It's not all that often that SUvs pop up on this site and even less often that one weighing in at nearly three tons graces our pages. Truth is, we rarely have reason to write about these gargantuans. Why? The answer is simple, they aren't usually what we would call green (yes, yes, we know the whole gallons per mile thing). Every once in awhile we feel bad for overlooking some of the green advancements that many SUVs have made in recent years and self-pity drives us to write up something about these behemoths and call it a day. That time has come again.
Chevy has made a few aero enhancements to the Tahoe that decreases its coefficient of drag to a best-in-class 0.379. According to General Motors, the next closest competitor to the Tahoe only manages a Cd of 0.404 and the average for all of the Tahoe's competitors comes in at 0.416. With best-in-class drag numbers, Chevy has managed to improve efficiency from the 2009 Tahoe ratings of 14 miles per gallon city and 19 mpg highway up to the 2010/11 numbers of 15 mpg city and 21 mpg highway. The improvement may sound minor, but every little bit helps. If you're in the market for a big SUV and want to get more miles per gallon, the Chevy Tahoe Hybrid offers 21 mpg city and 22 mpg highway with an even-lower-yet Cd of 0.360. By tweaking the exterior of the Tahoe and dropping the draggy appearance, General Motors has shown that a mere cosmetic makeover can make a difference in fuel economy. Follow the jump for more info on the aerodynamic benefits of the 2010/11 Chevy Tahoe.
[Source: General Motors}
Want more miles to a gallon of fuel? One way to go farther is through efficient vehicle design and a low coefficient of drag or CD. When it comes to full-size SUVs that slip most easily through the air, look no further than the Chevrolet Tahoe.
The aerodynamic design of the 2010 and 2011 Tahoe results in a segment-leading CD of 0.379. The next closest vehicle in the segment has a rating of 0.404 and the average for all competitors is 0.416.
"For owners, the Tahoe's aerodynamic advantage means fewer fill-ups, and more miles per gallon," said Greg Fadler, GM aerodynamics engineering group manager. "We estimate the Tahoe delivers over an extra mile per gallon at highway speeds as compared to the average coefficient of drag for full-size SUVs."
A vehicle's drag coefficient or "CD" is a rating of the vehicle's aerodynamic shape efficiency. The lower the number the less resistance the vehicle shape has to the air. Key design features helping the Chevrolet Tahoe slip through the air include a shaped airdam, one-piece front fascia and low drag outside side-view mirrors.
"We constantly provide data to our exterior designers that shows what changes in design have on aerodynamic forces," said Fadler. "It comes down to fine-tuning shapes for every possible thousandth gain in CD while still allowing for compelling overall design."
At highway speeds aerodynamics have the largest impact on fuel consumption. Aerodynamic drag accounts for approximately 30 to 40 percent of mechanical work energy an SUV on the highway, directly impacting vehicle fuel efficiency.
The importance of low-resistance design is illustrated by the fact that it takes 20 percent more fuel to overcome aerodynamic drag at 70 mph than 60 mph.
The 2010 Tahoe, which seats up to nine, offers EPA-estimated city/highway mpg of 15/21 (2WD and 4WD models). The Chevrolet Tahoe Hybrid has an even better CD rating of 0.360 and features EPA-estimated fuel economy of 21 mpg city and 22 mpg highway.