CR's tests reveal consumers can save gas with the right tires
YONKERS, N.Y., Oct. 6 /PRNewswire-USNewswire/ -- Consumer Reports' latest tests of 34 all-season and all-terrain SUV and pickup truck tires (plus four winter tires) revealed big differences in all-weather performance, tread life, and even fuel economy.
The General Grabber HTS, $105, earned the top spot among all-season tires and the Pirelli Scorpion ATR, $163, rated highest among all-terrain tires, based primarily on impressive grip in dry and wet conditions. (Prices vary depending on the retailer, location and tire size.)
In addition, the Michelin Latitude X-Ice, $128, was top rated among the 4 winter tires CR tested, delivering excellent snow traction and very good grip on ice while keeping tire noise low.
All tire models were tested in a size, (P)265/70R17, commonly used on trucks. CR experts expect that most results will be comparable for other sizes of these models. Tests were performed on a 2007 Chevrolet Silveradopickup and a 2007 Chevrolet Suburban.
Most of the all-season tires CR tested performed very well in braking, handling, and hydroplaning resistance. The tires produced a wide range of tread life and rolling-resistance ratings. But the fact that a number of all-season models with very good tread-life ratings ranked near the bottom in overall performance, shows that it's necessary to look at the big picture when choosing tires.
"The best choice of tires for your SUV or pickup truck depends on its design and how you use the vehicle," said Rik Paul, automotive editor, Consumer Reports. "First, look for tires that provide overall good performance, first, and then use tread life and rolling resistance as tiebreakers, if necessary."
The full tire ratings are featured in the November issue of Consumer Reports, on sale October 7 and online at www.ConsumerReports.org.
Save gas with the right rubber
The tires drivers choose can affect fuel economy. That's because different models have varying degrees of rolling resistance, a measurement of how much energy it takes to roll a tire down a road. According to government estimates, a tire's rolling resistance accounts for about 5 percent of the fuel a vehicle consumes.
To show how rolling resistance affects gas mileage, CR used the Chevrolet Silverado test truck to measure the highway fuel economy of the tires with the best and worst rolling resistance. The Silverado got 2.4 mpg better highway mileage with the Goodyear Wrangler SR-A all-season tire (with the lowest rolling resistance) than with the General Grabber AT 2 all-terrain tire (with the highest rolling resistance). That is a difference of about $300 per year, assuming gas costs $4 a gallon and the car is driven 12,000 miles per year.
All-season vs. all-terrain
All-season tires, like those found on passenger cars, are designed to wear well and to provide good performance under a variety of road and weather conditions. All-terrain tires generally have a deeper, more open tread pattern than all-season tires for off-road grip.
Many all-terrain tires scored lower in handling and rolling resistance than the all-season models. But they also have impressive hydroplaning resistance. Some all-terrain models are designed with a focus on off-road grip, which can compromise their on-road performance. Consumer Reports rated only on-road performance, however, because most vehicles that use these tires are driven mainly on pavement.
For the first time, CR included tread-life ratings for all-season and all-terrain truck tires. These indicate a models' wear potential, as evaluated on a 16,000-mile test conducted at an outside lab. Results show that the fastest-wearing models are predicted to wear out at about 40,000 miles; those with the best wear potential will last for almost 90,000 miles.
CR also reports examples where the real-world results didn't match the manufacturer warranties or the tread wear ratings on the tire sidewalls. Several tires with relatively long tread wear warranties and high government ratings wore quickly in CR's tests.
One example is the BF Goodrich Rugged Trail T/A, which had the longest tread life in the all-season group but had the lowest government tread-wear rating and no tread-wear warranty. It also ranked near the bottom in terms of overall performance.
NOVEMBER 2008
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