Mr. Green Car: Tesla S sedan — a test drive, part two: the chassis
Editor’s note: Part one of this series appeared in the Dec. 3-9, 2014, issue.
By Allen Penticoff
Well, I’ve yet to win the lottery so I can own a Tesla Model S, but I’d write this column whether I did or not, since I enjoy writing about this wonderful car. You’re thinking, “Yeah, yeah, Allen, Tesla … blah blah blah — oh so wonderful. Really?”
Before I get into chassis details, which may be rather boring, let me start with an astounding bit of information. The 2014 Tesla Model S earned Consumer Reports’ (a very impartial evaluation) Best Overall Automobile across 10 categories.
The following was found on Wikipedia: “Consumer Reports gave the Model S a score of 99 out of 100, it’s highest ever. The score would have been higher except that it does need to stop to recharge during long-distance drives. ‘If it could recharge in any gas station in three minutes, this car would score about 110,’ said Jake Fisher, head of auto testing for Consumer Reports. Fisher called the car’s performance in the magazine’s performance tests ‘off the charts.’ Consumer Reports’ 2013 survey of owner satisfaction produced a score of 99 out of 100, ‘the highest the magazine has seen in years.’ In 2014, the Model S topped for the second year in a row Consumer Reports’ survey of owner satisfaction. This time, the Model S had a score of 98 out of 100. Consumer Reports found the Model S to be the ‘Best Overall’ for 2014 across all 10 categories of cars, light trucks and SUVs, chosen from more than 260 vehicles the organization has recently tested. The magazine considers the Model S a ‘technological tour de force, while pricey, is brimming with innovation.’”
In addition to the many awards it has received, there are three other points of pride. Tesla’s assembly facility is in Fremont, California, with 50 percent domestic content, including the motor and transmission. It is perhaps the most aerodynamic production car ever, and has maxed out the safety ratings — although Tesla’s claim to be the safest car ever has been disputed, nobody denies it is very safe indeed.
Styled by Franz von Holzhausen and built of all aluminum construction, the chassis is very lightweight and corrosion resistant. In a road salt-free environment like California, where many of the nearly 50,000 (worldwide) Teslas reside, the chassis will last nearly forever with proper care. After a couple of small battery fires as a result of road debris penetrating the quarter-inch steel shield protecting the battery pack under the car — all have been (or will be at next service) upgraded to new titanium/aluminum shielding and slightly higher ground clearance at highway speed (more on this in a moment). The battery packs are compartmentalized into 10 areas that have fire-resistant material, limiting the spread of any fire through the battery pack. In any case, the batteries are far less dangerous than a tank of gasoline, and therefore much safer. No Tesla Model S has been destroyed by fire that I am aware of.
Additional safety features include heavier rear bumpers when the rear-facing child seat option is purchased. Interestingly, Tesla has not gone overboard on air bags. There are eight — by no means the most to be found in a production car — but since its safety ratings are maxed out, apparently these are adequate. If the air bags do deploy, the main drive battery pack is automatically disconnected. Teslas come equipped with top-end Brembo disc brakes at all wheels. However, regenerative braking is quite pronounced, such that the brake lights will illuminate when you lift your foot off the accelerator pedal — the brake pads may well last 100,000 miles. But if you need to stop in a hurry, the brakes are very powerful.
In a standard rear-wheel drive version, the single drive motor resides behind the rear seat. In the all-wheel drive “D” versions, another motor is between the front wheels. None of this intrudes into the passenger cabin. The lithium-ion battery pack is mounted entirely under the car. In theory, it could be swapped for a fully charged battery pack in 90 seconds if such service becomes available in the future. At present, the 480-volt DC Supercharger stations can supply long-distance driving with charge times of 20 to 30 minutes to gain 180 miles of range.
A standard-issue Tesla Model S comes with coil springs; however, a $2,250 option is to add air suspension. In addition to somewhat better ride and handling, the key feature of the air suspension is the ability to lower the chassis closer to the road at highway speeds — improving its already very slippery drag coefficient of 0.24. The lower priced models come with 19-inch wheels; with 21-inch wheels optional (standard on Performance models). Tesla does warn, however, that the 21-inch wheels may be susceptible to road damage and poor inclement weather performance. I, for one, would not use the 21-inch wheels on Illinois’ all-too-often rough roads. All-wheel drive options are available for better poor-weather performance, in addition to the recommended use of winter tires.
As with many new cars, the Tesla Model S has electric power steering. What many yet lack is autopilot capabilities. Beginning in September 2014, all new Model S cars come with sensors that provide a 360-degree buffer zone that allows the car to detect road signs, lane markings, other vehicles and obstacles. Adaptive cruise control allows the car to maintain a set distance from the car in front of you and to stop, as necessary, if suddenly it perceives distance to an object or other vehicle is too close. As part of the expansive $4,250 “Tech Package,” a true autopilot will be available that will allow for hands-free driving. As of this writing, the hardware is installed with this option, but the software has yet to be provided.
Lastly, as winter is already upon us Illinoisans — we would probably sign up for the $750 “Subzero Weather Package” that includes rear heated seats, heated wiper blades and washer nozzles (heated front seats and steering wheel are standard). The cabin heater is a ceramic electric resistance heater (like a space heater) that provides heat instantly, but consumes a lot of power. Our Volt has a similar heater that we use with great reluctance because of its power hungry nature, but with a Tesla’s huge 60 Kwh or 85 Kwh battery pack, you won’t need to stint on heat or air-conditioning.
Next, I’ll report on the exciting acceleration, top speed and range of the Tesla Model S.
From the Dec. 24-30, 2014, issue