Keith Adams tells the story of the Citroën SM – the short-lived French flagship, built between 1970-1975, and which still leaves a lasting impression today.
Was it too clever for its own good?
Citroën SM: Such glorious possibilities
When Citroën first set about creating a new French national flagship, it was with the very clear view of reliving the glorious pre-war grandes routières built by Bugatti, Delage and Talbot-Lago. Beyond that, the bosses at the most innovative of French companies was also well aware that there was a vacuum at the top of the market left by the departure of Facel Vega.
Taking the Deesse concept of 1955 and uprating it into its greatest form – the Citroën SM – ready for the 1970s, was the company’s typically bold response.
From the wish to produce a more powerful DS sprang the SM. Ordinarily, taking an ageing middle-class saloon and trying to create something special from it would result in disappointment.
Starting out with the DS
But when that car was as daring and adventurous as the DS, there’s a certain logic to such a decision. Thanks to its low-slung proportions and daringly swooping aerodynamic body, it looked like nothing else on earth. And that’s how Project S, what would ultimately become the SM, started out.
Early prototypes were built upon shortened cut ‘n’ shut DS models (above), which ultimately proved themselves in motor sport. The key to Projet S‘s genius was its technical make-up – Hydropneumatic interconnected suspension and powered disc brakes gave the DS a genuinely exotic feel. Citroën knew it could replicate that in a more upmarket version.
The only fly in the ointment was that, in the 1960s, it didn’t have an engine up to the task in its model range. The DS’s power unit was a very capable overhead value unit, with its roots in the pre-war but, if Citroën was going Jensen hunting with its new car, it would need a much stronger engine. Initial studies centred on a new six-cylinder engine, developed in-house.
The Maserati connection
The question of how to create a suitable engine more quickly was answered in January 1968. These were expansionist times for the major car manufacturers, most of which were going through a ‘grow or die’ period. Corporate mergers were all the rage. In the UK, that led to the creation of British Leyland, whereas, in France, it led Citroën to even less logical conclusions.
To outsiders, Citroën’s riposte to the mood of the moment was baffling to say the least. Pierre Bercot (below), the company’s Michelin-appointed Managing Director pushed ahead with his own expansionist policies. The company purchased a controlling interest in Maserati, industry watchers wondered why.
That’s probably because Citroën was stretching itself elsewhere at the same time: the company purchased Berliet and Panhard and also formed joint ventures with NSU (forming Comotor to work on Wankel engines) and Fiat (to form the short-lived Pardevi company).
However, for Citroën, Maserati’s integration into the family made perfect sense: it focused Projet S, as the Italian marque would build its engine, stalling plans for a triple-rotor Wankel in the process, and putting the in-house flat-six under intense scrutiny. More’s the pity…
Super engine for a new super-car
Within days of the takeover, Citroën abandoned Walter Becchia’s continuing six-cylinder powerplant programme. Instead, Bercot tasked Maserati with developing a new V6 for the SM. Maserati’s Chief Engineer, Ing. Giulio Alfieri, set about designing a fresh unit from scratch using the Indy V8’s tooling. It needed to be compact and light to work with Citroën’s traditional FWD layout, which forced the gearbox forward of the axle line, effectively turning it into a mid-engined car.
Turning the 4136cc Indy into a sub-2.7-litre V6 to fit into France’s 15CV puissance fiscale tax band required a shorter-throw crankshaft and a reduction in stroke from 85 to 75mm.
A one-millimetre smaller bore size was the last change needed to get the capacity down to a tax-friendly 2670cc, although further work was essential to allow the engine to work with Citroën’s twin-shaft five-speed manual gearbox – the same unit that would end up being used in the Lotus Esprit.
Citroën SM: Suitably exotic power
The Maserati-developed V6 was certainly advanced – and so it should have been, effectively being three-quarters of a supercar motor. It was all-aluminium, had quad camshafts and, at 140kg dry, it was exceptionally light.
Being based on the V8 left it with a 90-degree vee-angle, which was far from the ideal 60-degree that V6’s favour. Conceptually, that was how it was going to be – the Indy V8, simply shorn of two cylinders – but, as things turned out, it ended up being all new apart from the cam followers.
It was a remarkable achievement by the Italians. Alfieri had been given six months to come up with the first Indy V8-based V6 prototype, and he did the job in three weeks. His target was to produce an engine with 150bhp, yet in the end the offbeat V6 was capable of delivering 200bhp depending on camshaft profile. In production form with three Weber 42DCNF2 carburettors, it would make do with 170bhp.
