Mercedes-Benz SL of the R 129 model series: The technology platform celebrated its premiere 30 years ago

The Mercedes-Benz SL of the R 129 model series celebrated its premiere 30 years ago at the Geneva Motor Show. It is a technology platform: it brought innovations such as the automatically folding roll bar, integral seats and the Adaptive Damping System (ADS) into production. The model, as sporty as it is comfortable, continued to remain modern and attractive throughout its twelve-year production period. Today, the SLs of the R 129 model series are coveted young classics - and ALL TIME STARS, Mercedes-Benz Classic's own dealer, regularly has particularly attractive vehicles on offer.

Stuttgart. The new Mercedes-Benz SL caused a stir for two reasons 30 years ago at the Geneva Motor Show: on the one hand, the R 129 skilfully connects a unique tradition with innovative technology. At the same time, it perfectly combines the goals of sportiness and comfort. The result is an accomplished, open sports car which stands for 'the fascination of driving in unknown dimensions'. That's what it says in the Mercedes-Benz press kit for the Geneva Motor Show, which took place from 9 to 19 March 1989.

Customers and experts appreciate the new SL for its high technical level just as much as for its construction. As early as in 1990, the sports car wins the Car Design Award for production vehicles from the City of Turin and the Piedmont region. Bruno Sacco, Director of the Mercedes-Benz Design Department, accepts the prize. The design of the SL bears his trademark with clear lines and surfaces without embellishments, a slightly wedge-shaped body and bold accents. The construction also ensures good aerodynamics: when the standard hardtop is installed, the R 129 attains a superb Cd value of c_W=0.32.

Sporting tradition

The new SL seamlessly continued the tradition of the Mercedes-Benz SL production sports car. It began with the 300 SL (W 198, 1954 to 1963) and 190 SL (W 121, 1955 to 1963) models. It was followed by the SL 'Pagodas' of the W 113 model series (1963 to 1971) as well as the SL of the R 107 model series (1971 to 1985), from which the SLC luxury class coupés (C 107) were also derived at the same time. The legend of the SL was created in 1952 on the world's race tracks: the new 300 SL racing car (W 194) immediately won four out of five races in its first and only racing season and thus made way for the SL legend.

The development of the R 129 was picked up by Mercedes-Benz in the mid-1970s. There were once again considerations for a coupé derived from an open sports car, such as the 107 model series, but which were not realised. At the start of the 1980s, however, work considerably picked up speed. The model, which was measured in the wind tunnel in November 1981, already has the clear design trademark from the era of Bruno Sacco. On 17 October 1984 the roadster received approval for its shape, and on 10 December 1985 Mercedes-Benz determined that production of the R 129 model series was to begin in August 1988.

For the start of the new roadster in 1989, there were two models with three-litre, six-cylinder inline engines (300 SL with 140 kW/190 hp and 300 SL-24 with 170 kW/231 hp as well as four-valve-per-cylinder design) and also the five-litre V8 500 SL model with 240 kW/326 hp (from 1992: 235 kW/320 hp). The development of a top model with a V12 engine was approved by the company in December 1986.

Innovations for safety's sake

High demands for passive safety go without saying in the development of a new Mercedes-Benz passenger car model series. However, in open vehicles, alongside the conventional accident scenarios, due to the missing solid roof there is also an additional risk in the event of a rollover. Early in the development phase, the fathers of the R 129 model series therefore considered a targa solution in which the B-pillar is expanded to a fixed roll bar. This, however, would have disturbed the classic lines of the roadster.

Mercedes-Benz found an exceptionally innovative solution: the automatic roll bar. It celebrated its world premiere 30 years ago in the SL. Engineer Karl-Heinz Baumann played a central role in the invention. The preloaded spring-absorber unit erects the roll bar in critical driving situations in just 0.3 seconds.

A further innovation for passive safety - and for comfort - were the electrically adjustable integral seats, first realised by Mercedes-Benz in the R 129. The three-point seat belts with seat belt retractor and belt tensioner as well as the seat belt height adjuster and the associated head restraint adjustment were integrated in it. The innovative solutions also included passive safety, once again brought to a higher level in the new SL.

Comfortable travel - open and closed

The engineers also put a lot of development work into the fully automatic soft-top of the R 129 model series. It has sophisticated frame kinematics, and the control unit monitors the processes with 17 limit switches, amongst other things. The draught-stop also premiered in the new SL. Today, this solution is one of the standards for open vehicles. A further feature was the hardtop with a panoramic glass sunroof available in later years.

