Low Rolling Resistance Tires

Advantages

• Can improve fuel consumption and greenhouse gas (GHG) emissions by as much as 4.5%¹
• Equipping your car with low rolling resistance replacement tires can help reduce your fuel consumption and greenhouse gas emissions

Disadvantages

• Traction may be affected by modifying a tire's tread to reduce rolling resistance
• Although strength and endurance are regulated, it is not known if a lower rolling resistance can reduce these tire characteristics
• Unless branded by a manufacturer, there is no means to compare rolling resistance of one tire to another

On average, more than 80% of a vehicle's fuel energy is wasted through various thermal, frictional and standby losses². However, low rolling resistance tires can help reduce this loss of energy by making vehicles more efficient as they drive down the road. In fact, recent studies performed by manufacturers and third party evaluations have found that low rolling resistance tires can help reduce a vehicle's fuel consumption by 1.0% to 4.5%.

Rolling resistance: the science

When a rubber tire makes contact with the road, it creates frictional forces that make traction, cornering, acceleration and braking possible. To maintain this contact, a tire continually deforms and reshapes itself as it rolls over the road, requiring energy that could otherwise be used to drive the vehicle.

Contact with the road creates an opposing force called 'rolling resistance'. The more energy used to deform and reshape the tire, the higher the rolling resistance. And the higher the rolling resistance, the more fuel must be burned to replace the lost energy. This results in higher fuel consumption and more tailpipe emissions.

How tires achieve low rolling resistance

Several vehicle manufacturers already install low rolling resistance tires on some of their vehicles. But if drivers replaced their worn out tires with low rolling resistance ones as well, it could have an impact by reducing fuel consumption and greenhouse gas emissions in Canada.

Did you know?

Other factors that can help reduce the environmental impacts of tires include:

• Tire Pressure - Tires designed to operate at higher pressures reduce the deformation of the tire.
• Rubber Compounds - Harder and lighter compounds do not deform as much, thus requiring less energy.
• Dimensions - Narrow, low profile tires generally require less energy to deform.
• Weight - Tires with less material require less energy to deform and reduce the unsprung weight of the vehicle.
• Tread Pattern - Smooth tread patterns roll more easily than coarse tread patterns. Short lugs and narrow gaps improve rolling resistance.
• Compounding Methods - Using alternatives to toxic oils during fabrication helps reduce environmental impacts.

eTV study on low rolling resistance tires

Despite the benefits outlined above, there are no universal standards that can be used to identify 'low rolling resistance' tires from other type of tires. eTV is helping to address this issue by acquiring and testing a variety of low rolling resistance tires to determine their "rolling resistance coefficients".

Tests will be conducted on a number of different tires mounted on 15 and 16-inch rims - the most common tire sizes in Canada - to determine how rolling resistance is influenced by vehicle size, tire width and profile. Results will be used to inform Canadians about the types of low rolling resistance tires available in Canada, and whether they can help reduce fuel consumption and pollutants from passenger vehicles.

¹Green Seal, 2003
²National Academy of Sciences,2006

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