Vehicle manufacturers are fueling a trend toward higher-speed-rated tires as original equipment, with the H-rated tire getting the gravy as the industry's new broadline tire.
Although vehicle manufacturers, tire makers and tire dealers couldn't quantify all the changes over the past few years, all agreed that H-rated tires-maximum speed 130 mph, or 210 km/h-are becoming increasingly important as car makers specify them as OE for more and more vehicle models.
``Your American car industry is going more for higher speed ratings and lower profiles,'' said Randy Mayers, president of Sabal Chase Service & Tire Center, a high-performance tire specialist in Miami. ``It's the trend right now. Your S- and T-rated tires (maximum speeds 112 and 118 mph, respectively) are going downhill, while tires rated H, V, W and Y are on the upswing.'' (V-rated tires are built for a maximum speed of 149 mph, W-rated for 168 mph and Y-rated for 186 mph.)
``S-rated and T-rated tires are going away,'' added Bob Toth, Goodyear marketing manager for automobile tires. ``In the near future, there will be no S- and T-rated high-performance tires. All will be H-rated or higher.''
A change in the driving habits of U.S. motorists is the main impetus behind the growth of H-rated tires, according to Rick Brennan, high-performance brand manager for Kumho Tires U.S.A. Inc.
``I guess you could say it's the new broadline line, because it's the OE tire on the kind of car-as opposed to an SUV or a light truck-that the average American drives.'' Mr. Brennan said. ``Eight years ago, the most popular passenger car was the Ford Taurus; today, it's the Toyota Camry. Honda, Nissan and Toyota use more H-rated tires, and also more lower-aspect-ratio tires, than Detroit does.''
Mr. Toth agreed. ``If you look at any little Honda today, it will have H-rated tires,'' he said.
Mr. Brennan quoted production figures compiled by the Rubber Manufacturers Association to demonstrate his point. In 1996, he noted, U.S. production of H-rated tires totaled about 14 million. By 2003, that number had nearly doubled to 25.2 million, of which 18 million were in the 60-65, low-aspect-ratio series.
But Detroit, like the Asian and European manufacturers, also is moving in the direction of H-rated OE tires, according to David Cowger, a tire engineer at General Motors Corp.
It's difficult to discuss which GM models now use H-rated OE tires that didn't five years ago, according to Mr. Cowger. That's because one model can have three different levels of accessories and performance, calling for three different types of tires.
Nevertheless, he added, the different grades within a single model at GM have seen their sizes and speed ratings creep up and their aspect ratios go down.
``A few years ago, a model might have a 15-inch tire for the basic type, a 16-inch touring tire for the next grade up, and a 16-inch, S- or T-rated tire for the top-of-the-line vehicle,'' he said. ``But now the three levels might have the 15-inch tire rated S or T for the basic version, a 16-inch H-rated tire for the mid-level type, and a 17-inch V-rated tire for the premium version.''
The construction of vehicles for higher speeds and higher performance dictates the OE fitment of tires with higher speed ratings and shorter sidewalls, according to Matt Edmonds, vice president of marketing for Tire Rack, the South Bend, Ind.-based mail-order and online tire marketer. ``It's part of the evolution of tire production,'' he said.
Mr. Mayers of Sabal Chase said he believes issues of both safety and economy led to the growth in demand for H-rated tires.
``H-rated tires have come down in price a lot, so it's more economical to specify them as OE,'' he said. ``It's hard to relate exactly what's happening, but H-rated tires are definitely found a tier below where they used to be.''