Rolling Resistance is a force that
resists the motion of a body rolling on the surface.
In simple physics terms its the
resistant force acting in the oposite direction of a
object in motion.
Rolling Resistance can be caculated using the following equation: Fr= cW, or Fr=cma
Fr: rolling resistance, rolling friction
W: normal force, or weight of the body
m: mass
a: acceleration of gravity
c: rolling coefficents
The most important aspect of the whole equation is the rolling coefficent and understanding what it means. Usually you can find charts for rolling coefficents based on the material the road is built of.
The following chart is typically used for basic cars and bikes for rolling coefficents to calulculate rolling resistance.