• 1937 Mercedes-Benz 540 K Special Roadster

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The 540K was the ultimate prewar Mercedes-Benz. And if we’re going to further subdivide the model by different body styles, the Special Roadster was the ultimate 540K. Build by special order only, the Special Roadster was one of the most expensive and exclusive cars of its day, and could be considered the pinnacle of prewar German


The 540K is also distinct in being one of the few prewar European luxury cars to come from a company big enough to have a presence outside of Europe. Because while it wasn’t unheard of for an American to own a European car in the years prior to WWII, the logistical framework often didn’t exist for them to buy these kinds of higher-end machines that needed to be special ordered.

The 540K is actually an evolution of the 500K, with this being based on the still earlier S/SSK. But the cars are not as similar as this might make them sound, and while the 540K used a lot of the same architecture as the 500K, the chassis construction was changed completely from that of the 500K, thanks to engineer Gustav Rohr, on loan from the highly successful Mercedes motorsports program.

Updated 02/01/2016: The Mercedes-Benz 540 K Special Roadster shown here just went under the hammer at RM Sotheby’s . Did it go for the expected $10 million? Check out the prices section to see for yourself.

Continue reading to learn more about the Mercedes-Benz 540 K Special Roadster.


1937 Mercedes-Benz 540 K Special Roadster High Resolution Exterior
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1937 Mercedes-Benz 540 K Special Roadster High Resolution Exterior
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1937 Mercedes-Benz 540 K Special Roadster High Resolution Exterior
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So the Special Roadster isn't quite as big as the sedan versions of the car that were built, but it is by no means a small car.

The bodywork of the Special Roadster is something of a design marvel. Thanks to the work of designer Hermann Ahrens, the car looks to be fairly small, even though it is actually a full 17 feet long. The 540K came in a number of different body configurations, with Mercedes making both short and long wheelbase versions of the chassis. So the Special Roadster isn’t quite as big as the sedan versions of the car that were built, but it is by no means a small car. But it was very light when compared to its competitors.

The chassis layout was the same on the 540K as it had been on the 500K, but Mercedes updated the design and replaced the heavy girder-style construction with a tube frame, the same style as was being used on the company’s all-conquering Silver Arrow racecars at the time. All 540K models are attractive, but the Special Roadster is exceptional. Its curvacious bodywork is a rare example of Art Deco styling on a German car.


1937 Mercedes-Benz 540 K Special Roadster High Resolution Interior
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Considering the sheer size of the car’s external dimensions, the interior of the Special Roadster is pretty small. This isn’t especially unusual for this segment during this time period though, and there were plenty of two-seat coupes and convertibles during this period that were even bigger. And like those cars from companies like Bugatti or Duesenberg, the interior of the 540K had an elegant interior made of fine materials.

Because even though Mercedes-Benz was a much bigger company than the boutique manufacturers that made custom couchbuilt for the wealthiest people of the day, the company managed to avoid a mass-produced feel in the car. The 540K had its own factory, complete with a huge staff to help meet the wishes of the wealthy 540K buyers.


1937 Mercedes-Benz 540 K Special Roadster High Resolution Interior
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As with other parts of the car, the engine was closely related to one found in Mercedes race cars, and was originally developed by Dr. Ferdinand Porsche. The 5.4-liter inline-8 engine is where the “540” in the car’s name comes from, while the “K” stands for “kompressor,” meaning the engine was supercharged. The supercharger system is one we’d think of as odd today, a Roots-type blower that wasn’t normally running, but could be engaged either manually for short periods or automatically at wide open throttle.

The engine therefore has two different power ratings, 115 horsepower for normal conditions and 180 horsepower when the supercharger in engaged. Combined with the relatively low weight of the car, the power was enough to make the 540K a quick machine, especially the smaller versions like the Special Roadster.


1937 Mercedes-Benz 540 K Special Roadster High Resolution Exterior
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For as expensive as it was the 540K sold in pretty respectable numbers. But the Special Roadster was a different story, as one of the more expensive versions of the car, and one that was available only by special order. Just 26 units of the car were ever built, and there are some variations from one to the next. For example, the one you see here has the high doors, which were in line with the top of the hood. Other versions had doors that dipped down, or a shorter tail, and obviously a few were in right-hand drive.

These cars sold for in excess of $10,000 when new, and this one apparently went for $14,000. That was a tremendous amount of money in 1937, and that made the Special Roadster one of the most expensive cars in the world. Today, it is still one of the most valuable cars in the world, although that too varies a bit. This particular car is an especially well preserved example, with just over 10,000 original miles on it. It went under the hammer on January 29th, 2016 at RM Sotheby’s auctions and sold for $9.9 million.


Bugatti Type 57 Atalante

1938 Bugatti Type 57C Atalante High Resolution Exterior
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Like the 540K, the Type 57 was build in reasonably big numbers for what it was. But if you want one with a body type about as rare as the 540K, the Atalante is the one you want. It is also one of the Type 57 body types that often had a supercharger installed, although unlike the 540K, the Bugatti’s blower was always on. That made it generally faster than the Mercedes, although today the 540K is worth a bit more.

Read our full review here.

Duesenberg Model J

Since the 540K we’re talking about here was first sold in the U.S., it really faced more competition from American luxury brands than European ones, and in this price range, that meant the Duesenberg Model J. The Model J was the most expensive, and most exclusive American luxury car at the time. This is especially true of supercharged versions, which could put out double the horsepower of a 540K with the supercharger engaged. It could sometimes cost twice as much as well, and one sold a few years ago for more than $10 million.


1937 Mercedes-Benz 540 K Special Roadster High Resolution Exterior
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There were plans at one point to enlarge the engine of the 540K and evolve the model into a new car called the 580K. But then WWII came along and nothing beyond the first 580K prototype ended up being built. So the line ended at the 540K, with the cars being built after the war taking on an entirely different form. So the 540K was the last and most advanced form of prewar Mercedes luxury, and it has to be said that it is absolutely beautiful. It will be very interesting to see if this one beats the previous 540K Special Roadster record sale price of $11.7 million, set in 2012.

  • Leave it
    • Basically any other 540K would be a lot cheaper to get a hold of
    • Strange supercharger setup, and not very powerful without it
    • Enormous

Source: RM Sothebys

Jacob Joseph
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