Rolling Resistance Calculator

What Is Rolling Resistance?

Rolling resistance is the force that opposes motion when a wheel or tire rolls on a surface. It arises from deformation of the tire and contact surface, and it slows vehicles even on level ground.

Rolling Resistance Formula

$$F = C_{rr} \cdot m \cdot g$$

$C_{rr}$ is the rolling resistance coefficient, $m$ is vehicle mass, and $g$ is gravitational acceleration (9.80665 m/s²). This is equivalent to $F = \mu \cdot N$ where the normal force $N = mg$.

Typical Coefficients

Car tires on asphalt: $C_{rr} \approx 0.015$. Bicycle tires: $\approx 0.005$. Train on rails: $\approx 0.001$. Truck tires: $\approx 0.006$.

Frequently Asked Questions

What is the rolling resistance of a 1500 kg car?

With C_rr = 0.015 on asphalt, F = 0.015 × 1500 × 9.81 ≈ 221 N. This is the force needed to maintain constant speed on level ground.

Does tire size affect rolling resistance?

Tire size has a minor direct effect. Rolling resistance depends mainly on the coefficient C_rr, which varies with tire construction, pressure, and surface type.

How is rolling resistance different from friction?

Sliding friction opposes sliding contact. Rolling resistance is energy lost during rolling deformation and is typically much smaller than sliding friction for the same normal load.

Do low rolling resistance tires save fuel?

They can reduce energy loss, but aerodynamic drag and engine efficiency often dominate at highway speeds. Proper maintenance usually saves more fuel than tire upgrades alone.

Why is bicycle rolling resistance significant?

At typical cycling speeds (15–25 km/h), rolling resistance and aerodynamic drag are comparable, so tire choice matters more for cyclists than for cars at highway speed.

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Rolling Resistance Calculator

What Is Rolling Resistance?

Rolling Resistance Formula

Typical Coefficients

Frequently Asked Questions

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