The modern chassis contributes towards the high comfort level. This includes the Adaptive Damping System (ADS), which celebrated its world premiere in the R 129. It adjusts the damping fully automatically to the respective driving conditions in fractions of a second and is coupled with automatic self-levelling.

Accomplished power

The sports car was met with an enthusiastic response and the customers exploited the production capacity available in the Bremen plant right from the start. In the first two-and-a-half production years or so, no fewer than 52,204 vehicles of the R 129 model series rolled off the production line by December 1991. A total of 25,709 of these sports cars were produced in 1991 alone. More than a third of them (34.7 per cent) were exported to North America; Germany was the second most important market with 30.4 per cent.

In the summer of 1992, Mercedes-Benz presented the new top model: the 600 SL with a V12 engine and an output of 290 kW (394 hp). It was the first SL ever with a twelve-cylinder engine. Its exclusive character was underlined by the interior with burl wood and leather. On the outside, only the model plate and the V12 badge on the air outlet slits indicated the top engine.

The reorganisation of the Mercedes-Benz model designations also applied to the SL from July 1993: from then on, the class designation came before the numerical sequence relating to engine size. At the same time, the two three-litre versions ─ the 300 SL (the last SL with this magical designation) and the 300 SL-24 ─ were replaced by the SL 280 (142 kW/193 hp) and the SL 320 (170 kW/231 hp). Both had four-valve, six-cylinder engines. The SL 500 V8 roadster and the SL 600 V12 top model also received new names. At this point, 85,300 vehicles of the R 129 model series had already been produced, with the SL being the world's most successful open vehicle in the luxury class at that time.

Exclusive special models and sportier top models further inspired the success of the R 129 model series in the 1990s. Therefore, from the direct cooperation of Mercedes-Benz with AMG in 1993, the new top model was created: the SL 60 AMG with an output of 280 kW (381 hp). Between 1994 and 2001, a total of 20 special series in various editions were created, which made up between 10 and 1,515 vehicles. The renowned special models included, for example, the Mille Miglia Edition and Special Edition.

Facelift for the SL

For the 1995 IAA, the brand from Stuttgart presented the redeveloped SL. On the outside, it could be recognised on the radiator grille with six louvres, consistently white lighting units at the front, bichromatic rear lamps and new side wall trims. The technical modifications included the new, electronically controlled five-speed automatic transmission in the 500 SL and 600 SL. Under the 'light from gas' headline, Mercedes-Benz presented the new xenon headlamps. The light current of the gas-discharge lamps was double that of conventional halogen bulbs.

The facelifted SL also premiered the new panoramic glass sunroof made from four panes of different thicknesses, which were bonded to the support structure made from aluminium. It was optionally available from 1996.

Technology for the new millennium

The SL is continuously further developed. For example, all models of the roadster receive the BAS Brake Assist from December 1997. In April 1998, Mercedes-Benz presented the again updated SL at the Turin Motor Show. The facelift included, amongst other things, new V6 engines in the SL 280 (150 kW/204 hp) and SL 320 (170 kW/231 hp) models as well as a new V8 engine in an SL 500 (225 kW/306 hp). Changes to the exterior included aluminium five-hole wheels, the visible exhaust tailpipe, outside mirrors in a form reminiscent of the SLK R 170 model series as well as door handles and lock cylinders in vehicle colour. On the inside, the new four-spoke steering wheel, display instruments with a chrome frame and the standard nappa leather appointments stood out.

Two AMG versions of the updated SL followed in 1999. The SL 55 AMG received the 5.5-litre V8 engine (260 kW/354 hp) already established in other models. The SL 73 AMG, on the other hand, found a new dimension of performance with its V12 engine and 386 kW (525 hp). A feature of the AMG models, alongside the sporty look, was the mixed-size tyres with aluminium wheels and tyres that were wider at the rear.

The production of the elegant roadster ended in 2001. Over a twelve-year production period, a total of 204,940 vehicles were produced. The most successful model was, with almost 80,000 units, the 500 SL/SL 500 with a four-valve engine. The variety of the roadster was underscored by the stylish customisation options afforded by the designo programme as well as the countless special models.

The charming R 129 model series quickly attained a special status on the young classic scene. Today, it is a coveted young classic with a star - be it a special model, AMG version or classic SL roadster. The range from ALL TIME STARS, the Mercedes-Benz Classic dealer, regularly includes particularly attractive SLs of the R 129 model series.