September 16, 2011
All vehicles consume energy as they drive. And as efficient as many of them have become, the reality of the internal combustion engine is that much of the energy it uses is lost in the form of heat that doesn't generate any propulsion to move you down the road. Your tires play a much smaller, but also important, role in the fuel consumption equation. Tires resist rolling because of the natural viscoelastic properties of rubber and because the tire's internal components must be forced to constantly stretch and rebound (deflect) as the tire rolls along. The final contributor to tire rolling resistance is the tread's interaction with the road.
Most vehicle manufacturers have been using tires with an emphasis on low rolling resistance as Original Equipment for some time now in an effort to squeeze every bit of fuel efficiency from their vehicles. In contrast, most non-O.E. tire designs haven't placed quite as much focus on low rolling resistance in favor of delivering other attributes consumers ask for, such as better wet traction, or longer tread life, etc. But today's ever-growing consumer interest in being more energy efficient and eco-friendly has some drivers asking for replacement tires that put additional emphasis on improvements in rolling resistance. As a result, more tire lines are being developed with this in mind.
Even though crossovers and SUVs may not be the most efficient vehicles on the road, their fuel efficiency can benefit from riding on more efficient tires. The Tire Rack team evaluated three of the newest energy efficient tire designs for these popular vehicles, comparing the Bridgestone Dueler H/L 422 Ecopia, Continental CrossContact LX20 with EcoPlus Technology and Goodyear Assurance CS Fuel Max. All three feature the manufacturer's latest tread compound and internal design technology to minimize rolling resistance while also maintaining appropriate levels of traction and road manners. Our evaluation used 2009 Porsche Cayenne V6s fitted with new, full tread depth 255/55R18 tires mounted on 18x8.0" wheels.
Our 6.6-mile loop of expressway, state highway and county roads provides a great variety of road conditions that include city and highway speeds, smooth and coarse concrete, as well as new and patched asphalt. This route allows our team to experience noise comfort, ride quality and everyday handling, just as you would during your drive to school or work.
Out on the road the ride quality of the Bridgestone Dueler H/L 422 Ecopia received good marks for comfort from our team. Very close was the Continental CrossContact LX20 with EcoPlus Technology with a similar but slightly firmer ride quality. Rounding out the group was the Goodyear Assurance CS Fuel Max, which felt a little softer than the others but also displayed a small amount of jounce and jiggle after encountering rougher pavement.
All three tires produced minimal tread noise, with the slight advantage going to the CrossContact LX20, and the Dueler H/L 422 Ecopia right behind. The Assurance CS Fuel Max generated just a little more tread noise, but was by no means loud or objectionable.
When it came to everyday light handling the CrossContact LX20 showed a strong advantage over the others with near-instant steering response. The Dueler H/L Ecopia 422 didn't respond quite as quickly, but displayed direct response and a linear feel to steering inputs. The Assurance CS Fuel Max felt very appropriate on our SUV test vehicle, but couldn't match the steering response of the CrossContact LX20 or Dueler H/L 422 Ecopia.
Our 1/3-mile per lap test track course includes 90-degree street corners, a 5-cone slalom and simulated expressway ramps. Run in both dry and wet conditions, the test track allows our team to experience the traction, responsiveness, handling and drivability normally only encountered during abrupt emergency avoidance maneuvers or competition events.
In dry conditions the CrossContact LX20 brought its sporty handling found on the road, displaying crisp handling and good stability during abrupt maneuvers on our course. The Assurance CS Fuel Max followed with noticeably slower steering response, but sufficient overall traction to stay close to the CrossContact LX20. The Dueler H/L 422 Alenza felt very balanced and poised, but didn't have quite the ultimate grip to match the pace of the others.
In the wet the CrossContact LX20 showed its real strength with significantly more overall traction than the other two. The Dueler H/L 422 Ecopia again showed a balanced design that inspired confidence, albeit at a lower traction level than the CrossContact LX20. The Assurance CS Fuel Max trailed somewhat with slower steering response and noticeably less grip.
Our Real World Road Ride features a relatively flat 6.6-mile loop of 65 mph expressway, 55 mph state highway and 40 mph county roads along with two stop signs and one traffic light every lap. Our team drove approximately 500 miles over the course of several days. Since we wanted to compare fuel consumption results that typical drivers would experience, our drivers were instructed to maintain the flow of traffic by running at the posted speed limits and sustain the vehicle's speed using cruise control whenever possible. They did not use hypermiling techniques to influence vehicle fuel economy.
