Rolling Resistance Calculator
Find the rolling resistance force, power and energy per km of a car, bike or train, then see how far it coasts and how air drag compares.
🛞 What is Rolling Resistance?
Rolling resistance is the force that opposes the motion of a wheel, tyre or ball as it rolls over a surface. It is not sliding friction. A rolling tyre flexes where it meets the road, and because the rubber does not return all the energy it stores while deforming, some energy is lost as heat on every turn of the wheel. The loss shows up as a retarding force. For a given tyre and surface it is conveniently described by a dimensionless coefficient of rolling resistance, Crr, so that the force is simply Crr times the normal force.
Rolling resistance matters wherever vehicles move. It sets the energy a car or an electric vehicle uses to cruise at low and moderate speeds, it is the main resistance a cyclist feels in town, it decides how far a train or a trolley will roll when the engine is cut, and it is a key input to range estimates and fuel economy models. Tyre makers publish low rolling resistance designs because a small drop in Crr gives a steady saving on every kilometre. Engineers also measure it with coast-down tests, timing how a vehicle slows from a known speed.
A few distinctions help. Rolling resistance is not the same as the friction that lets a wheel grip the road, which is static friction and can be very high. The two are different effects on the same tyre. It is also not air drag: rolling resistance is nearly constant with speed, while aerodynamic drag grows with the square of speed, which is why this page has a mode that adds the two and finds the speed where they are equal. The coefficients used here are typical values for tyre and surface pairs. Real figures depend on tyre construction, inflation pressure, temperature, load and speed, so measured data should replace them for design work.
This calculator gives the rolling resistance force, the power it takes at a chosen speed, and the energy per kilometre, along with a table comparing typical tyres and surfaces at your mass and speed. A coast-down mode gives the distance and time to stop, and a combined mode adds air drag. For the physics of sliding rather than rolling, see the friction calculator.
📐 Formula
📖 How to Use This Calculator
Steps
💡 Example Calculations
Example 1 — A Car at 100 km/h
1500 kg car, Crr = 0.012, level road, 100 km/h
Example 2 — A Cyclist at 25 km/h
85 kg rider and bike, road tyres on smooth asphalt (Crr = 0.004), 25 km/h
Example 3 — The Same Car on a 10 Degree Slope
1500 kg car, Crr = 0.012, 10° slope, 60 km/h
Example 4 — Coasting From 100 km/h, Rolling Resistance Only
1500 kg car, Crr = 0.012, drag coefficient set to 0
Example 5 — The Same Coast With Air Drag
1500 kg car, Crr = 0.012, Cd = 0.30, A = 2.2 m², ρ = 1.225 kg/m³
Example 6 — A Cyclist Coasting From 20 mph
85 kg rider and bike, Crr = 0.004, Cd = 0.9, A = 0.5 m², 20 mph
Example 7 — Rolling Plus Air Drag for a Car at 100 km/h
1500 kg car, Crr = 0.012, Cd = 0.30, A = 2.2 m², 100 km/h
Example 8 — Rolling Plus Air Drag for a Cyclist at 30 km/h
85 kg rider and bike, Crr = 0.004, Cd = 0.9, A = 0.5 m², 30 km/h
❓ Frequently Asked Questions
🔗 Related Calculators
What is the formula for rolling resistance?
The rolling resistance force is F = Crr x m x g x cos(slope angle), where Crr is the dimensionless coefficient of rolling resistance. For a 1500 kg car with Crr = 0.012 on level ground, F = 0.012 x 1500 x 9.80665 = 176.52 N.
What is a typical rolling resistance coefficient for a car tyre?
Typical values are about 0.01 to 0.015 for car tyres on concrete or new asphalt, about 0.007 to 0.014 for new passenger tyres measured to SAE tests, and lower for low rolling resistance tyres. The presets here are typical, not tested values.
What is the rolling resistance of a bicycle?
A road bicycle tyre on smooth asphalt has Crr near 0.004, and on rough paved road about 0.008. An 85 kg rider and bike at 25 km/h then needs about 3.3 N of force and 23 W of power to overcome rolling resistance.
How do you calculate the power needed to overcome rolling resistance?
Power is force times speed, P = Crr m g v. A 1500 kg car with Crr = 0.012 at 100 km/h (27.78 m/s) needs 176.52 x 27.78 = 4903 W, or 4.90 kW, which is about 6.6 hp, just for rolling resistance.
How much energy does rolling resistance use per kilometre?
The energy per kilometre equals the force times 1000 m. The 176.52 N car uses 176.52 kJ per km, which is 49.03 Wh/km or 4.90 kWh per 100 km, regardless of speed in this model.
How do you calculate coasting distance with rolling resistance?
With rolling resistance alone the deceleration is Crr g, so the coasting distance is v squared over 2 Crr g. From 100 km/h with Crr = 0.012 that is 3278 m taking 236 s. Air drag shortens it a lot, to about 1888 m for a typical car.
Is rolling resistance the same at every speed?
In the simple model used here it is constant, but real tyre rolling resistance rises slowly with speed because of heating and standing waves. For ordinary speeds the constant-coefficient model is a good first estimate.
How does rolling resistance compare with air drag?
Rolling resistance is roughly constant while air drag grows with speed squared. For a 1500 kg car with Cd 0.30 and 2.2 m2 frontal area they are equal at about 75 km/h. At 100 km/h rolling resistance is only about 36 percent of the total.
Does rolling resistance depend on the size of the wheel?
Generally larger wheels have a somewhat lower coefficient for the same tyre type and surface, but tyre construction, pressure and surface matter far more. This calculator takes Crr directly, so enter the value that applies to your wheel.
What is the rolling resistance coefficient of a train wheel?
Steel wheels on steel rails are far lower than rubber tyres, around 0.001 to 0.002 in typical figures, which is a main reason rail travel is energy efficient. The preset uses 0.001 as a typical value.