Plus-sizing of tires-done primarily to improve the appearance of a vehicle-probably will continue in the future, and that's good news for tire makers.
What began as a niche market in the 1960s has grown to become an important profit center for every tire manufacturer, according to Guy S. Edington, managing director of Kumho Tire U.S.A. Inc.'s Fairlawn, Ohio, technical center.
Mr. Edington talked about the history and future of plus-sizing during a presentation at the International Tire Exhibition and Conference held recently in Akron.
The plus-sizing concept involves increasing the wheel diameter and tire width for appearance, Mr. Edington said. But the idea is really about the wheels because generally they're providing the aesthetic improvement.
The concept also involves maintaining the outside diameter of the tire to minimize any potential issues with the antilock braking system, the speedometer or the odometer, Mr. Edington said.
Over the past couple of decades, plus-sizing has gone hand-in-hand with consumers' desires for performance tires and more powerful cars such as high-performance sedans and sport-utility vehicles, Mr. Edington said. Wheel diameters increased ``exponentially'' during the time, rising to 20-plus inch sizes from 16 inches, he said.
More recently, some SUV rim diameters have grown to 26 inches from 20 inches. Kumho even has a 28-inch concept tire for the Hummer H2 vehicle, Mr. Edington said.
The feeling of ``bigger is better'' won't change in the near future, he said. Issues such as vehicle design, liability and legal requirements will infringe slightly on the market, but the consumer belief that individuality of their vehicle is a right will prevent any excessive regulation, Mr. Edington said.
Original equipment tire and wheel diameters within the passenger segment overall still are growing, and therefore the potential for plus-sizing is increasing as well. While 21-inch tires are now common on concept vehicles, plus-size passenger wheels eventually will reach 22 inches, he said.
For SUVs and light trucks, wheel size growth will stop around 26 inches because of practical vehicle size limitations, Mr. Edington said. But the tire width will continue to grow to more than 350 mm, and practical 24-inch tires and wheels will become available, he added.