@ 15,000 Miles
|% vs. Most Efficient|
|Bridgestone Dueler H/L 422 Ecopia||19.1||785.3||--|
|Continental CrossContact LX20 with EcoPlus Technology||18.3||819.7||-4.4%|
|Goodyear Assurance CS Fuel Max||19.1||785.3||--|
|*Our evaluation used Linear Logic ScanGauge II automotive computers to record fuel consumption and Race Technology DL1 data loggers to record true distance travelled.|
While all three tires in our test were designed with low rolling resistance as a high priority, we did find a difference in observed vehicle fuel economy. Based on our results, the 0.8 mile per gallon difference between our lowest and highest observed fuel economy would result in an annual difference of about 34 gallons of premium gasoline in our SUV test vehicles. At the current cost of $4.00/gallon, it would amount to an annual difference of about $137 for drivers traveling 15,000 miles a year.
It's important to note our test's fuel consumption measurements follow consistent procedures designed to minimize variables that could influence the results, however they do not represent an exhaustive long-range fuel consumption study. While our procedures require the test vehicles in each convoy to run under the same prevailing conditions, the week-to-week differences in ambient temperatures, barometric pressures and wind speeds that we experience over a season of testing can influence vehicle fuel consumption and prevent the absolute mpg values of this test from being compared directly against those of others.
Larger differences in consumption between tires may indicate a difference that might be experienced on the road, while smaller differences should be considered equivalent. As they say, your mileage may vary.
Winter weather is often unpredictable, and road conditions can change so fast that it's hard to know what waits for you around the next corner. For consistency, our snow testing is done at a dedicated winter test facility in Northern Sweden, and ice testing is done at a local hockey rink to simulate the glare ice often found at intersections and in other high-traffic areas. We measure each tire's ability to accelerate and brake in both conditions, as well as gather subjective ratings of how each tire feels from the driver's seat while driving through several inches of groomed snow on a handling course.
The Dueler H/L 422 Ecopia displayed a measurable advantage in overall snow traction with good balance and predictable handling. The Goodyear Assurance CS Fuel Max followed with reasonable traction, but also a narrower window in which to work at its optimum level. Rounding out the trio is the Continental CrossContact LX20 with EcoPlus Technology that was fairly easy to control, but showed somewhat lower overall traction than the other two.
Several of the tires in our test were able to produce the best observed fuel consumption ratings we've seen to date from our Porsche Cayenne test vehicles. But when viewed in the context of the whole performance envelope these tires seem to have a few tradeoffs in the process.
The Bridgestone Dueler H/L 422 Ecopia and Goodyear Assurance CS Fuel Max both deliver on the promise of good MPG, and consumed the least amount of fuel during our test. But they also give up a little traction to get there. The Continental CrossContact LX20 offers excellent wet and dry traction while trading off a little fuel efficiency versus the most efficient tires we tested.
Bridgestone Dueler H/L 422 Ecopia (Crossover/SUV Touring All-Season): The Dueler H/L 422 Ecopia is one of Bridgestone's ecologically oriented Crossover/SUV Touring All-Season tires developed for the drivers of small- and medium-sized crossover and sport utility vehicles looking to combine year-round traction, handling and comfort with reduced environmental impact. Dueler H/L 422 Ecopia tires are designed to enhance vehicle fuel economy by reducing tire rolling resistance along with the vehicle's carbon dioxide (CO2) emissions while delivering year-round all-season traction, even in light snow. Read more.
Continental CrossContact LX20 with EcoPlus Technology (Crossover/SUV Touring All-Season): The CrossContact LX20 with EcoPlus Technology is Continental Tire's ecologically friendly Crossover/SUV Touring All-Season tire developed to help crossovers, sport utility vehicles and light-duty pickup trucks perform on the highway and in mild off-road conditions. The CrossContact LX20 is designed to enhance driving pleasure, save fuel and maintain grip when braking on wet surfaces while providing long wear and all-season traction, even in light snow. Read more.
Goodyear Assurance CS Fuel Max (Crossover/SUV Touring All-Season): The Assurance CS Fuel Max is Goodyear's Crossover/SUV Touring All-Season light truck tire developed for the drivers of crossover, sport utility vehicles and light duty pickup trucks looking for tires that offer long wear, wet traction and low rolling resistance as some of their top priorities. The Assurance CS Fuel Max is designed to provide year-round, all-season traction in dry, wet and wintry weather conditions, including light snow, as well as offer reduced rolling resistance to enhance vehicle fuel economy over the tire's lifetime. Read more.
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