency class
C1 (passenger car) tires: RRC of 6.5 N/kN or less.
Second class
C1 tires: RRC of 6.6 to 7.7 N/kN.
Middle class
C1 tires: RRC of 7.8 to 9.0 N/kN.
Fourth class
C1 tires: RRC of 9.1 to 10.5 N/kN.
Lowest fuel efficiency class
C1 tires: RRC of 10.6 N/kN or more.
Always check wet grip grade separately
Rolling resistance (fuel efficiency) and wet grip are graded independently on the EU label, so a tire can have a different class for each. Read both, along with the noise class.
Factors that determine rolling resistance
Factors named by NHTSA, fueleconomy.gov and the EU label regulation. Inflation pressure is one of them; the tire pressure calculator and the kPa to PSI conversion chart help when a placard or gauge uses another unit.
Factor 1
Inflation pressure
Under-inflation lowers gas mileage
Magnitude
fueleconomy.gov: about 0.2% for every 1 psi drop in the average pressure of all tires; keeping tires properly inflated improves gas mileage by 0.6% on average, up to 3% in some cases.
Practical tip
Use the pressure on the sticker in the driver's door jamb or glove box or in your owner's manual, not the maximum pressure printed on the tire sidewall (fueleconomy.gov). NHTSA says to check pressure at least once a month when the tires are cold.
Find your recommended tire pressureFactor 2
Tire design
Materials, construction and tread design
Magnitude
NHTSA says tire design influences durability, wet and dry traction, handling, ride comfort and rolling resistance, and that low-rolling-resistance replacement tires improve fuel economy.
Practical tip
In the EU, the label gives the rolling resistance class A to E. In the US there is no equivalent label on the tire; check the maker's specifications.
Factor 3
Load on the tire
Higher load means a larger rolling resistance force
Magnitude
The rolling resistance force is the rolling resistance coefficient times the load (F = Crr × load), so doubling the load doubles the force (calculated).
Practical tip
Do not exceed the load capacity on the vehicle placard. Michelin says a tire's load rating must always meet or exceed the vehicle manufacturer's value.
Factor 4
Tire maintenance
Rotation, balance and alignment
Magnitude
NHTSA says rotation, balance and alignment can help tires last longer, and that a wheel alignment maximizes tire life and prevents the car veering. NHTSA does not give a rolling resistance figure for them.
Practical tip
Follow your owner's manual for rotation. NHTSA says that if recommended by the vehicle manufacturer, rotate tires every 5,000 to 8,000 miles or sooner if uneven wear appears.
Scrub radius guideThe grip/efficiency/wear tradeoff triangle
What the sources say about how rolling resistance relates to other tire properties.
Fuel efficiency and wet grip are graded separately
Typical compromise
Regulation (EU) 2020/740 gives each tire a fuel efficiency class (rolling resistance) and a wet grip class, both A to E, plus an external noise class.
Honest verdict
A tire can have a different class for each. Read both on the label; the regulation does not say one comes at the expense of the other.
Design affects several properties at once
Typical compromise
NHTSA says tire design influences durability, wet and dry traction, handling, ride comfort and rolling resistance.
Honest verdict
Compare the maker's published specifications for the tires you are considering.
Long treadwear / value
Typical compromise
The UTQG treadwear grade is a comparison of wear rate on the government test course.
Honest verdict
It does not measure rolling resistance.
Real-world impact by vehicle type
What NHTSA says about fuel economy and range. The fuel economy impact guide looks at the same question from the fuel side.
Conventional vehicles
NHTSA TireWise, fueleconomy.govRolling resistance share
NHTSA: a 10% reduction in tire rolling resistance is estimated to improve vehicle fuel economy by 1 to 2%.
Upgrade payoff
NHTSA says low-rolling-resistance replacement tires improve fuel economy and reduce fuel costs. fueleconomy.gov says properly inflated tires improve gas mileage by 0.6% on average.
Hybrid and electric vehicles
NHTSA TireWiseRolling resistance share
NHTSA says low-rolling-resistance replacement tires extend the range of electric and hybrid vehicles.
Upgrade payoff
We have no official source for a range figure by EU label class, so the page does not give one. Follow your vehicle's tire specification, including load index and speed rating.
How the rolling resistance calculator complements this guide
The tire rolling resistance calculator turns a coefficient and a vehicle mass into a calculated rolling force and power figure.
Enter a coefficient and see the force
The EU table above gives rolling resistance coefficients in N/kN; divide by 1000 for the dimensionless Crr. The rolling resistance calculator turns a Crr and a vehicle mass into a rolling force in newtons and a power figure.
Compare two coefficients side by side
Enter the Crr of two tires, for example the upper end of class A and class C from the EU table, and compare the calculated force and power at a speed you choose.
Try the companion calculator
Tire Rolling Resistance Calculator
Enter your Crr, vehicle mass, speed, and road conditions to get exact force, power, and EV range numbers for your setup.
Ways to reduce rolling resistance right now
Actions with the statements from NHTSA and fueleconomy.gov behind them. Alignment is covered in the wheel alignment guide, the age of the tires you already have can be read with the DOT date code decoder, and remaining tread with the tread depth calculator.
Maintain correct tire pressure
Highest-return actionZero costfueleconomy.gov: under-inflated tires can lower gas mileage by about 0.2% for every 1 psi drop in average pressure. Use the placard pressure, checked cold, not the sidewall maximum.
Compare rolling resistance classes when replacing tires
Depends on the tiresCheck the label or the maker's dataNHTSA says low-rolling-resistance replacement tires improve fuel economy; a 10% reduction in rolling resistance is estimated to improve fuel economy by 1 to 2%. Keep the load index and speed rating on your placard.
Follow the rotation and alignment schedule
Longer tire lifeMaintenance costNHTSA says rotation, balance and alignment can help tires last longer, and that properly inflated tires can extend tire life by 4,700 miles on average.
Remove unnecessary weight
Proportional to the loadFreeRolling resistance force = Crr × load (calculated), so a lighter load means a smaller force at the same coefficient.
Common rolling resistance myths
Common misunderstandings and what the sources say.
Myth: "The EU label A grade means the tire is best overall"
Reality: The fuel efficiency class is about rolling resistance only. Wet grip is graded separately (also A to E), and noise has its own class. Read all of them (Regulation (EU) 2020/740).
Myth: "Inflate to the number on the sidewall to save fuel"
Reality: fueleconomy.gov says to use the pressure on the driver's door jamb sticker, glove box or owner's manual, and not the maximum pressure printed on the tire sidewall.
Myth: "Rolling resistance is fixed once you choose the tire"
Reality: Inflation pressure changes it. 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.