CONSUMER REPORTS RATES FALKEN, MICHELIN, PIRELLI AND NITTO MODELS BEST IN TESTS OF SUMMER & ALL-SEASON, ULTRA-HIGH PERFORMANCE TIRES
CR says to start shopping for replacement tires before they are worn to the legal limit
YONKERS, NY Consumer Reports rated the Michelin Pilot Sport PPS2 and Pirelli P-Zero best overall in tests of 21 different ultra-high performance summer tires for the November issue, with both models achieving Excellent scores.
Consumer Reports also tested a group of 15 different all-season, ultra-high performance tires for the same issue. In that group, CR rated the Falken Ziex ZE-912 and Nitto Neo Gen ZR best overallagain with Excellent scores.
The Michelin Pilot Sport PS2 achieved an overall score of 85 points in Consumer Reports testing, barely outpointing the Pirelli P-Zero. Both tires provide stellar dry and wet grip and handling. The Michelin had a slight edge in CR tests for hydroplaning resistance while the Pirelli had an edge in dry and wet handling.
There was a near-tie, too, in CR tests of the all-season ultra-high performance tires. A fraction of a point separates the Falken Ziex ZE-912 from the Nitto Neo Gen ZR. After scores were rounded, both finished with 85 points overall. The Falken and the Nitto offered impressive wet and dry braking. While only fair in snow, these all-season tires still are far better on wintry roads than those models made specifically for summer use.
Full tests and ratings of the ultra-high performance tires appear in the November issue of Consumer Reports, on sale now. The complete report is also available to subscribers at www.ConsumerReports.org .
Also known simply as UHP tires, these ultra-high performance models make up a small but important segment of the market. UHP tires are designed to offer tenacious grip and superior handling. Once found only on high-end sports cars, they are now on a wider variety of cars, including sports sedans and more-affordable sports cars. For instance, the Mazdaspeed3 and Saturn Sky recently tested by Consumer Reports were shod with UHP tires.
UHP tires are Z-rated, meaning that they're capable of sustained speeds of 150 mph or more, and they often come in wheel diameters of 17 inches and up. As a trade-off for grip and handling, these high-end tires can be hard-riding and quick-wearing. The summer tires are not designed for use on snow or ice.
Prices for the summer- and all-season UHP tires ranged from $80 to more than $200 apiece for the very popular 225/40ZR18 size that Consumer Reports tested.
Consumer Reports' overall scores are a weighted average for both summer and all-season UHP models emphasizing safety-related characteristics such as braking, handling, and resistance to hydroplaningwhere standing water causes tires to lift off the road surface, leading to a loss of grip and steering control. For all-season UHP tires, snow traction and braking on ice are also key factors.
Noise, comfort and rolling resistance, which relates to fuel economy, were also factored into the scores. Consumer Reports hired a contract laboratory in Texas to conduct tread-wear testing on a government-designed tread wear course; the road circuit is designed to mimic both city and highway driving.
Most summer UHP tires handled the important challenges on wet and dry roads very well. The all-season UHP models gave up a little performance in return for better capabilities in wintry conditions. Consumer Reports' engineers found wide variations among the different performance categories, such as handling, braking, and noise, so there's plenty of room for the consumer to choose a tire tailored to individual preferences.
When to Replace Your Vehicle's Tires
In addition to its ratings of UHP tires, Consumer Reports engineers looked at the issue of when drivers should consider replacing their vehicle's tires. Tires are legally "worn out" when their tread depth reaches one-sixteenth of an inch. "Tread wear indicator bars" molded into the tire visually show consumers when their tires have worn down to that depth.
But Consumer Reports' tests have shown that, for safety sake, consumers should replace their tires soonerwhen they have worn to one-eighth of an inch.
Performance in wet-braking, wet cornering, and hydroplaning resistance tests all dropped off significantly for very worn tires. Replacing tires before they have worn down to the tread wear indicator bars would provide an added safety margin for drivers.
To get a handle on how much tread depth makes a difference, Consumer Reports tested two models of V-rated performance all-season tiresa kind widely available on new cars. CR subjected sets with full tread depth, one-eighth-inch tread depth and one-sixteenth-inch tread depth to a battery of performance tests. (Tires were shaved by a machine to simulate a worn condition so the effects of tire aging could not be taken into account.)
Handling, cornering and dry braking actually improves a bit as tires begin to wear. But hydroplaning resistance and traction on snow deteriorates as tread depth is lost. By the time only one-sixteenth of an inch of tread was left, performance in wet-pavement cornering and braking tests had also deteriorated.
It's also possible to use a coin to measure tread depth. If you don't have a tread depth gauge, you could hold a penny upside down in the tread. Under the old standard, if the top of Lincoln's head on the penny was visible, the tires were worn to one-sixteenth of an inch and you needed new ones.
Consumer Reports engineers are now recommending that you measure for one-eighth of an inch of tread depth, using a quarter rather than a penny. The distance from the coin's rim to George Washington's hairline is about one-eighth inch. If you see George's head, consider replacing your tires.
Consumer Reports is one of the most trusted sources for information and advice on consumer products and services. It conducts the most comprehensive auto-test program of any U.S. publication or Website; the magazines auto engineers and editors have decades of experience in driving, testing, and reporting on cars. To subscribe to Consumer Reports, call 1-800-234-1645. Information and articles from the magazine can be accessed online at http://www.ConsumerReports.org .
Consumers Union 2007
