August 20, 2010
Tires designed to be eco-friendly were initially offered to drivers of small hybrid or ultra-efficient cars. As the world's focus on being ecologically responsible continued to expand beyond the hybrid community, more "green" tire offerings slowly began to include many everyday passenger cars. This trend has continued into the crossover/SUV market, as vehicle and tire manufacturers recognize the tire's role in helping reduce fuel consumption even on these larger, less efficient vehicles.
We decided to compare several of these eco-friendly crossover/SUV tires in our Real World Road Ride and Performance Track Drive to see how they drive in everyday conditions. Kumho brands the Solus KL21 tire with their eco symbol, which indicates it uses high dispersion silica in the tread compound to improve fuel economy. Anti-abrasion carbon black mixed in helps improve wear resistance while an eco-friendly design helps reduce rubber dust particle emissions as the tire wears. In our test size, the Michelin Latitude Tour HP is an Original Equipment (O.E.) option on our Porsche Cayenne test vehicles. Bearing their Green X label, this tire features a unique shape and special tread compound to aid fuel efficiency, as well as is produced with non-aromatic oils to reduce its environmental impact. The Pirelli Scorpion Verde (verde is Italian for green) All Season features Pirelli's EcoImpact designation highlighting the innovative materials and advanced tread compound used to lower rolling resistance for improved fuel consumption, as well as increase tire wear life. The Scorpion Verde continues its green theme by using Highly Aromatic Oil Free compounds and 8% less raw materials. 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.
All three tires delivered refined levels of ride quality. The Kumho Solus KL21 did a very good job eliminating the small ripples and medium-sized bumps in the road, but became a little jostled when encountering sharper impacts. The Pirelli Scorpion Verde All Season followed closely, also managing to soften many of the bumps in the road. The Michelin Latitude Tour HP provided a tight, controlled ride that also did a good job absorbing the smaller bumps along the route, while larger impacts would find their way to the driver with a bit of a thump.
The Solus KL21 produced the least amount of tread noise and only moderate impact noise when it encountered larger bumps. The Scorpion Verde All Season also did a good job minimizing tread pattern noise, but did produce some moderate boom on larger impacts. The Latitude Tour HP displayed a modest tread growl heard at below highway speeds, along with a bit of a ring when it ran over larger impacts.
When it comes to handling, the firmer ride of the Latitude Tour HP paid back with responsive steering and tight handling. The Scorpion Verde All Season delivered very responsive steering that some of our drivers found bordered on being nervous during straight line driving. The Solus KL21 felt a little sluggish when compared with the other two, reacting a little more slowly to driver inputs.
Our 1/3-mile per lap test track course includes 90-degree street corners, lane changes 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.
Out on the dry track the Michelin Latitude Tour HP felt well tuned for the task (likely why it was chosen as O.E. in the first place), delivering stable handling and confidence-inspiring control during abrupt maneuvers. The Pirelli Scorpion Verde All Season followed close behind, showing the quick steering response found on the road but not having quite the ultimate traction to keep pace with the Michelin. The Kumho Solus KL21 rounded out the group subjectively, feeling a little sluggish to respond to driver inputs.
In the wet, the Latitude Tour HP was able to lap our course the fastest of the group, feeling responsive, sure-footed and stable. Following right behind was the Scorpion Verde All Season, which used its quick steering response and excellent braking traction to nearly match the lap time of the Michelin tire. Trailing somewhat behind was the Solus KL21 that felt a little less responsive than the others and lacked their ultimate cornering traction.
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|
|Kumho Solus KL21||18.3||819.7||--|
|Michelin Latitude Tour HP N1||18.3||819.7||--|
|Pirelli Scorpion Verde All Season||18.2||824.2||-0.55%|
|*Our evaluation used Linear Logic ScanGauge II automotive computers to record fuel consumption, and Race Technology DL1 data loggers to record true distance travelled.|
All three of the tires in this test were designed with low rolling resistance as a priority and we didn't find a significant difference in observed vehicle fuel economy. The 0.1 miles per gallon difference between our lowest and highest recorded fuel economy measurements would result in an annual difference of only 4.5 gallons of premium gasoline at a current cost of about $12.39 (at $2.75/gallon) 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.
Kumho Solus KL21 (Crossover/SUV Touring All-Season): The SOLUS KL21 is Kumho's Crossover/SUV Touring All-Season tire developed for the driver of crossovers, sport utility vehicles and prestigious pickups looking for year-round capabilities. Many of the SOLUS KL21 tires meet Kumho's eco standard for low rolling resistance that confirms the tire's contribution to reducing vehicle fuel consumption and emission of CO2 gases. The Solus KL21 is designed to combine ride comfort and low noise with year-round handling and traction, even in light snow. Read more.
Michelin Latitude Tour HP (Crossover/SUV Touring All-Season): The Latitude Tour HP is Michelin's Crossover/SUV Touring All-Season light truck tire developed for the drivers of premium crossover and sport utility vehicles. Used as Original Equipment by Acura, BMW, Lexus, Porsche and others, Latitude Tour HP tires are designed to combine comfort, handling and all-season traction, even in light snow. Read more.
Pirelli Scorpion Verde All Season (Crossover/SUV Touring All-Season): The Scorpion Verde All Season is Pirelli's eco-friendly Crossover/SUV Touring All-Season tire developed for the drivers of crossovers, sport utility vehicles and prestigious pickups. The Ecoimpact icons on the sidewall of the Scorpion Verde All Season highlight its environmental compatibility where it reduces rolling resistance and tire weight, compared to Pirelli's previous CUV/SUV tire lines, to increase fuel economy and lower the vehicle's CO2 emissions. The Scorpion Verde All Season is designed to combine dry and wet road handling, comfort and year-round capabilities, including all-season traction in light snow. Read more.
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