Mercedes-Benz SLK (R172) SLK 300 (245 Hp) 9G-TRONIC

Mercedes-Benz SLK (R172) SLK 300 (245 Hp) 9G-TRONIC

The Mercedes-Benz SLK, a name synonymous with compact luxury roadster motoring, saw its third and final generation, the R172, introduced in 2011. Among its various iterations, the Mercedes-Benz SLK (R172) SLK 300 (245 Hp) 9G-TRONIC represented a significant update to the model line, specifically for the 2015-2016 model years. This particular variant was positioned as a compelling blend of performance, efficiency, and classic Mercedes-Benz refinement, offering a distinct open-top driving experience in the premium compact segment. Replacing the SLK 250, the SLK 300 brought a more potent engine and an advanced transmission, enhancing its appeal to enthusiasts seeking a spirited yet comfortable two-seater.

The R172 generation itself built upon the success of its predecessors, retaining the iconic retractable hardtop roof while incorporating design cues from Mercedes-Benz’s larger SLS AMG supercar, lending it a more aggressive and contemporary aesthetic. The SLK 300 variant, with its relatively short production run before the model was facelifted and rebranded as the SLC-Class, stands as a pivotal point in the SLK’s history, showcasing Mercedes-Benz’s commitment to evolving its powertrain technology and maintaining its competitive edge in a niche but highly desirable market segment.

Engine and Performance of the Mercedes-Benz SLK (R172) SLK 300

At the heart of the Mercedes-Benz SLK (R172) SLK 300 (245 Hp) 9G-TRONIC lies a potent and efficient M 274.920 turbocharged inline-four engine. This 2.0-liter (121.5 cubic inch) gasoline unit marked a strategic shift towards forced induction for enhanced power delivery and improved fuel economy, aligning with contemporary automotive trends. The engine is longitudinally mounted at the front, driving the rear wheels, a classic sports car configuration that ensures balanced weight distribution and engaging handling characteristics.

With a robust output of 245 horsepower (Hp) at 5500 rpm, the SLK 300 delivered a significant punch for its size. More impressively, it generated a substantial 272.9 lb.-ft. of torque across a broad rev range, from 1300 to 4000 rpm, thanks to its turbocharger and intercooler setup. This wide torque band translated into immediate responsiveness and strong acceleration from low speeds, making the car feel agile and eager to rev. The direct injection fuel system and DOHC valvetrain further optimized combustion efficiency and power output.

Mated to this engine was Mercedes-Benz’s advanced 9G-TRONIC automatic transmission. This nine-speed gearbox was a major upgrade, offering more gear ratios than its predecessors, which significantly contributed to both performance and fuel efficiency. The numerous ratios allowed the engine to operate within its optimal power band more frequently, resulting in smoother acceleration and improved highway cruising economy. The SLK 300 could sprint from 0 to 60 mph in a brisk 5.5 seconds and had an electronically limited top speed of 155.34 mph, cementing its credentials as a genuine sports roadster. Despite its performance capabilities, the car also featured a Start & Stop System, contributing to its Euro 6 emission standard compliance and respectable combined fuel economy of 40.6 to 37.9 US mpg.

Design and Features

The design of the Mercedes-Benz SLK (R172) SLK 300 carried forward the elegant yet athletic aesthetic that defined the third-generation SLK. As a two-door, two-seat roadster, its primary allure was the open-air driving experience, seamlessly facilitated by its signature vario-roof – a retractable hardtop that transformed the coupe into a convertible at the touch of a button. This innovative feature provided the security and refinement of a fixed-roof coupe with the exhilaration of a convertible, offering the best of both worlds.

Measuring 162.76 inches in length, 71.26 inches in width (78.98 inches including mirrors), and 51.22 inches in height, the SLK 300 maintained compact proportions that made it nimble in urban environments while still projecting a substantial road presence. Its aggressive front fascia, featuring a prominent grille and swept-back headlights, echoed the styling of the SLS AMG, giving it a more dynamic and premium look compared to earlier SLK generations. The car’s wheelbase of 95.67 inches contributed to its stable handling characteristics.

Inside, the SLK 300 offered a cabin crafted with Mercedes-Benz’s renowned attention to detail and high-quality materials. Standard features included leather upholstery, dual-zone automatic climate control, and a sophisticated infotainment system. Optional amenities further enhanced the luxury experience, such as the innovative AIRSCARF neck-level heating system, which allowed for comfortable top-down driving even in cooler weather, and MAGIC SKY CONTROL, an optional panoramic vario-roof that could switch from light to dark at the touch of a button. Safety features were comprehensive for its era, including ABS (Anti-lock Braking System), multiple airbags, and a robust chassis structure, ensuring occupant protection. The car rode on a sophisticated independent suspension setup, with McPherson struts at the front and a multi-link system at the rear, complemented by ventilated disc brakes upfront and solid discs at the rear, providing confident stopping power.

Technical Specifications

Legacy and Market Impact

The Mercedes-Benz SLK (R172) SLK 300 (245 Hp) 9G-TRONIC, despite its relatively short production window from April 2015 to January 2016, left a notable mark in the compact luxury roadster segment. It represented a significant modernization effort for the SLK line, particularly with its advanced powertrain. The introduction of the potent 2.0-liter turbocharged engine, replacing the earlier 1.8-liter unit in the SLK 250, provided a welcome boost in performance and refinement, appealing to drivers who sought a more engaging driving experience without stepping up to the V6-powered SLK 350.

Its primary competitors in the U.S. market included the BMW Z4, particularly the sDrive28i and sDrive35i models, and the Audi TT Roadster. While the BMW Z4 offered a similar retractable hardtop concept and dynamic handling, and the Audi TT Roadster emphasized a more design-focused, front-wheel-drive (or all-wheel-drive) approach, the SLK 300 stood out with its distinctive Mercedes-Benz blend of luxury, sophisticated styling, and robust engineering. The 9G-TRONIC transmission, in particular, gave the SLK 300 an edge in terms of efficiency and smooth power delivery, showcasing Mercedes-Benz’s technological prowess.

The R172 generation, and specifically the SLK 300, maintained the SLK’s reputation as an accessible entry point into Mercedes-Benz’s sports car lineup. It offered a compelling package of open-top enjoyment, daily usability, and premium features, making it a popular choice for those desiring a stylish and well-appointed two-seater. Its brief tenure as the SLK 300 before the 2016 facelift saw the model renamed the SLC 300, a move intended to align its nomenclature with the C-Class sedan, from which it shared many components and design philosophies. This rebadging marked the end of the SLK nameplate, making the R172 SLK 300 one of the final expressions of the original SLK lineage. Today, these models are appreciated on the used market for their timeless design, robust build quality, and enjoyable driving dynamics, continuing to offer a taste of luxury roadster motoring.