Quick Answer
- Rolling resistance force = Crr x mass x 9.81 (flat road). A 1,500 kg car with Crr 0.0090 (the EU class C limit for passenger tires) is 132 N, which is 3.3 kW at 90 km/h (calculated).
- With Crr 0.0065 (the class A limit) the same car is 96 N and 2.4 kW, 0.9 kW less at that speed (calculated from the class limits, not a tire test).
- The EU tire label gives the coefficient as a class (A to E) from the rolling resistance in N/kN. Divide N/kN by 1000 to get Crr.
Passenger car tire, class C: 7.8 to 9.0 N/kN.
The coefficient is used as entered. We have no official source for surface multipliers, so none is applied.
Results
132.4 N
Crr effective: 0.0090
0.0 N
Grade: 0% → 0.00°
252.7 N
½ × 1.225 × 0.3 × 2.2 × v²
385.1 N
Get a plain-English explanation of your results and what they mean for your vehicle.
Tire Rolling Resistance Chart: EU Label Classes in N/kN
Rolling resistance coefficient limits for each fuel efficiency class, from Regulation (EU) 2020/740 Annex I. Divide by 1000 for Crr.
| Class | Passenger car (C1) | Light truck (C2) | Heavy truck (C3) |
|---|---|---|---|
| A | 6.5 or less | 5.5 or less | 4 or less |
| B | 6.6 to 7.7 | 5.6 to 6.7 | 4.1 to 5 |
| C | 7.8 to 9 | 6.8 to 8 | 5.1 to 6 |
| D | 9.1 to 10.5 | 8.1 to 9 | 6.1 to 7 |
| E | 10.6 or more | 9.1 or more | 7.1 or more |
Rolling Force and Power by Class Limit
A 1,500 kg car at 90 km/h on a flat road, using each class limit as the coefficient. Calculated, aerodynamic drag excluded.
| Coefficient used | N/kN | Crr | Force | Power | Energy |
|---|---|---|---|---|---|
| C1 class A limit | 6.5 | 0.0065 | 96 N | 2.4 kW | 26.6 Wh/km |
| C1 class B limit | 7.7 | 0.0077 | 113 N | 2.8 kW | 31.5 Wh/km |
| C1 class C limit | 9 | 0.0090 | 132 N | 3.3 kW | 36.8 Wh/km |
| C1 class D limit | 10.5 | 0.0105 | 155 N | 3.9 kW | 42.9 Wh/km |
| C1 class E lower limit | 10.6 | 0.0106 | 156 N | 3.9 kW | 43.3 Wh/km |
Rolling Power by Mass and Speed (Crr 0.0090)
| Mass | Force | 50 km/h | 90 km/h | 110 km/h | 130 km/h |
|---|---|---|---|---|---|
| 1,000 kg | 88 N | 1.2 kW | 2.2 kW | 2.7 kW | 3.2 kW |
| 1,500 kg | 132 N | 1.8 kW | 3.3 kW | 4.0 kW | 4.8 kW |
| 2,000 kg | 177 N | 2.5 kW | 4.4 kW | 5.4 kW | 6.4 kW |
| 2,500 kg | 221 N | 3.1 kW | 5.5 kW | 6.7 kW | 8.0 kW |
| 3,000 kg | 265 N | 3.7 kW | 6.6 kW | 8.1 kW | 9.6 kW |
Effect of Grade (1,500 kg, Crr 0.0090)
| Grade | Rolling force | Grade force | Total |
|---|---|---|---|
| 0% | 132 N | 0 N | 132 N |
| 2% | 132 N | 294 N | 427 N |
| 5% | 132 N | 735 N | 867 N |
| 8% | 132 N | 1173 N | 1305 N |
Power is the force times speed. The engine rpm calculator and the tire pressure calculator cover the drivetrain and inflation sides.
Rolling Resistance Formula and Sources
Rolling force
F = Crr x m x g x cos(grade angle). For 1,500 kg and Crr 0.0090 on a flat road: 0.0090 x 1500 x 9.81 = 132 N.
Rolling power
P = F x v, with v in m/s (km/h divided by 3.6). 132 N at 90 km/h (25 m/s) is 3311 W, or 3.3 kW.
Unit of rolling resistance
Crr has no unit. The EU label gives rolling resistance as a coefficient in N/kN (newtons of force per kilonewton of load), and 1 N/kN = 0.001 Crr.
Grade and drag
The calculator adds grade force m x g x sin(angle) and, if turned on, aerodynamic drag 0.5 x air density x Cd x area x v squared, so you can see each part separately.
| Source | Statement (paraphrased) |
|---|---|
| Regulation (EU) 2020/740, Annex I | Defines the fuel efficiency classes A to E by rolling resistance coefficient in N/kN for passenger car (C1), light truck (C2) and heavy truck (C3) tires. The class limits in the table above come from it. |
| NHTSA, tire fuel efficiency information | Tire design and inflation pressure influence rolling resistance and fuel economy. NHTSA estimates that a 10% reduction in tire rolling resistance improves fuel economy by 1 to 2%. |
| 49 CFR 575.106, US tire fuel efficiency consumer information program | Applies to replacement passenger car tires. It does not apply to light truck tires, deep tread or winter-type snow tires, space-saver or temporary spares, or tires with rim diameters of 12 inches or less. |
More on how tires affect fuel use in the rolling resistance guide and the guide to how tires affect fuel economy.
How to Calculate Rolling Resistance
- 1Enter mass and speed. Type the vehicle mass and speed, or click an example to fill the fields.
- 2Choose a coefficient. Pick an EU class limit, or choose Custom Crr and enter the coefficient from the tire maker's data or a test report.
- 3Set the road grade. Use the slider for grade from -15% (downhill) to +15% (uphill). Grade force is calculated separately.
- 4Add aerodynamic drag (optional). Turn on aerodynamic drag and enter your vehicle's drag coefficient, frontal area and air density.
- 5Read the results. Use the Forces tab for N or lbf, the Power tab for W, kW or hp, and the Efficiency tab for road-load energy and the plus or minus 10% Crr comparison.