UHP sizing: Manufacturers speak out
The definition of an ultra-high performance tire continues to evolve, in part due to the demands from original equipment manufacturers. You know what that means: more SKUs.
Can we expect this proliferation to continue? And what exactly are the changes? Are section widths getting wider? Are aspect ratios getting smaller?
We asked a number of tire manufacturers what they are seeing at the original equipment level, which will affect the aftermarket down the road. They are not all in agreement.
Rick Brennan, executive director of product strategy, Falken Tire Corp.: We’re seeing a lot more sizes such as 215/40R18 and 225/40R19 showing up in bigger volumes because you’ve still got the evolution of the small car. Sizes are still evolving to larger rim diameters for cosmetic purposes depending on what type of car it is. Proliferation has happened for the most part and we’re not seeing anything crazy show up any more.
Robert Saul, consumer tire product manager, Bridgestone Americas Tire Operations LLC: Not really — tire sizing has stabilized for now.
Bob Liu, product manager, performance tires, passenger and LT, Continental Tire the Americas LLC: Yes, tire sizes are still getting larger at OE, mainly due to styling. Most concept cars have extremely large diameter rims to increase the design appeal. Another factor is that vehicles are becoming more powerful, requiring more powerful brake systems that are usually larger in size, which require larger rim diameters to clear the brake components.
Scott Jamieson, director of product management, Cooper Tire & Rubber Co.: UHP sizes seem to have stabilized at the OE level. The majority of fitments are still in the 17- to 19-inch range; however there are a growing number of 20-inch fitments.
David Shelton, director of product marketing, GITI Tire (USA) Ltd.: Every year there are more new and larger sizes than what already exist in the market. Design and appearance are the first principles driving the sizing, with a follow-up of gearing, revs per mile, aspect ratio, and air cavity (load carrying). The average size has been growing for the past decade. There should be a maximum envelope, though every year there is something new. Advancements in styling and technology keep driving us forward.
Goodyear Tire & Rubber Co.: We do not see the UHP tire segment going backwards to smaller rim diameters and lower speed ratings. What is becoming apparent is that the extreme outer edge of UHP tires — those in the range of 24-inch diameters and above — is drying up. The sweet spot for UHP tires continues to be 17- to 20-inch sizes, and projections show this to still be the case going forward, especially driven by OE.
John Mosby, product planning coordinator, Kumho Tire U.S.A. Inc.: You’re still seeing a bit of an increase on width on some applications, but we’re not seeing much in the way of wheel diameters increasing; 17- to 19-inch seems to be where they are currently topping out, with some high-end vehicles using 20-inch.
Scott Slemmons, senior sales representative, Maxxis International: Yes, it’s being driven by consumer demand and improved technology by tire manufacturers that has the capability of producing these larger sizes and putting out a quality product.
Jim Knowles, original equipment expert, Michelin North America Inc.: Not necessarily. There are limits to vehicle design that restrict tire size, and OEMs have found that larger tires aren’t always better for the overall balance of performances.
Stephen Ewing, business intelligence manager, Pirelli Tire LLC: More and more vehicles are coming with large rim diameter tires, so the number of new vehicles on 18-inch+ fitments is increasing. However, rim diameters seem to have capped out at 22 inches. Consumers like the look of larger rims ,but they also don’t want to sacrifice ride comfort. OEMs have found the sweet spot between the two with the current 17- to 22-inch size range, depending on the size of the vehicle.
Maxwell Wee, director of sales, Sentury Tire Americas: The trend is for bigger sizes. Cars are getting bigger in response to safety regulations. Bigger and heavier cars need bigger brakes. Bigger diameter wheels are needed to fit over the bigger brakes.
Robert Abram, product planning manager at Yokohama Tire Corp.: Yes and no. While the diameters used at OE generally top out at 21-inch and 22-inch for SUVs (save for special models and exotics), there is still a rise in the usage of 18- to 20-inch fitments, so the overall picture is still showing larger diameters. The simple answer to why is that the USA likes big wheels and a more attractive auto is a sellable auto. ■