Mercedes SLK Technologically Advanced, But Stays True to Roadster Formula

KNOXVILLE, TN – Ah, there’s nothing like driving a German-engineered roadster, wind in your hair, down one of the finest stretches of road this side of the Atlantic.

With 318 turns over 11 miles (18 km), the route dubbed the “Tail of the Dragon” brings out the best in the ’12 Mercedes SLK roadster, which is not the fastest or priciest vehicle in the Mercedes-Benz lineup, but quite possibly the most rewarding to drive.

The SLK’s spot-on steering and handling is reminiscent of a classic British roadster, except with gobs more horsepower. The 3.5L V-6’s 302 hp and 273 lb.-ft. (370 Nm) of torque make for an exhilarating drive as the roadster gobbles up turn after turn with ease.

Key to the SLK’s handling characteristics is its direct-steer rack-and-pinion setup. While many other auto makers have gone to electric steering, Mercedes wisely sticks to the tried and true.

While electric steering saves a bit of fuel, the technology just doesn’t provide the same road feedback as hydraulics, which is critical for a car like the SLK.

However, Mercedes doesn’t completely abandon newer technology in its steering system. The power-assisted rack boasts a variable ratio that provides quick response while at speed and less effort in low-speed situations.

For safety, the steering unit is mounted to the front subframe, which helps absorb crash energy and is designed to slide safely under the passenger compartment in the event of a collision.

The steering configuration is a good match for the suspension setup. McPherson struts with incorporated coil springs up front keep road imperfections from reaching the cabin; a front stabilizer bar, which Mercedes says acts like a torsion bar, minimizes body lean.

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The 5-link independent rear suspension does a good job of minimizing vibration and allows the driver to dial in some understeer, which comes in handy navigating the Dragon, as does the rear-stabilizer bar mounted directly to the body.

Making the drive all the more enjoyable is the superb 7-speed automatic transmission. The SLK350 comes standard with paddle shifters, but they prove unnecessary, as the transmission arguably performs better than any human could while in full-auto mode.

Shifts are quick and nearly imperceptible and never feel like the transmission is hunting for the correct gear.

The drive route here provides an opportunity to test the merits of Mercedes’ “adaptive shifting” technology, which the auto maker claims can “learn” particular driving styles.

The system is supposed to detect speed and throttle changes and automatically make adjustments to eliminate extensive shifts while traveling uphill or downhill. For drivers who primarily travel on highways, the transmission holds gears longer for quicker acceleration, Mercedes says.

Whether the system operates here as intended is tough to tell in the limited seat time we have during testing. That said, the transmission performs flawlessly, so we’ll give Mercedes the benefit of the doubt and credit some of that performance to adaptive shifting.

The aluminum-block 3.5L direct-injected V-6 is a good match for the transmission. With 273 lb.-ft. (4,744 Nm) of torque available at just 3,500 rpm, the engine thrusts the SLK from a dead stop.

The 302 hp created by the mill may seem like overkill for a roadster, but is necessary to adequately power the portly SLK350, which weighs in at nearly 2 tons (1,814 t). Much of the weight comes from the generous amount of bracing, which keeps to a minimum chassis flex, a common problem with droptops.

Still, the SLK’s massive weight is noticeable through the tight corners. Yet the 3.5L V-6 still achieves an admirable fuel-economy rating of 20/29 mpg (11.7-8.1 L/100 km) city/highway.

The sophisticated retractable hardtop mechanism also adds pounds. Six hydraulic cylinders operate the top: two control the roof, two others lock it to the windshield frame and the remaining two power the tubular roof frame.

The mechanism can raise or lower the top in a scant 20 seconds, 2 seconds faster than its predecessor.

While the operating speed is impressive, the amount of trunk space – 6.4 cu.-ft. (181 L) – while the top is folded, is more so. It may not sound like a lot, but it’s more than some other roadsters, including the Audi TT with 6.0 cu.-ft. (170 L).

The interior is typical Mercedes – no-nonsense Teutonic luxury. From the woods to metallic inlays, everything seems just right and is aesthetically pleasing.

If there’s one gripe, it’s that some of the controls are a tad confusing, especially for audio. Selecting a radio station should not be this difficult.

Another flaw, as with all Mercedes, is the placement of the cruise-control stalk on the left side of the steering wheel, near the turn-signal controls. It’s far too easy to activate the cruise control while trying to use the turn signal.

Ward’s recently was told Mercedes brass is aware of the problem and will relocate the cruise control in future models.

The SLK 350’s exterior is more masculine than the outgoing model. Mercedes publicly won’t admit the earlier-generation SLK was too feminine. But it privately acknowledges there was a conscious effort to make the ’12 SLK appealing to both men and women.

The exterior styling takes some cues from iconic Mercedes models of the past, most noticeably the 190SL of the 1950s. The long, swooping front hood evokes true sportiness, lacking on the outgoing model, and the wheels pushed further to the corners gives the car an aggressive stance.

The ’12 SLK350 is one of the most technologically advanced vehicles to come from Mercedes in quite some time.

Some technologies found on the car are common in the luxury class, including bi-xenon headlights, light-emitting-diode taillights and Bluetooth connectivity. But not Mercedes’ patented Air Scarf, which blows warm air on the necks of occupants, making top-down driving in cold weather more comfortable.

The niftiest gadget is the Magic Sky Control, which allows occupants to press a button on the overhead console to change the roof panel from transparent to heavily tinted nearly instantaneously. This is a “surprise-and-delight” feature if there ever was one.

The ’12 Mercedes SLK350 is a solid entry in the luxury-roadster segment, where pickings are relatively slim. Ultimately its greatest appeal will be to those Mercedes loyalists waiting for a roadster with power, handling and a healthy dose of masculinity.

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