The 1970 Citroën SM arrived as a luxury grand tourer that treated comfort as an engineering problem, not just a matter of soft seats and thick carpets. Its creators wrapped radical hydraulics, novel steering and a sophisticated engine in a sleek body, then tuned everything so the car could cross continents quickly without tiring its occupants. More than fifty years later, few production cars have combined such serenity and such technical ambition in a single package.
The Franco‑Italian grand tourer idea
Citroën conceived the SM as a fast, long‑legged coupé that could sit above the DS and showcase the company’s most advanced ideas. Contemporary descriptions present it as a Franco‑Italian collaboration, with Citroën’s chassis and hydraulic expertise paired with a Maserati‑derived V6, an arrangement that later writers have described as a French‑Italian Automotive Symphony. The SM was introduced around 1970 and 1971, with several sources pointing to its impact as a revolution in how a grand tourer could ride and handle, and enthusiasts still highlight the 1971 Citroën SM as a futuristic French grand tourer in its own right.
From the start, the car targeted high‑speed travel on European motorways rather than racetrack heroics. Owners and historians have repeatedly framed the SM as a machine built to cover hundreds of kilometers at a stretch while keeping the driver fresh, a mission that required a new way of thinking about suspension, steering and aerodynamics. That focus on real‑world comfort, not just performance figures, established the balance that still fascinates modern observers.
Styling that served both comfort and speed
The shape of the SM signaled that this was no ordinary coupé. Styling was penned by in‑house chief designer Robert Opron, and contemporary accounts stress how carefully the body was honed for stability at speed. A key figure often cited for the SM’s body is a drag coefficient of 0.26, which placed it among the most aerodynamic production cars of its era and helped reduce wind noise and fuel consumption on long journeys.
That low figure came from a long, tapering roofline, covered rear wheels and a sharply cut Kamm tail, all of which helped the car slip through the air. The glassy, almost architectural front end, with its enclosed lights and smooth bumper treatment, was designed not just for drama but also to reduce turbulence. Period observers sometimes compared the SM to a piece of industrial sculpture, and later writers have echoed that idea by calling it a kind of Concorde of the Road, a reference that underlines both its futuristic look and its emphasis on efficient, high‑speed travel.
Inside, the car continued this blend of visual theater and functional comfort. Period images of the 1971 Citroën SM interior, including one widely shared as a “mystery interior,” show a dashboard that wraps around the driver, with deeply sculpted seats and a distinctive single‑spoke steering wheel. Commentators have described that cabin as an intoxicating blend of curves and technology, an environment that made long trips feel special rather than routine. The focus on ergonomics and visibility, combined with thick sound insulation, served the comfort side of the SM’s mission while still making a strong design statement.
Hydropneumatic suspension as rolling comfort technology
Underneath the dramatic body, the SM’s hydropneumatic suspension did more to define its character than any other single feature. Citroën had already made its name with self‑leveling hydraulic systems on earlier models, and later commentators still describe hydropneumatic suspension as Citroen’s unique selling point, often citing its GIC flare and unique and innovative character when asked what makes the brand distinctive. In the SM, that system reached a new level of sophistication.
Press accounts and technical summaries explain that the SM’s suspension combined hydraulic pressure and nitrogen‑filled spheres to maintain ride height and absorb bumps with an uncanny smoothness. The car could automatically level itself regardless of load, which meant four occupants and luggage did not compromise ride comfort or headlight aim. Enthusiast videos that walk through the SM’s features often start with the suspension, noting how the car can be raised or lowered at the flick of a lever and how it seems to float over rough surfaces that would unsettle conventional steel‑sprung cars.
Writers who have revisited the SM on its fiftieth anniversary have described this suspension as a case of technology becoming poetry in motion. They note how the system isolates occupants from broken pavement yet still keeps the body controlled during fast cornering, a combination that made the car feel both relaxing and secure at speed. The same sources emphasize that this was not a luxury gimmick, but a carefully tuned package that served the car’s grand touring purpose.
DIRAVI steering and the strange comfort of effortlessness
If the suspension gave the SM its ride, the DIRAVI steering gave it its personality. The acronym refers to a self‑centering power steering system that used hydraulic pressure to provide variable assistance and a strong return‑to‑center effect. Later technical summaries describe DIRAVI as one of the SM’s headline innovations, grouping it with hydropneumatic suspension and swiveling headlights as part of a broader Cult Status Technical Showcase.
The system allowed the steering to be extremely light at parking speeds, which reduced driver effort in town, then firm up as speeds increased, which helped stability on the autoroute. It also automatically straightened the front wheels when the engine was started, a feature that modern observers on enthusiast forums still highlight as one of the car’s most surprising tricks. This self‑centering behavior could feel strange at first, but once drivers adapted, it reduced fatigue by eliminating the need for constant small corrections on long journeys.
