As promised in the "next to last Canepa's C & C" thread, here's a series of photos of a rolling '61 M-B 300SL Roadster chassis.
To see a 300SL Roadster is a rare enough event, with only 1858 produced from '57 through '63, to see one without its beautifully shaped body mounted so you can study the chassis, suspension and witness the engineering that went into these seminal cars is a revelation.
internally referred to as the W 198 Series, the 300 SL Series began with the "Gullwing" Coupe, with 1400 total produced from '54 through '57, 1371 in steel and 29 with aluminum bodies. As is well known, it was the very high sills, a consequence of the specific space frame configuration, with torsional stiffness being the first consideration of the designers, that necessitated the introduction of the famous roof-hinged doors, not only making entry & exit very awkward and uncomfortable, especially for women, but the resulting "S" shaped cross section of the doors made wind-down windows impossible to incorporate, resulting in an almost total lack of ventilation and airflow in the Coupe's interior.
In 1957 M-B introduced the W198-II 300SL Roadster. It was based directly on the Gullwing Coupe, but had much lower sills to enable the car to be designed with normal front-hinged doors with roll-down windows and numerous additional luxury touches. That made getting in & out a far more conventional exercise, with the folding top taking care of any remaining ventilation problems, solving both of the Coupe's main Achilles heels.
The Roadsters had the same 3.0 liter, in-line 6-cylinder SOHC slightly undersquare, dry-sumped motor tilted at 50 degrees for lower CG and better aerodynamics as the Coupes, making 215 HP @ 5800 rpm. The W-198 Series cars were the first mechanically fuel injected production cars in the world, the Bosch injection systems being directly based on the design used in the Mercedes-built Messerschmidt airplane engines of WW II.
Front suspension was by means of double wishbones with coil springs, tubular shocks and anti-roll bar. To improve handling over the Gullwing Coupe, rear suspension was changed from the original high-pivot swing-axle system of the Coupe to a newly designed low-pivot swing axle with the ingenious transverse compensator spring, coil springs, tubular shocks and pivoting radius arms. Both, the Coupe and the Roadster were built on a 2400mm ( 94.5 ") wheelbase. Four speed, fully synchronized gearboxes mounted to the rear of the engine were used. A recirculating ball steering box was mounted in an asymmetrically braced part of the forward frame structure. Large cast drum brakes were used at all four corners. So much of these details are revealed in these photos.
Interestingly and fascinatingly, a name so prominent in the earliest stages of Porsche's history in the US as well, was also chiefly responsible for convincing management in Untertürckheim to create these iconic sporty roadsters - Max Hoffmann, the ex-pat Austrian whose ideas went such a long way to popularize and romanticize the two respective marques in post-war America.
The photos are arranged more or less in a front-to-rear sequence. I apologize for the lack of ultimate detail in some areas , but it was tricky lighting and without an appropriately colored, featureless background, and given the reflective, glossy black paint treatment on the entire chassis I had to perform some post-processing I would not have done if the photos had come out more illustrative.
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Originally Posted by Nine17
