Guide: Mercedes-Benz W121 190 SL

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Background

To complement the wild Gullwing-doored W198 300 SL, Mercedes-Benz offered a less expensive two-seat Convertible for touring and utility use.

Whereas the advanced 300 SL was arguably the ultimate road-going production car available at the time, the junior W121 190 SL opened the Sport Leicht range up to a wider audience.

Sporty and elegant, the 190 SL had more humble underpinnings than its big brother, but shared the same basic styling.

The concept for both models was proposed by Max Hoffman who had been Mercedes’ US importer since 1952. Hoffman began to lobby for the brace of SL variants in early 1953.

Mercedes unveiled the two cars at the New York Motor Show in February 1954.

Although at this stage the 300 SL was almost production-ready, the 190 SL still required much work.

The first pre-series examples were assembled in January 1955 and the production version was displayed at the Geneva Show in March.

Deliveries of customer cars started in May 1955.

Chassis

Unlike the 300 SL, which came with a tubular spaceframe chassis, the 190 SL was based upon a modified unitary steel floorpan derived from the W121 Ponton. This arrangement was deemed acceptable owing to the less extreme performance on offer. It was also much simpler and cheaper to manufacture.

Compared to the W121 Saloon, the 190 SL had a wheelbase shortened by 250mm to 2400mm. However, the same front subframe arrangement was retained which saw the engine supported only at the front.

As per the majority of the Mercedes range, suspension was fully independent with double wishbones up front and a swing axle at the rear. Telescopic coil springs were fitted all round along with a front anti-roll bar.

230mm servo-assisted drum brakes were standard equipment.

13 x 5-inch steel disc wheels were normally accessorised with a body coloured Mercedes-branded hub cap.

A 65-litre fuel tank was installed under the boot floor.

Engine / Gearbox

The 190 SL was powered by a new Type M121 B2 inline four cylinder engine that went on to be used in the rest of the 190 range. It featured a cast-iron block with a single overhead camshaft aluminium-alloy two valve head.

Displacement was 1897cc. Like the 300 SL, bore stayed at 85mm. The stroke was reduced by 4.3mm to 83.6mm.

Mercedes opted for an 8.5:1 compression ratio and fitted a brace of twin-choke Solex 44 PHH sidedraught carburettors.

Peak output was 105bhp at 5700rpm and 105lb-ft 3200rpm.

Transmission was via a four-speed manual gearbox and single-plate clutch.

Bodywork

Visually, the 190 SL’s styling was clearly derived from the handsome Gullwing.

The front end was home to another wide intake. This was embellished with a chrome shroud and large three-pointed star, either side of which were decorative whiskers.

Similarly, all four wheelarches featured distinctive splash guard eyebrows.

Full width bumpers were fitted front and rear.

While the front wing line was also largely imported from the Gullwing, the rear fenders were considerably more pronounced and gave greater definition than the flat-sided W198.

The Gullwing’s elaborate engine cooling vents located behind each front wheel were deleted and the cockpit was made wider to allow for a more spacious interior.

Whereas the 300 SL had two distinct power bulges on the hood, the 190 SL came with just one.

The folding canvas roof was easy to operate. When lowered, it stowed almost flush with the rear deck. A leather roof tonneau was coloured to match the rest of the upholstery.

Interior

Access to the cockpit was far easier than the Gullwing thanks to the absence of high chassis crossmembers. This meant 190 SL owners didn’t have to clamber across wide sills. As such, a conventional (non folding) steering wheel was fitted.

At a quick glance, the dashboards of the two SL variants were broadly similar.

Both cars housed a large rev counter and speedometer in a neat binnacle directly behind the steering wheel. Smaller gauges for oil pressure, water temperature and fuel were located either side of the steering column. A clock was normally housed on the glovebox door.

The metal dashboard was painted to match the exterior. The dash top and knee roll were upholstered in leather that matched the seats, door panels and upper portion of the rear quarters.

The lower section of the area behind the seats was carpeted along with the rest of the floor.

Well-padded seats tilted forwards for easy access to the back.

The two spoke steering wheel was ivory Bakelite to match the gear knob.

Options

Buyers could specify a canvas roof or no roof at all.

There was also an optional hard top which, along with the windscreen pillars and hub caps, could be ordered in a contrasting colour to the rest of the bodywork.

For a degree of extra practicality, Mercedes offered a transverse rear seat.

A radio, spot lights and bumper overriders were other upgrades.

Weight / Performance

The standard 190 SL had a kerb weight of 1400kg.

Top speed was 110mph and 0-62mph took 14 seconds.

Competition Version

For those customers that wanted the most potent example available, the first 190 SL brochure described a rarely seen variant for competition use.

These cars came with a tuned engine and a lowered body thanks to sports shocks and modified springs.

The steel doors were switched to aluminium and the normal windscreen was replaced with a small perspex aero screen.

The bumpers, roof and heat exchanger were deleted as were the standard seats which Mercedes swapped for leather-covered buckets.

Around 140kg of weight-savings were made.

Very few such cars were built and the model was no longer advertised after the spring of 1956.

Production Begins

190 SL production started in May 1955.

Production Changes

During the course of its eight year life, a series of modifications were phased in.

The first of these arrived in January 1956, when a modified front subframe was introduced that featured two additional supports for the engine.

In March 1956, broad chrome trims were added to the upper door rim.

Bigger taillights from the 220 and 219 were fitted from June 1956.

To accommodate wider rear number plates that were being introduced, plate illumination was changed in July 1957. The chromed lights originally mounted either side of the licence plate were deleted in favour of discrete additions on the inside face of each rear overrider. While this meant overriders became standard at the rear, they were still an optional extra at the front.

In September 1959, the compression ratio was increased from 8.5:1 to 8.8:1.

A month later, the hardtop rear window was enlarged to improve cockpit visibility.

From August 1960, the boot lid lock was changed and, at the same time, the bow-type handle was replaced by a recessed handle.