Rolling Resistance and the Environmental Impact of Tires
January 12th, 2009While many drivers are in favor of more environmentally positive mobility, most are unaware of how tires can reduce a vehicle’s environmental impact by improving its energy performance. In a recent survey by Michelin, tires are mentioned as a source of pollution by only 24 percent of those surveyed. In fact, due to rolling resistance, tires can have a significant impact on vehicle fuel economy and the environment in general.
What is rolling resistance?
With each rotation of the wheel, the shape of the tire changes slightly under the weight of the vehicle as the tire makes contact with the road. As its structure changes, the tire’s components heat up and some of the energy transmitted by the engine is lost. This is the phenomenon known as rolling resistance. Since energy is needed to keep a vehicle moving forward, lowering a tire’s rolling resistance makes it possible to reduce fuel consumption and, consequently, lower emissions of CO2 and other greenhouse gases.
Rolling resistance is one of the five forces a vehicle must overcome in order to keep moving. The others are: 1) air resistance (which depends on vehicle speed), 2) significant inertia forces when accelerating (such as in city driving), 3) gravity when driving uphill, and 4) internal friction (involving the transmission, for example).
When it comes to rolling resistance, all tires are not equal, with differences of up to 50 percent on tires designed to equip the same vehicle.
Lowering CO2 emissions: A priority for Michelin’s research and development teams
An aggressive commitment to reducing tire energy consumption has guided Michelin throughout its history. The increasing importance of this challenge is illustrated by the fact that the world’s current estimated 830 million vehicles, which are responsible for 18 percent of global CO2 emissions , are expected to double by 2030 . With its green energy saving tires, Michelin is demonstrating its concern for preserving energy resources. This is particularly critical since at current consumption levels. At least one major authority believes that the world’s easily accessible oil reserves could be depleted in an estimated 31 years.
