50 Years of the R107

Graham Robson
Now is the time to celebrate an important fiftieth anniversary – the introduction of the original R107 SL two-seater to the North American market. Not only that, it is surely the right time to remember that this model range – with all its derivatives and its multitude of engine choices – was on sale for 18 years, and that 300,175 of this family would eventually be built – almost all of them in Stuttgart.
Now is the time to celebrate an important fiftieth anniversary – the introduction of the original R107 SL two-seater to the North American market. Not only that, it is surely the right time to remember that this model range – with all its derivatives and its multitude of engine choices – was on sale for 18 years, and that 300,175 of this family would eventually be built – almost all of them in Stuttgart. 

But, hang on. Each and every model got a new designation to denote the engine which was fitted, so it would be easy to see this affectionate tribute being submerged in acronyms. To avoid that, I’m going to give it a nickname. All cars, even those as patrician as Mercedes-Benz models, gain nicknames – the original 300SL was always lovingly known as a "Gullwing," its successor was the "Pagoda," so in this case I’m going to christen the R107 as "Rodeo Drive."

I’m sure that this is appropriate, and even friendly, for the R107 must have been the ideal car to use, peacefully, silently, and with the soft-top furled, by well-to-do owners who were on their way to lunch at an up-market hotel, or going shopping in one of the most exclusive neighborhoods in North America.
How can I best celebrate a range of sporty cars which filled so many market sectors, made so many customers happy, and which led the three-pointed star’s line as the only open roadster which Mercedes-Benz would make throughout the 1970s and 1980s? Definitely not by quoting detailed production figures at you, or by grinding out line after line of engine power outputs, transmission details, and minor year-over-year changes. After all, we have a Buyer's Guide for that – see page 68.  Instead, this tribute will focus on the character and the way the company succeeded in meeting so many different challenges with the same basic car, for almost two decades.
A celebration of style
It's easy to start by celebrating the R107’s style because the last cars that cruised happily down Rodeo Drive in Los Angeles, or the Boulevard des Anglais in Nice, France, or up and down Park Lane in London, looked almost the same as those which were first shown to the world in 1971. U.S.-market cars always had four round headlamps, the rest of the world settling for oblong units. U.S. market vehicles gained larger and more obtrusive front and rear bumpers (needed to make sure that the cars could pass all the latest crash test requirements), but apart from changes (and differences) to the fascia and instrument displays from time to time, that was about it. 
For those who can tell the difference between a 1970s model and a 1980s car, congratulations. That means that you can pick up on the details that Mercedes' stylists and engineers thought necessary over the years; a wheel change here, a spoiler alteration there, a bumper change to meet regulations here, and a fascia re-alignment there. However, as time passed no significant change was ever made to the basic layout of what was a phenomenally successful machine. 
True to its original design
Longevity of design was true on the surface, but not under the skin. Over the years there was an increase in the weight of the machines. This was not only due to the bulk of the engines, which varied greatly over the years, but also due to the mass of extra reinforcement to the body structure needed to keep abreast of advancing safety regulations. Yet if you compare the R107 to other sports cars of the era (we're looking at you, Nissan) the weight gain is almost trivial. 
Consider these factory-supplied figures: the six-cylinder 280SL of 1974 weighed 3,307 pounds, whereas the very last of all the R107s, the American-market 560SL, weighed a sturdy 3,704 pounds. The engineering team worked wonders to keep that weight gain to a minimum, but there are limits.
All that brings me neatly to the question of body shells or, to be specific, the two different types of the 107. There were the open-top SL two-seaters, and the longer-wheelbase, close-coupled four-seat hardtop coupe, the C107 SLC. 
It’s no secret that design work on the original roadster had begun in late 1967, but that a scheme to add the SLC did not follow for some months to come. The reason, I feel sure, is that the company’s far-seeing marketing department had noticed how well the coupe versions of conventional Mercedes-Benz saloons had recently been selling, and they concluded that to add a more specifically up-market, higher-performance four-seater might just be a bonus, and it was, as the total sales of SLC models amounted to more than 60,000 in ten years. 
For a moment, therefore, let’s talk engineering. Two wheelbase lengths were involved – 96.9 inches for the two-seater SL and 111 inches for the four-seater SLC. Both were based on the same steel platform, and the planners were certain that the new cars were going to have long production runs, so they could spend money to make this a new and unique design. Although it was clear that the front and rear independent suspensions, the steering systems, and the brakes had all been lifted, and barely modified, from the "New Generation" sedans that had made their debut only three years earlier, the underlying platform was not directly related. In fact, the new generation W114/W115 sedan sat on a wheelbase that was eleven inches longer than the original R107, and it was just under three inches shorter than the wheelbase eventually chosen for the C107 SLC. 
Even so, it was brave of the company to split the offering into two distinct sub-types – a compact two-seater, with a top that opened, with a removable hardtop, accompanied by a significantly larger four-seater with a fixed roof. No other rival made such a bold step at the time. It's worth noting that the difference between the two types was fourteen inches in length, and yet only 110 pounds in unladen weight. 
A progression of engines
Observers often marvel at the way Mercedes-Benz made so many changes to the engines powering the R107 SL line. Some were unplanned additions to the product line as Mercedes-Benz reacted to outside forces such as two separate energy crises in 1973 and in 1979, and the serious cost inflation which followed each of those events. Over the long production life of the R107 SL range, Mercedes-Benz had to face the steeply rising cost of gasoline, new exhaust emissions regulations, new crash test rules, and plain, long-established market forces.
When the R107 line was launched, the automotive world seemed to be stable. Fuel costs were low, and the prosperous countries where the SL and SLC would be marketed were optimistic about the future. 
The company’s original planning centered around the new 3.5-liter M116 V8 engine (see The Star, November-December 2020) for most world markets, and the 4.5-litre version of the same engine for American-market cars. At that time, there was no thought at all of producing a "poverty spec" version with a smaller or more economical engine. In fact, it was not until the first energy crisis struck that an M110 six-cylinder engine was squeezed into the R107 line. 
A car to love for a lifetime
All this, of course, was achieved in the most robust and well-developed sporting Mercedes-Benz that had ever been put on sale. When I settled into the comfort of the European-market 350SL for the first time, I was surprised by the way this sturdy new vehicle felt and the reassuring way it handled. Here was a 125-mph machine that seemed to be no trouble at all. This sporty new Mercedes-Benz SL was powerful, predictable, effortless, and safe. The R107 SL was  also built like a tank.
It wasn’t until much later that I heard that engineering staff in the company’s development department had felt very much the same way. Internally, the Mercedes-Benz team had nicknamed their new prototype "der Panzerwagen," which had a military connotation that was still not quite politically correct in the 1960s. A fellow author went on to suggest that, "this word means tank or armoured car, and everything about the new models testified to the aptness of this description."  
I must end this affectionate survey with a comment about performance. Never forget that the R107 was originally marketed in the 1970s in a nation where 55 mph speed limits multiplied, where weight seemed to grow on all existing cars, and where there was much discussion about the price of gasoline and the rate at which it was all being consumed. Let’s just remind ourselves that each and every SL of this period could exceed 120 mph, and this fact caused much controversy on Capitol Hill in Washington, D.C. The most powerful of the V8-engined models could pass 140 mph, and the specially-developed 450SLC 5.0 models of the late 1970s came close to upsetting the World Rally Championship. 
It’s difficult to believe that all this extraordinary achievement started well over half a century ago.