Citroen SM History, Reviews, Features & Specifications

Andre Citroen was a French national of Dutch parentage - an engineer who had been a gear maker to the car industry before the outbreak of World War I and a manufacturer of munitions during it. After the war ended he converted his factory to the manufacture of motorcars, adopting as his emblem the double chevron which was representative of the double helical tooth formation of the gearwheels which had made him a wealthy man.

After a moderately good car, the 10hp, his first big success came with the 5CV - a car of some 7hp, thanks to the difference between metric and imperial horsepower - which was initially a two-seater. With the addition of a centrally-positioned rumble seat it became widely accepted as the ‘Cloverleaf’. It was to the French motor industry what the Model T was to the American, the Austin Seven to the British and the Laubfrosch (tree-frog) to the German. In fact the Opel Laubfrosch was a bolt-for-bolt copy of the Citroen and the subject of a successful lawsuit. Adam Opel paid gladly; in fact he had budgeted for it.

Citroen’s own prestige as an engineer was high; the company introduced the all-steel body to Europe in 1925, were the first with Ford-derived mass production, and then made the first monocoque car in 1934. Unfortunately the tooling and production costs of the elegantly innovative front-wheel-drive car were too much, and the company had to be rescued by Michelin. Andre Citroen died shortly afterwards, and never saw his Traction Avant in production.

It was the car the Citroen company had been waiting for, and saw them permanently established as a major force in the European car industry. It continued to be built for the next 23 years, and almost 760,000 of them were made. Few of the prewar roadsters survive today: in fact most of the existing Tractions are the later 1911 cc 60hp models with which the model ended its life in 1957.

It was replaced by the revolutionary DS 19, which was the first Citroen with truly revolutionary aerodynamics, giving it a futuristic appearance. It was on this model that first use was made of hydropneumatics; the DS 19 had a self-leveling suspension system which ‘collapsed’ when the engine wasn’t running, and pumped itself up after the car was started. It was also the jacking system for tire-changing, and gave power to the brakes -inboard front disks were standard.

The original engine was a hemi-head update of the long-stroke inline four which had been at the heart of the Traction, although it was later replaced by a more modern powerplant. Other refinements which came later were the swiveling headlamps, which were also part of the hydro-pneumatic system and turned with the steering wheel, automatic transmission and a five-speed manual stick shift. Total sales of the DS series -19, 21 and Pallas - ran to 1.5 million until it was finally dropped in 1975.

Although Citroen had never made a real sports car other than the Traction roadster, they did have ambitious plans for a genuine GT car, and their acquisition of the ailing Maserati setup in 1968 was, from this point of view, extremely fortuitous. Plans for a co-production between Citroen and Fiat had collapsed after Fiat had made it clear that they wished to have control over the products ; Citroen would not accept, and the collaboration never really got off the ground.

Work went ahead on the Maserati-baied Grand Tourer, which would eventually emerge in 1970 at the CitroenSM. It was destined to put all the technical features of the DS series into a more modern and sophisticated design, with yet more technical advancement. Maserati were called upon to design the engine for it, and the result was a compact and swift, if over complex V6 installation based on an existing unit.

The cleverest part was its compactness. A mere 12.25 inches long, it was all aluminium, with the induction system for the three dual-barrel Weber down-drafts built into the cylinder heads. Quad overhead cams were chain-driven by a convoluted system hidden deep inside the engine. In order to accommodate the front-drive setup the engine was fitted to the car backwards, with the transmission sticking out towards the front, which made any work on normally vulnerable items like timing chains not only time-consuming but also extremely expensive.

To compensate, the engine produced 180hp from its 2670cc, and a healthy 171 ft/pounds of torque at 4000rpm; enough to get its 30001b kerb weight up to almost 140 mph - not bad for a full four-seat tourer which dealt in ultimate luxury at every level. To be fair, most of its 116-inch wheelbase was full up with engine, since Maserati had chosen to ignore the gearbox-under-engine solution which was then gaining currency on front-drive cars and is now all but universal, so the passenger compartment was by no means king size.

Even so, the Citroen SM boasted all the advantages of the DS series and a few more besides. The engine/ transmission layout had enabled the SM to inherit inboard front disks, outboard rear disks and the Citroen self-leveling suspension. New power steering - with servo assistance in directly inverse proportion to engine revs - made parking finger light but allowed the driver maximum ‘feel’ at cruising speed. Power centering was also a feature; left untouched, the wheels would return from either lock to straight ahead if the engine was running. In any case the 9.4:1 steering ratio was unusually quick, and one full turn of the wheel would take the wheels from straight ahead to the full lock position in either direction.

Across the front were six lights in two pairs of three, totally enclosed behind a flush glass panel which also included the license plate and gave the SM smooth aerodynamics. There were two long-range driving lamps, two dipped driving lamps and two swiveling lamps which were, like those on the DS, hydraulically powered and swiveled with the steering wheel, advancing a few degrees ahead of the front wheels. Each bank of three lamps was fitted on a pivot through its horizontal plane, and was thus self-leveling. Application of hydraulics here too prevented the lamps swinging wildly, but regardless of load and other factors like heavy braking, the SM’s headlamps remained horizontally aligned.

Tinted glass and airconditioning were options and fuel injection was added in 1974, but the oil crisis had arrived and cars like the SM were going out of fashion. Citroen’s own finances were pretty shaky as well, and when their Berliet truck operation had been handed on to Renault and Peugeot had reluctantly stepped in to help with car production, the Maserati connection had been acquired by De Tomaso and the SM was gone; some 13,000 of them were made in total, and they remain the subject of owners’ clubs and collectors’ auctions today.