Consumer Reports rates General, Pirelli tires best in show
Throughout the course of the year, Consumer Reports tested 34 all-season and all-terrain SUV and pickup truck tires -- plus four winter tires. The results appear in CR's November issue.
The comparison tests revealed big differences in all-weather performance, tread life, and even fuel economy. They also differed in price, although the magazine pointed out that prices vary depending on the retailer, location and tire size.
The big winners were the General Grabber HTS and the Pirelli Scorpion ATR. The Michelin Latitude X-Ice ($128) was top rated among the small sample of winter tires tested.
All tire models were tested in a size (P265/70R17) commonly used on trucks. Tests were performed on a 2007 Chevrolet Silverado pickup and a 2007 Chevrolet Suburban.
The General Grabber HTS ($105) earned the top spot among all-season tires.
Most of the all-season tires tested by CR performed very well in braking, handling and hydroplaning resistance. The tires also produced a wide range of tread life and rolling-resistance ratings.
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," says Automotive Editor Rik Paul.
"First, look for tires that provide overall good performance, and then use tread life and rolling resistance as tiebreakers, if necessary."
In second place was the Continental CrossContact LX ($108), followed, in order, by the Kumho Road Venture APT Kl51 ($104) and the Cooper Discoverer CTS ($159).
Low rolling resistance
The tires consumers 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% 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, which had the lowest rolling resistance among the tires tested, than with the General Grabber AT 2 all-terrain tire, which had 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 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.
Not surprisingly, many all-terrain tires scored lower in handling and rolling resistance than the all-season models in over-the-road testing. But they also have impressive hydroplaning resistance.
(CR rated only on-road performance because most vehicles that use these tires are driven mainly on pavement.)
The Pirelli Scorpion ATR ($163) rated highest among all-terrain tires, based primarily on "impressive grip in dry and wet conditions." In second was the Yokohama Geolander A/T-S ($118), followed, in order, by the Bridgestone Dueler A/T Revo ($143) and the Michelin LTX A/T 2 ($158).
For the first time, CR included tread-life ratings for all-season and all-terrain truck tires. These indicate a model's 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 of where its testing 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 BFGoodrich Rugged Trail T/A, which had the longest tread life in the all-season group according to CR's testing, but the lowest government tread-wear rating and no tread-wear warranty.
The full tire ratings also are featured online at www.ConsumerReports.org.