Hybrid Tires: The Low-Rolling Resistance Debate

by Jack Payton

in Parts

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Among the many factors that lead consumers to purchase a hybrid vehicle, fuel efficiency reigns supreme. Sure, performance andstyle – not to mention a desire to stay a step ahead of the Jones’ – also influence a potential owner’s decision, but by-and-large, it is a desire to improve gas mileage that provides the biggest impetus for those that purchase hybrids such. The promise of saving considerable coin at the fuel pump and a desire to reduce carbon footprints is what primarily drives hybrid owners to be on the forefront of automotive innovation.

But just because hybrid owners are concerned – some might say obsessed – with fuel efficiency, doesn’t mean they should let factors such as performance and safety go by the wayside. And anecdotal evidence suggests that some hybrid drivers, and those in the industry that cater to their demands, are too willing to sacrifice security and function in order to obtain a few extra MPGs.

Tire manufacturers have been busy attempting to find that delicate balance between fuel efficiency and performance/safety, and though the results have been uneven, the general trend has been positive. For consumers thinking about purchasing a hybrid vehicle, or those who already have one and are shopping for new tires, there are a number of considerations to weigh.

Most hybrid vehicles are stocked with low-rolling resistance tires (LRRTs), designed to maximize gas mileage, and studies indicate that they are largely effective in achieving that aim. However, there are also indications that there is some significant trade-off to be made in order to achieve the ultimate in fuel efficiency and that these compromises may sometimes be self-defeating to drivers looking to get the most bang out of their automotive buck.

Early LRRTs were simultaneously acclaimed for their fuel-efficiency and lampooned for their durability. Follow-up designs have attempted to ease some of these concerns; for instance, they Chevy Volt comes equipped with Goodyear Fuel Max LRRTs, which were purported to “strike a balance between low rolling resistance and long life.” Unlike the first LRRTs, the Fuel Max tires are guaranteed for 65,000 miles, and there are some tire manufacturers that are offering LRRTs with a 90,000 mile warranty. But are these models less fuel efficient than their less-durable counterparts? Well, that depends on who you ask.

Before you can make the determination which, if any, LRRTs you should roll with, you have to understand what it is that makes these low-resistant tires unique. LRRTs are designed with a tread compound that is said to reduce internal friction, and the tread has been engineered to keep the surface patch – the part of the tire touching the road at a given time – as small as possible. LRRTs are also constructed to be inflated in such a way that maximizes fuel efficiency. In short, the harder the tire, the lower the rolling resistance. The lower the resistance, the less energy that is swallowed up by the road.

And it’s proven that these engineering advancements have led to a tire that is more fuel efficient on a MPG basis, but not necessarily when overall cost-per-mileage is concerned. If one gets 25% less life from their tires, is it worth it to get an extra 5% in fuel efficiency? There are no easy answers here, as each tire has its own quirks and characteristics and there are many unknown variables.

What is known is that most LRRTs sacrifice some traction for the lower resistance. Decreased traction raises a number of potential safety issues. Among the issues cited as possible safety hazards of using LRRTs:

  • Decreased grip, particularly in wet or slick conditions
  • Loss of stopping distance – the length it takes to stop when braking
  • An increased blowout potential (a particular danger when tires are over-inflated)
  • Instability in curves
  • Hydroplaning

Now this isn’t to suggest that LRRTs are inherently unsafe, they aren’t; all the tires on the market go through rigorous safety tests to ensure that they are safe under normal conditions, and the above named factors are diminished almost entirely when the driver ensures that the tires are properly inflated – too low and you lose efficiency, too high and you compromise safety – and refrains from any dangerous driving techniques.

The bottom line may come down to who you are, where you live and what you value most out of your hybrid. If you are a somewhat aggressive driver, for whom performance is of the utmost importance, you may be better off going with a softer tire that emphasizes traction more than fuel economy. Similarly, if you live in a region where whether conditions change frequently or where there is long cold/wet winters, you might want more grip on your tires than LRRTs traditionally offer.

However, if you are an ardent fuel efficiency guru, and possess mostly mellow and careful driving habits, the lowest-resistance tires on the market might be for you.

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