Some contemporary reviewers and modern testers have compared the sensation to a fly‑by‑wire aircraft, where the driver makes small inputs and the system quietly handles the rest. That comparison supports the idea that the SM’s comfort was as much mental as physical: by making the car feel stable and predictable at high speed, DIRAVI allowed drivers to relax their grip and settle into the rhythm of the road.
Brakes, headlights and other technical flourishes
The SM’s braking and lighting systems added further layers to this blend of comfort and innovation. Technical overviews of the model explain that it used high‑pressure hydraulics not only for the suspension and steering but also for the brakes, which offered strong stopping power with relatively little pedal travel. Enthusiast accounts from drivers of 1973 cars stress that once a driver learns to be gentle on the brake pedal, the system is easy to modulate and feels natural, even if the initial response is more immediate than in other cars of the era.
At the front, the SM employed swiveling headlights that turned with the steering to illuminate the road around bends, an idea that modern sources still highlight as one of its signature features. In some markets, these lights were enclosed behind glass, adding to the car’s smooth front profile. Later technical summaries group these swiveling headlights with hydropneumatic suspension and DIRAVI steering as core innovations that made the SM one of the most advanced production cars of its time.
The combined effect of these systems was a car that reduced the workload on the driver. The suspension smoothed out the road, the steering kept the car centered with minimal effort, the brakes provided strong, predictable stopping, and the lights helped the driver see through curves at night. Together, these features supported the SM’s mission as a high‑speed, long‑distance machine that prioritized ease and safety without sacrificing technical ambition.
The Maserati‑derived heart
Power for the SM came from an Italian V6 that reflected Citroën’s ownership stake in Maserati at the time. Later descriptions of the model often refer to it as a futuristic French grand tourer with Italian V6 power, a phrase that captures both the cross‑border engineering and the character of the engine itself. The unit was compact and relatively light, which helped keep weight off the front axle, and it provided smooth, flexible performance that matched the car’s relaxed, high‑speed character.
While specific output figures vary by market and year, contemporary reports agree that the SM could cruise comfortably at motorway speeds for hours, with the V6 turning quietly in the background. The engine’s willingness to rev, combined with the car’s slippery aerodynamics, allowed it to reach high top speeds for the period without straining. This mechanical refinement complemented the suspension and steering, reinforcing the sense that the car was built to cover distance with minimal stress on its occupants.
The Franco‑Italian nature of the powertrain also played into the SM’s image. Enthusiasts and historians often describe the car as a Franco‑Italian grand tourer that paired Citroën’s hydro expertise with Maserati’s engine know‑how, a combination that gave the car both technical sophistication and a certain exotic appeal. That blend of cultures and technologies remains one of the reasons the SM continues to attract attention among collectors.
Comfort as an integrated philosophy
What sets the SM apart from many contemporaries is how thoroughly comfort was integrated into its engineering. Rather than simply adding thicker padding or quieter exhausts, Citroën treated ride quality, steering effort, noise reduction and even driver workload as connected problems to be solved together. Technical summaries on The SM emphasize how many unusual features were combined in a single package, and how some of those ideas only became common on mainstream cars decades later.
Modern commentators who revisit the SM often frame it as a car that was so far ahead of its time that it redefined expectations for luxury and performance. One enthusiast reflection on Citroën SM models from 1970 to 1975 describes that period as a remarkable era in many ways, and refers to the car as The Grand Tourer That Redefined Luxury and Performance, a phrase that has been echoed in other tributes. Another piece on the 1971 Citroën SM uses similar language, again calling it The Grand Tourer That Redefined Luxury and Performance and referring to the car as The Citro, a sign of the affection it still inspires.
These retrospective views support what the engineering already suggests: the SM did not treat comfort as a secondary benefit of performance engineering, but as a primary goal that guided everything from suspension tuning to cabin layout. In doing so, it anticipated later trends in luxury car design, where active suspensions, adaptive steering and complex driver aids now work together to make high‑speed travel less tiring.
Driving impressions and the learning curve
Contemporary and modern driving reports agree that the SM can feel unusual at first, yet deeply rewarding once the driver adapts. Writers who have revisited the car describe an initial adjustment period with the DIRAVI steering and high‑pressure brakes, but they also report that once a driver becomes comfortable being more gentle on the controls, the SM becomes a delight to drive. One such account notes that once the driver relaxes their inputs, the car seems to shrink around them and flow down the road with surprising agility.
More from Fast Lane Only
