Bob Ulrich

Editor

Bob Ulrich was named Modern Tire Dealer editor in August 2000. He joined the magazine in 1985 as assistant editor, and has been responsible for gathering statistical information for MTD's "Facts Issue" since 1993. He has won numerous awards for editorial and feature writing, including five gold medals from the International Automotive Media Association. Bob earned a B.A. in English literature from Ohio Northern University and has a law degree from the University of Akron.

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How low can low rolling resistance go?

By: Bob Ulrich

Until tires become nothing more than ball bearings, low rolling resistance in a tire has its limits. But we're far from reaching those limits.

At a recent ride and drive event in Denver, Colo., Yokohama Tire Corp. showcased two of its newest tires: the dB Super E-spec and Avid ENVigor. Both are promoted as having comparatively low rolling resistance.

According to Michael Crabbe, a merchandising specialist for Yokohama's central zone, no other tire in the company's lineup has less rolling resistance than the E-spec. Not surprisingly, it is designed for environmentally friendly hybrid vehicles. The ENVigor, however, has pretty low rolling resistance for an all-season performance touring tire.

Crabbe says there are three main ways to lower the rolling resistance in a tire.

1. Compounding.

2. Design features.

3. Weight.

The key to the Super E-spec is its compounding. The ENVigor combines a new low rolling resistant silica compound with a tread design that helps the tire roll more freely without sacrificing grip.

"The intersection of the tread has a tapered edge to provide a smoother transition while the tire's rolling," he says. In addition, the tire's profile reduces weight in the tread area.

Crabbe adds that the ENVigor has up to 20% less rolling resistance than conventional tires such as the tire line it replaced: the Avid H4S, V4S and W4S.

Based on its own testing of size 215/60R16 tires on a 2008 Toyota Camry, Yokohama claims the ENVigor has lower rolling resistance than tires it considers comparable: the Bridgestone Turanza with Serenity, Bridgestone Potenza GO19 Grid and Michelin Pilot Exalto A/S. The ENVigor did not, however, beat out the Michelin Primacy MXV4 in that category.

What does all this mean? If a tire rolls more freely -- for whatever reason -- it uses less energy. the less energy expended, the less fuel consumed. And to the consumerr, less fuel equals greater fuel efficiency equals less money spent.

The savings may not be noticeable to your customers. But as long as tire manufacturers strive to lower rolling resistance while maintaining or improving on characteristics such as wet and dry grip and long life, we all win.

Related Topics: Fuel efficiency, Green, Low rolling resistance, Yokohama Avid