Tire Rolling Resistance
Tires with low rolling resistance have become very popular, particularly for hybrid and fuel-efficient vehicles. If you have ever gone tire shopping, you have probably come across the phrase “Low Rolling Resistance” (LRR) and found yourself wondering what it means. Rolling resistance is the force required to maintain forward motion of a tire in a straight line with a constant speed. The greater your tire’s rolling resistance, the less fuel-efficient your vehicle becomes.
Several things can have a direct impact on a tire’s fuel efficiency. A tire’s internal construction and it’s rubber compound contribute to the rolling resistance. Tires that are designed to have a lower rolling resistance often feature thinner sidewalls, shallower tread blocks, and specialized rubber compounds. These features work together to reduce the amount of energy required to spin the tire, thereby increasing fuel efficiency.
Are Low Rolling Resistant Tires More Fuel Efficient?
Many brands are now producing fuel-efficient tires with low rolling resistance. However, there is no legislative industry standard for what requirements constitute a low rolling resistance tire. Tire manufacturers test their tire rolling resistance in their own way, typically in competition with other tires made by that manufacturer. While this will provide reliable data on the fuel efficiency in comparison to other tires made by that manufacturer, it means there is not necessarily a way to accurately compare how fuel-efficient tires from one manufacturer are compared to fuel-efficient tires from another manufacturer.
It is important to note that when you purchase a set of low rolling resistance tires, you may actually still find that your fuel efficiency decreases. This is not because the tires are not fuel-efficient, but because of the change from old worn out tires to new tires with more weight and deeper tread. As tires wear down, they become lighter, lose tread depth, allowing for them to be seemingly more efficient than new tires. In addition to the decrease in weight and tread depth, the rubber compound actually hardens over time, reducing rolling resistance. These factors could contribute to the appearance of your new fuel-efficient tires not being as fuel efficient as the old tires.
Another factor to consider is that rolling resistance tests are performed in laboratories with fixed environments. The real-world results of your low rolling resistance tires may vary. You will typically find that a low rolling resistance tire will be more fuel-efficient than a regular tire of the same size.