The Lowdown on Low Rolling Resistance

Thursday, July 22, 2010 by Cooper
Wet track testWith the advent of new green propulsion technologies for cars, light trucks, and SUVs, it is only natural that tire manufacturing companies would take an interest in developing more fuel-efficient tires. Market demand for such tires will only continue to increase as the fleet of hybrid, electric, and diesel-powered vehicles grows and becomes more and more ubiquitous.

Certainly, lowering tire rolling resistance by optimizing a tire’s weight, internal structure, tread design and tread compound make it possible to reduce vehicle fuel consumption and consequently, lower emissions of carbon dioxide and other greenhouse gases. But fuel efficiency comes with a price. And as is the case with tires across performance categories, there are some trade-offs when it comes to low rolling resistance tires.

My first experience driving a vehicle with the new crop of low rolling resistance tires came last year while visiting the Continental Tire Proving Grounds in Uvalde, Texas. Among the driving exercises was a braking test: we had to accelerate a 2010 Ford Escape equipped with LRR tires down a (dry) straight to a speed of 45 mph and then slam the brakes once the vehicle hit a wet pad. We tested summer and all-season tires, and one set of low rolling resistance (LRR) tires on the Escape. This being my first experience with LRR tires, I was surprised at the results: the LRR tire took significantly longer to come to a complete stop.

A few months later as part of Tire Rack's testing program, we tested four different sets of LRR tires on four identical Toyota Prius. Our road route consists of expressway, state highway and county roads to provide a variety of road conditions that include smooth and coarse concrete, as well as new and patched asphalt. The route allows our team to experience noise comfort, ride quality and everyday handling, just as most drivers do during their drive to school or work. After the test, I noticed that when compared to other non-LRR tires, there was a considerable difference in ride quality. We also performed dry and wet track tests with the Prius and our BMW 3 Series and the LRR tires showed considerably less grip on wet than their standard counterparts -- especially on the Bimmer.

So after all these tests, my recommendation is this: your tire selection should match not only how you drive, but what you drive. I would definitely recommend LRR tires to customers who drive hybrid cars and for whom fuel efficiency is the ultimate goal. Given the substantial differences in wet traction and braking distances on wet, LRR tires may not be suitable to be used on performance cars being driven in a more spirited manner.

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