Everything You Need to Know About Low Rolling Resistance Tires

Posted on: March 27, 2016

Are you tired of paying an arm and a leg at the gas pump? Do you want to squeeze more miles out of your car every fill up? In addition to buying a fuel-efficient car, consider low rolling resistance tires the next time you need a replacement set in order to get more fuel savings. Let’s find out more about these tires so you won’t be burning your hard-earned money.

What Is Low Rolling Resistance?

When your vehicle burns fuel, much of the energy produced goes into heat generated from the engine and other components. Another source of energy loss is rolling resistance.

Rolling resistance is the energy required to keep the tires moving forward on the road. Whenever your car moves, the tires make contact with the road. The road pushes back, causing the tire to deform or flatten slightly. Also, the less air pressure present in your tires, the more the tire deforms, and the more energy it takes for the tires to bounce back to shape. Less rolling resistance equals less energy wasted.

Determining Rolling Resistance

Calculating rolling resistances requires specialized lab setup. Tires are set up on a spinning dynamometer, and the force needed to keep the tires rolling is measured. Test details are in the SAE’s J1269 and J2452 specifications.

How to Reduce Resistance?

Low rolling resistance tires can be thought of as “green” tires, since they end up using less fuel. One way to reduce rolling resistance is to increase air pressure in your tires to the recommended amount. With increased tire pressure, the tire ends up getting less deformed while going down the road, resulting in less energy wasted. But, why not inflate the tires well above the recommended amount?

When you inflate tires well above recommendations, you end up causing the tire to have less contact with the road and, therefore, less traction. This can prove especially difficult or even dangerous when trying to steer or brake in wet or icy conditions.

Besides having an appropriate amount of air pressure, designers can reduce rolling resistance through engineering. Engineers reduce resistance by introducing combinations of materials such as natural and synthetic rubber, designing stiffer sidewalls, and reducing tread depth. Each of these green innovations help reduce tire deformation, leading to fuel savings.

Fuel Savings 

Cars burn much of the fuel or heat generated by the engine and other components. This includes rolling resistance, which burns 7% of total fuel while the car is on the highway. It is estimated that using low rolling resistance tires can reduce fuel usage by as much as 6%. Though the amount may be small, it will add up over time.

Suppose you had a car that got 20 miles per gallon (mpg). Installing rolling resistance tires should increase fuel-efficiency by 6%, or by nearly 1 mpg. Let’s see how much of a difference this really makes. Based on the Department of Transportation’s average figures, the average commute is 24 miles to and from work.

Over the course of a week, you would travel 120 miles based on this average. At 20 mpg, you end up using 6 gallons, while at 21 mpg you end up using about 5.7 gallons of gas. At the peak gas price of $5 per gallon, this would give a savings of $1.50 per week. In a year, you would end up saving $72.  Though this may seem very little, over 4 years, you would save nearly $280!

Tire Labels

Currently, all tires have labels indicating traction and tread wear through the Uniform Tire Quality Grading system. Unfortunately, the label does not include rolling resistance, which can vary greatly among manufacturers. Recently, Congress passed laws requiring labels to indicate fuel efficiency.  Unfortunately, label content is still being negotiated among the different stakeholders and still does not include rolling resistance values.

Trade Offs

Although low rolling resistance tires may reduce fuel consumption, they may also reduce maneuvering and braking capabilities. When selecting a low rolling resistance tire, consider the traction rating on your tires, and make sure to select a rating suitable for these conditions. According to the Green Seal’s Choose Green Report, you should choose a tire with an A rating.

In some cases, low rolling resistance tires may be more expensive when taking into account multiple factors. Consider fuel savings and the current price of gas to see if buying these tires is worth the added cost.

Conclusion

With millions of cars on the road consuming ever-increasing amounts of precious energy resources, it is now imperative to conserve as much energy as possible. In addition to driving high-mileage vehicles, using low-rolling resistance tires is a great way to squeeze more miles from a tank of gas!