Certified Benz & Beemer Compares 2012 BMW 6 SERIES VS 2012 Mercedes E-Class Near Phoenix, AZ

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2012 Mercedes E-Class

Safety Comparison

The 650i offers all wheel drive to maximize traction under poor conditions, especially in ice and snow. The E-Class Cabriolet doesn’t offer all wheel drive.

A passive infrared night vision system optional on the 6 Series helps the driver to more easily detect people, animals or other objects in front of the vehicle at night. Using an infrared camera to detect heat, the system then displays the image on a monitor in the dashboard. The E-Class Cabriolet doesn’t offer a night vision system.

The 6 Series offers an optional Side and Top View Cameras to allow the driver to see objects all around the vehicle on a screen. The E-Class Cabriolet only offers a rear monitor and front and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the sides.

Both the 6 Series and the E-Class Cabriolet have standard driver and passenger frontal airbags, front side-impact airbags, head airbags, front seatbelt pretensioners, plastic fuel tanks, four wheel antilock brakes, traction control and electronic stability systems to prevent skidding.

Warranty Comparison

The 6 Series’ corrosion warranty is 8 years and unlimited miles longer than the E-Class Cabriolet’s (12/unlimited vs. 4/50,000).

BMW pays for scheduled maintenance on the 6 Series for 4 years and 50,000 miles. BMW will pay for oil changes, tire rotation, lubrication and any other scheduled maintenance. Mercedes doesn’t pay scheduled maintenance for the E-Class Cabriolet.

There are over 12 percent more BMW dealers than there are Mercedes dealers, which makes it easier to get service under the 6 Series’ warranty.

Reliability Comparison

To reliably start during all conditions and help handle large electrical loads, the 6 Series has a standard 900 amp battery. The E-Class Cabriolet’s 800 amp battery isn’t as powerful.

The battery on the 6 Series is in the trunk, which protects it from hot underhood temperatures which can degrade battery life. By keeping the 6 Series’ battery 20 to 30 degrees cooler, its life is increased by years. The E-Class Cabriolet’s battery is in the hot engine compartment.

Engine Comparison

The 640i’s standard 3.0 turbo 6 cyl. produces 13 more horsepower (315 vs. 302) and 59 lbs.-ft. more torque (332 vs. 273) than the E350 Cabriolet’s standard 3.5 DOHC V6. The 650i’s standard 4.4 turbo V8 produces 7 lbs.-ft. more torque (450 vs. 443) than the E550 Cabriolet’s standard 4.7 turbo V8.

For more instantaneous acceleration and better engine flexibility in any gear, the 6 Series’ engines produce their peak torque at lower RPM’s than the E-Class Cabriolet:


640i 3.0 turbo 6 cyl.

1400 RPM

650i 4.4 turbo V8

1750 RPM

E350 Cabriolet 3.5 DOHC V6

3500 RPM

E550 Cabriolet 4.7 turbo V8

1800 RPM

Fuel Economy and Range Comparison

On the EPA test cycle the 640i RWD gets better fuel mileage than the E350 Cabriolet (21 city/31 hwy vs. 18 city/28 hwy).

Regenerative brakes improve the 6 Series’ fuel efficiency by converting inertia back into energy instead of wasting it. The E-Class Cabriolet doesn’t offer a regenerative braking system.

In heavy traffic or at stoplights the 6 Series 640i’s engine automatically turns off when the vehicle is stopped, saving fuel and reducing pollution. The engine is automatically restarted when the driver gets ready to move again. (Start/Stop isn’t accounted in present EPA fuel mileage tests.) The E-Class Cabriolet doesn’t offer an automatic engine start/stop system.

The 6 Series has 1.1 gallons more fuel capacity than the E-Class Cabriolet (18.5 vs. 17.4 gallons), for longer range between fill-ups.

