Magazine for the professional tire industry
Issue link: https://mtd.epubxp.com/i/664171
Built for speed ratings? As ultra-high performance tires continue to evolve technologically, so does their defnition W hen is a UHP tire not a UHP tire? When the speed rating doesn't match the tire's perfor- mance level. If that sounds contradictory, or at odds with conventional thinking over the last 10 years, it is. The defnition of an ultra- high performance tire has been anything V-rated and above for a long time. High performance tires are H-rated. That may be about to change, at least on a small scale. The Rubber Manufacturers Association (RMA) is looking at re-defning the high perfor- m a n c e ( H P ) s e g m e n t b y including V-rated tires. That would make Z-, W- and Y-rated tires UHP tires. Z-rated = 149 mph and over. W-rated = up to 169 mph. Y-rated = up to 186 mph. Advancements in tire tech- nology are partly driving the RMA's discussion. Certainly changing a V-rated tire from UHP to HP takes this into account. It doesn't fully solve the problem with any of the speed ratings, however. "But," you ask, "How can a tire that is rated for speeds up to 186 mph not be an ultra- high performance? Why is Y not good enough?" Rick Brennan, vice president of marketing for Sumitomo Rubber North America Inc., has the answers. It's all about perspective. "If you use the traditional speed rating defnition, then W and Y are UHP. When you look at the actual performance of the tire, you can make a Y-rated tire that has 80,000 miles on it." In reality, a Y-rated tire with an 80,000-mile warranty on it makes it a standard, everyday touring tire, not a UHP tire, he says. It's ultimately about the tire's performance, not the speed rating. Here's literally an extreme example. Apollo Vredestein Tires Inc. markets the Wintrac xtreme S as an ultra-high perfor- mance winter tire. Available in 20 Y-rated sizes ranging from 225/45R18 95Y to 295/30R22 103Y, it is "suitable for the highest performance and most exclusive cars." To summarize, the Y-rated Wintrac xtreme S is available in UHP sizes and designed for high performance vehicles. Is it a UHP tire? No. The Wintrac xtreme S was developed "to stand up to the extreme weather conditions in the coldest season of the year." It is a winter tire. Or more specifcally, a UHP winter tire. "Now that UHP is morphing into different types of segments, you can categorize the perfor- mance level differently," says Brennan. "In essence, that is what we are doing. You can't use speed rating anymore." Maybe not in practice, but speed ratings remain the most objective way to defne a UHP tire. It is nearly impossible to also take into account the tire's performance capabilities, usage, and original equipment ftments when trying to create an apples-to-apples defnition. And what if the tire company defnes the tire as UHP despite evidence to the contrary? Should how the tire is marketed make a difference? That is why Modern Tire Dealer has always defned high and ultra-high performance tires in the traditional way. Otherwise, trending wouldn't be possible. Someday, perhaps in the near future, definitions based on speed ratings really will have little value when it comes to determining market and brand share. When that happens, we will re-defne UHP and HP and start over. It's not like it hasn't happened before. Some, if not all, of the tires on the muscle cars of yesteryear would be lucky to qualify as even cosmetic perfor- mance tires today. — Bob Ulrich If you have any questions or comments, please email me at bob.ulrich@bobit.com. The Wintrac xtreme S is available in 20 Y-rated sizes (96 in all). But it's more a winter tire than a UHP summer tire. 4 Editorial