By Deb Acord
Spectators at this summer’s Pikes Peak International Hill Climb in June were awed by what they saw. They cheered as Japan’s Nobuhiro “Monster” Tajima attacked the high-altitude 12.42-mile course in record time – 9 minutes, 51 seconds.
They had gotten to their viewing spots on the gravel shoulders of the Pikes Peak Highway by crawling up the mountain at much lower speeds than “Monster” – who drove much of the route at more than 90 mph.
Despite the differences in driving styles, few probably realized there were similarities between their vehicles and the turbo-charged, 910-horse power Suzuki SX4 –specifically, the way their tires gripped the road.
Chances are many of the family minivans, sedans and SUVs that got them up the mountain to watch their favorite race are running on performance tires modeled after racing tires.
In 2010, about a fourth of passenger replacement tires shipped – 53 million – were designated as high-performance (HP) or ultra-high performance (UHP), according to Kevin Rohlwing, senior vice president for the Tire Industry Association.
The growing popularity of performance tires has to do with consumers’ desire for better handling. “Automakers are using more performance tires on typical 2-door and 4-door sedans as they try to meet the needs of drivers,” Rohlwing says.
The first generation of performance tires were inspired by racing circuits and modeled after the handling required of Formula 1 racing cars. They soon found their way off the racetrack and onto the classic muscle cars of the 1980s – Chevy Corvettes, Ford Mustangs and Pontiac Firebirds.
Today’s performance tire “is engineered to provide the driver with maximum handling ability,” Rohlwing says.
That’s the biggest advantage of a performance tire, he says. “Every aspect of the design and construction of the tire is engineered to give the driver the most responsiveness. People who want their cars to ‘ride on rails’ will see the most benefits from a performance tire.”
Some performance tires stand out because of their low profile, but Rohlwing says, “Not all low-profile sidewall tires are in the performance category.”
What makes them deserve the performance title? According to Edmunds.com, performance tires feature large tread blocks with a high lateral stiffness, which wide grooves that expel and separate water.
“Almost everything about a performance tire is different from the average tire,” Rohlwing says. The construction, rubber compounds, and tread design determines the category; not the profile of the sidewall.
High performance tires generally have speed ratings of H (sports sedans and coupes, up to 130 mph), V (sports sedans, coupes and sports cars, up to 149 mph), or Z (in excess of 149 mph). UHP tires are speed-rated V, Z or Y (up to 186 mph).
The most common differences between passenger tires and performance tires are tread life and ride comfort, Rohlwing says. “The sidewall on a performance tire is stiffer than the average tire because sidewall flexing is not an optimal feature when the goal is handling and responsiveness. Likewise, the tread compound of a performance tire is designed for maximum grip so it cannot be expected to deliver the same mileage as a tire with a tread compound engineered for the best tread wear.”
IntelliChoice, the car-buying website, says grip is everything. High-performance tires should have impressive grip, on both wet and dry surfaces, and a crisp steering feel. With ultra-high-performance tires, IntelliChoic says “grip is king,” along with precise steering feel.
Know your tires
Do you know what your tires can tell you? Since 2000, all tires are required to have identification numbers – 10, 11 or 12 letters and/or numbers that tell you where the tire was manufactured, the tire size and manufacturer’s code, and the week and year the tire was manufactured.
Look for DOT on your tire, and at the end of the series of numbers and letters, you’ll find the week and year it was manufactured. For example, the last four digits 3208 mean the tire was manufactured during the 32nd week of 2008.