At what point does “low” become “standard?”
That's the question the tire industry is asking itself as low-profile passenger tires continue to gain a larger share in the consumer OE business and the aftermarket.
According to Tire & Rim Association data, the number of auto rim diameters and tire aspect ratios recognized by the organization has increased to 328 from 213 since 2000. About 86 percent of these new sizes have rim diameters of 18 inches or larger and aspect ratios of 55 percent or lower. Nearly half of all recognized aspect ratios are 50 percent or lower.
“Performance tires aren't just for sports cars anymore,” said Bob Toth, Goodyear's director of products and innovation for North America, during a panel discussion at the 2010 ITEC Show in Cleveland. “Performance tires are coming on a wide variety of cars, and it's because the OEMs are using the tire as an integral part of the suspension to fine tune it to optimize stopping and handling.
“…You could say that high-performance tires were born in racing and they transgressed over to niche market street products, but the reality is they're becoming appreciably the norm in the market place.”
Mark Chung, Yokohama Tire Corp.'s director, corporate strategy and planning, concurred, noting even economy cars are coming equipped with lower-profile sizes.
“This trend will continue as we are now seeing everyday vehicles, such as the (Toyota) Camry or (Chevrolet) Malibu, ship from the factory with larger wheel diameters versus the previous generations,” he told Tire Business recently. “If auto shows provide any accurate forward-looking indications, it appears this trend will continue. The opportunity for tire manufacturers and dealers alike is to develop and sell tires that are compatible with vehicles with lower-profile tires.”
The trend is being driven primarily by auto makers, said Matt Edmonds, vice president of South Bend, Ind.-based Internet/mail order retailer Tire Rack, as they aim to provide customers with all-around sportier vehicles and better handling.
'The tire manufacturers have gone a long way in developing tires to maintain ride quality as they've reduced the sidewall of the tire, and at the same time they've had to strengthen the sidewall of the tires…. All of that at the same time the OEMs are squeezing them to get everything they can out of the tire from a rolling-resistance standpoint to improve the CAFE (corporate average fuel economy) numbers,” he said.
Mr. Edmonds added that while most people associate low-profile tires with performance tires, that is no longer an accurate assumption.
“People are looking at the aspect ratio of the tire and saying, 'Well, gosh, it's a low-profile tire, so it's gotta be a performance tire.' That's not necessarily true anymore,” he said. “You have a lot of vehicles that have a 50-, 55-, 60-aspect ratio tire that has an all-season grand touring tire on it, not necessarily a performance tire.
“…The fact that you have a lot of vehicles—SUVs and light trucks—coming with what people are perceiving as low-profile tires, it's being driven by the packaging by the OEMs wanting the appearance of a big wheel on the vehicle but also going to a larger wheel.
“As that wheel gets bigger, it gives them more room behind that wheel to work—to put brakes, to put suspension components, to have clearance to have those kinds of things happen behind the wheel.”
Mr. Edmonds said that tires in general have increased in overall size in the last 15 years and even low-profile tires aren't as “low” as they once were.
“We've seen aspect ratios change, migrate away from the 70- and 75-series tires which were so popular in the '70s and '90s, to tires that are 60, 55 and even 50 (series),” Mr. Edmonds said. “The other difference is the outside diameters of the tires have changes and the width of the tires, so consequently with the aspect ratio being a percentage of the tire width, low profile maybe isn't quite as low as it used to be.”
For better or worse
While the proliferation of low-profile tire models and sizes has led to the availability of some stylish designs, there are some downsides.
The problems start with dealers, as the sidewall stiffness makes dismounting and mounting a more difficult task than larger tire sizes.
“The biggest problem with low-profile (tires) is you usually have to pay extra to get them mounted,” said Darold Schaefer, owner of R&R Tire Shop in Mankato, Minn. “…Outside of bigger towns, you're not even going to get people to mount them half the time.”
Mr. Schaefer said he believes the allure of low-profile tires is “90-percent appearance” and that they have no major benefits outside of improved steering response and looking “cool.”
“The lower the profile tire, the worse the ride you're going to get and the more often you're going to bend the wheel,” he said. “It's harder on your shocks, it's harder on everything, so what's the advantage?”
Low-profile tires, along with the rims they're mounted on, are especially susceptible to damage from various road hazards because there's less air to provide cushion from bumps.
“That tire is the first line of defense for your vehicle with potholes,” Mr. Edmonds said. “One of the things people don't think about is that sidewall is the first piece of a suspension on your vehicle that absorbs bumps in the road, that absorbs a pothole, so it is an important part of your vehicle suspension. It emphasizes the need to maintain your tires and keep your air pressure properly set.”
Mr. Edmonds said when people contact Tire Rack looking to do plus-one and plus-two fitments on their vehicles, “if they live in an area where there are a lot of potholes and it's a vehicle they're going to drive year-round, we will often suggest they do no more than a plus-one fitment because you want to maintain a little more protection for that wheel.”
Mr. Schaefer said he goes so far as to push people toward the other direction, urging them to put smaller wheels on their car when possible. Not long ago, he said, a local college student came into his shop with bent rims three times within a few months after hitting several potholes. He convinced the father to switch to 16-inch wheels from 17-inch ones.
“That was two years ago,” he said. “She's ready to graduate and she hasn't had to come back since. She's still hitting the same chuck holes…. It was less expensive to buy four new wheels and tires than to keep going with the ones that came from the factory.”
Mr. Chung, however, said dealers need to be aware that reducing the wheel size may not always be appropriate.
“Given the mentioned trend of increasing rim diameters, dealers should note that both vehicle design and engineering have also changed to accommodate as best as possible the tradeoffs in using lower-aspect ratio tires,” he said. “A tried and true tire from the past may not be too compatible with the newer generation of cars.”
According to Mr. Edmonds, many of the perceived problems with low-profile designs could be fixed by educating the public on the importance of tire maintenance.
“That's one thing that I would have to say shame on the tire industry, the manufacturers and the dealers,” he said. “We haven't done a good enough job. Care and feeding of those tires goes a long way, and they're probably the most abused part of our vehicles.”