The SLK is a compact roadster manufactured by Mercedes-Benz in three generations; R170 launched in 1996, the R171 in 2004 and R172 in 2011. As one of the first modern retractable hardtop convertibles, the SLK followed the 1995 Mitsubishi 3000GT Spyder and preceded other retractable hardtops such as the Peugeot 206cc, Lexus SC, Pontiac G6 and the Chrysler Sebring. The SLK Vario-roof was first shown on the SLK II concept car at the 1994 Paris Motor Show. The car went on sale two years later in Europe, and in 1997 in the US. The SLK isbuilt in Bremen, Germany. The designation SLK derives from the company's design mission to create a roadster that was at once sporty, light and short — in German: Sportlich, Leicht und Kurz. The SLK-Class was launched in 1996 on the new R170-platform. The SLK 230 Kompressor launch model was designed to compete with the Porsche Boxster and BMW Z3. Based on the 1994 concept SLK I shown at the Turin Motor Show and the SLK II from the Paris Motor Show, it featured an unusual folding hardtop. It was powered by a 193 hp 2.3 L supercharged I4 engine and a choice of automatic transmission or 5-speed manual transmission. The SLK was a modern incarnation of the 1950s Mercedes-Benz 190SL by returning to four cylinders and a 94-inch (2,400 mm) wheelbase. Massively successful in its first year, worldwide sales hit 55,000, over double the entire nine-year production of 190SLs, and between 1996 and 2004, over 311,000 SLKs were sold. The very first R170 Mercedes SLK was completed on January 29, 1997 and last on April 7, 2004.
The roof design developed by Mercedes-Benz consists of a folding steel hard top which is divided in half along an axis at right angles to the direction of travel. Both halves are linked by a kinematic mechanism which is locked securely when the roof is closed. At the touch of a button on the centre console, a hydraulic system with five cylinders controls the fully automatic folding process in which the boot lid is also integrated. It opens by tipping to the rear so that the two roof halves have sufficient freedom of movement to pivot backwards as the vario-roof opens; the roof sections then position themselves one on top of the other, and disappear into the boot. If the roof is to be closed, the same sequence of movements is performed in reverse order. The hydraulic system stows the vario-roof in the upper section of the boot. A plastic roller blind separates it from the luggage space below, an area with a capacity of 145 litres in the first-generation SLK. With the vario-roof closed, the load volume increased to a substantial 348 litres (12.3 cu ft). Two fixed roll-over bars behind the seats worked with the particularly strong A-pillars to form an integrated system offering a high degree of roll-over protection. In 2000, the SLK received a facelift which included new front and rear bumper designs, body coloured side skirts and the introduction of new wing mirrors incorporating indicators. The range was expanded to include a new entry level model SLK 200 Kompressor and a new V6 in the SLK 320. Technical improvements includes the addition of Electronic Stability Program (ESP) and a new 6-speed manual transmission. A stabilizer bar was added to the rear and they reinforced the front one. A 3.46:1 axle was added for the manual shift SLK. Gas tank grew from 12 to 14 gallons. In 2001 a new AMG model was added, with a 354 hp (264 kW) supercharged version of the 3.2 L V6. This SLK 32 AMG was the best-performing R170 SLK, and was a direct rival of the BMW M Roadster and Porsche Boxster S. It was only offered with the newly engineered five-gear "SpeedShift" and boasted 35% quicker automatic shifts.. All engines were hand-built by AMG by an individual engineer. The SLK32 AMG's engine has twin spark plugs per cylinder for maximum combustion and was fitted with an intercooled Lysholm-type "twin-screw" supercharger. Brakes became 13.15" diameter vs. 11.8" standard. AMG production ran between Aug 2000 and March 2004. Only 4,333 were built in total, of which 979 were retained for Germany, 2,056 exported to the USA and 263 to the UK. In July 2004 a Special Edition was launched prior to the replacement with the new R171 SLK in 2005. The R170 lived on as the Chrysler Crossfire until 2008, sharing substantial elements of the SLK including engines and interiors.
The second generation SLK vehicle was unveiled in 74th Geneva Motor Show in March 2004 with a new body, new engines and new interior. Known by its code name R171, the exterior featured a new Formula One-inspired front design, and also took design cues from the Mercedes-Benz Vision SLA concept car from 2000. For 2005 the SLK was named one of Car and Driver Ten Best and won the Canadian Car of the Year's Best New Convertible award. Models of the new SLK include:* SLK 200 Kompressor - 1.8 L 120 kW (163 PS; 161 hp) I4 supercharged engine, 0–100 km/h (62 mph) 7.9 seconds, top speed of 143 mph. (not available in Canada and the United States)
* SLK 300 (known as SLK 280 in some markets) - 3.0 L (2996 cc) 170 kW (231 PS; 228 hp) double overhead cam V6 engine, 0–100 km/h (62 mph) 6.3 seconds, top speed 155 mph. (starting in 2006 model year)
* SLK 350 - new 3.5 L (3498 cc) 200 kW (272 PS; 268 hp) double overhead cam V6 engine, 0–100 km/h (62 mph) 5.4 seconds, top speed 155 mph (electronically limited).
* SLK 55 AMG - 5.4 L (5439 cc) 265 kW (360 PS; 355 hp) V8 engine, 0–100 km/h (62 mph) 4.9 seconds (officially time), tested speed 4.3 seconds, top speed 155 mph (249 km/h). A tuned version of this was used as the Formula One safety car, replaced by CLK 63 AMG at the beginning of 2006 Season. The SLK55 AMG was the first Mercedes tuned by AMG's Performance Studio to a Black Series model.
Mercedes-Benz announced the new SLK in the autumn of 2010, several months prior to its official 2011 launch, allowing car magazines to drive disguised test cars. The company took the unusual step of issuing several press releases in October and November 2010 announcing new features such as "Magic Sky Control". In January 2011 the car was officially announced.The SLK became a symbol of the brand image with a powerful halo effect and brought new customers to Mercedes-Benz. Some 42 per cent of the drivers in Western Europe who chose the roadster were new Mercedes customers.