Brakes and Stopping Comparison

For better stopping power the 6 Series’ standard brake rotors are larger than those on the E-Class Cabriolet:

6 Series

E-Class Cabriolet

Front Rotors

13.7 inches

12.7 inches

Rear Rotors

13.6 inches

11.8 inches

Tires and Wheels Comparison

For better traction, the 6 Series has larger standard tires than the E-Class Cabriolet (245/40R19 vs. 235/45R17).

The 6 Series’ optional 245/35R20 front and 275/30R20 rear tires provide better handling because they have a lower 35 series front and 30 series rear profile (height to width ratio) that provides a stiffer sidewall than the E550 Cabriolet’s 40 series front and 35 series rear tires.

For better ride, handling and brake cooling the 640i has standard 18 inch wheels. Smaller 17 inch wheels are standard on the E-Class Cabriolet. The 6 Series’ optional 20 inch wheels are larger than the 18 inch wheels on the E550 Cabriolet.

Changing a flat tire near traffic can be dangerous and inconvenient. The run-flat tires standard on the 6 Series can be driven up to 50 miles without any air pressure, allowing you to drive to a service station for a repair. The E-Class Cabriolet doesn’t offer run-flat tires.

Suspension and Handling Comparison

The 6 Series offers an available active suspension system, which counteracts cornering forces actively, limiting body roll and improving handling and stability. Mercedes doesn’t offer an active suspension on the E-Class Cabriolet.

For a smoother ride and more stable handling, the 6 Series’ wheelbase is 3.7 inches longer than on the E-Class Cabriolet (112.4 inches vs. 108.7 inches).

For better handling and stability, the track (width between the wheels) on the 6 Series is 2.5 inches wider in the front and 4.4 inches wider in the rear than on the E-Class Cabriolet.

The 650i Convertible handles at .89 G’s, while the E550 Cabriolet pulls only .87 G’s of cornering force in a Car and Driver skidpad test.

Passenger Space Comparison

The 6 Series Convertible has 9 cubic feet more passenger volume than the E-Class Cabriolet (89 vs. 80).

The 6 Series has 2 inches more front headroom, .1 inches more front legroom, 2.8 inches more front shoulder room, .3 inches more rear headroom, .4 inches more rear legroom and 1.8 inches more rear shoulder room than the E-Class Cabriolet.

Cargo Capacity Comparison

The 6 Series Convertible has a much larger trunk with its top down than the E-Class Cabriolet with its top down (10.6 vs. 8.8 cubic feet). The 6 Series Convertible has a larger trunk with its top up than the E-Class Cabriolet with its top up (12.4 vs. 11.5 cubic feet).

Ergonomics Comparison

The 6 Series offers an optional heads-up display which projects speed and other key instrumentation readouts onto the windshield, allowing drivers to view information without diverting their eyes from the road. The E-Class Cabriolet doesn’t offer a heads-up display.

The 6 Series’ front and rear power windows all open or close with one touch of the switches, making it more convenient at drive-up windows and toll booths, or when talking with someone outside of the car. The E-Class Cabriolet’s rear power window switches have to be held the entire time to close them fully.

Heated windshield washer nozzles are standard on the 6 Series to prevent washer fluid and nozzles from freezing and help continue to keep the windshield clear in sub-freezing temperatures. The E-Class Cabriolet doesn’t offer heated windshield washer nozzles.

The 6 Series has a standard center folding armrest for the rear passengers. A center armrest helps make rear passengers more comfortable. The E-Class Cabriolet doesn’t offer a rear seat center armrest.

Optional BMW Apps for the 6 Series allows the driver and passengers access to select programs on their smartphones, including reading text messages aloud, playing internet radio stations, tagging songs to buy them later, following twitter accounts and other online activities without taking their eyes off the road or their hands from the wheel. The E-Class Cabriolet doesn’t offer factory integrated smartphone program access.

The 6 Series’ optional Parking Assistant can parallel park or back into a parking spot by itself, with the driver only controlling speed with the brake pedal. The E-Class Cabriolet doesn’t offer an automated parking system.

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