As for the rest of the SM’s technical package, it was a mixture of DS carry-overs and innovations, and not further revolution. However, as the 1955 car was so far ahead of the game anyway, the SM would still emerge as a machine that was at least 20 years before its time.
Suspension was a refined version of the DS’s Hydropneumatic set-up, while the braking system remained powered by the suspension hydraulics; it now had discs all round instead of a mixture of discs and drums.
The main innovation was the steering. The SM’s powered system was known as DIrection à RAppel asserVI – DIRAVI, and was a speed-sensitive set-up which was distinguished not only by its super-high gearing of two turns from lock to lock, but also by its hydraulically assisted self-centring. The system’s party trick was that it would always pull the wheel to the centre, engine running or not – not that you’d want to do that on a regular basis.
And the faster you went, the heavier it became. Sounds artificial but, as we will see, it works a treat on the roads.
Geneva 1970: breath-taking Citroën unveiled
As for the styling, Citroën really wanted to make a massive splash. Although at the time of the car’s launch no single designer was credited, it’s now known that the SM was mostly the work of styling chief Robert Opron.
As a piece of design, it remains a true love-it-or-loathe-it effort – the long nose, curved rear window and drooping tapered flanks take some getting used to. It also has good and bad angles. Yet there was no denying its aerodynamics – in the wind tunnel the original model boasted a drag coefficient of 0.25, while the production car was nearer 0.34 (still better than the much-lauded 1983 Ford Sierra).
But thanks to a glazed and grille-less front-end dominated by six Cibié halogen headlights – with the inner two set up to swivel with the steering, allowing you to see round corners – it had huge autoroute presence, with little chance of being mistaken for any other car.
A massive splash from Paris
The latter stage of Projet S development programme was completed in remarkably little time. Barely more than two years after the French company’s purchase of Maserati, it debuted the SM at the Geneva Auto Salon.
The press and public were blinded by science, especially as the car was displayed alongside the equally futuristic GS – the gap-filling family model (which also rode on Hydropneumatic suspension and sported a Kamm-tailed wind-cheating body) that showed the world Citroën really was at the cutting edge. And in the spring of 1970, the SM was as cool as Brigitte Bardot in a little black Chanel dress.
Of course, in the starry-eyed optimism of the opening weeks of the new decade, the SM really did appear to have it all.
Citroën SM on the road and track
The first road tests appeared in 1970 – both Autocar and its weekly rival Motor decided not to wait for the UK cars to arrive. In both cases, performance figures failed to match up to Citroën’s claims for the SM.
When the magazines strapped their testing gear to the SM, its allure weaved a spell that had them reaching for new superlatives, despite disappointing performance figures. Enthralled by unheard-of levels of straight-line stability, combined with ultra-responsive steering and brakes, Autocar magazine spoke in terms of being able to fling the SM around ‘like a Lotus Elan’ in tight corners.
However, the Citroën gave out mixed messages which the road testers took time to understand fully. DIRAVI was a new experience, and seduced them into thinking the model handled like a sports car – yet, in reality, the SM still understeered and rolled like a DS – perfect for France’s heavily-cambered back roads.
It’s just that with two turns from lock to lock and artificial feel through the small, fat, single-spoke wheel, the steering was telling fibs. However, to rough-house the SM was to entirely miss the point.
Good and bad in competition
Citroën SM guru, the late Andrew Brodie, proved the car’s ability on road and track. ‘Team Brodie won the 2007 Tour Auto Regularity using my SM, with Bob Linwood driving and his wife navigating.
We came second equal in Tour de España, and last year won Tour Britannia, so the car can’t be as bad as some people reckon,’ he said. ‘It is the finest GT ever made. No vehicle has the dynamics of the SM, and you won’t find another that steers as well. The faster you go, the more confident you get.’
And that’s the point. It was – and remains – a GT car par excellence. ‘The difference is the straight-line composure,’ Brodie continued. ‘You don’t come off on bends, either, and it doesn’t wallow.’
Autocar magazine ran one in the 1974 BRSCC Avon Tour of Britain (above), and didn’t do quite so well, finishing near the tail of the field. The magazine’s Editor, Ray Hutton, rode alongside Grand Prix driver Howden Ganley, where they learned a lot about Hydropneumatic Citroëns.
After the event, Ganley concluded: ‘Now we know why people don’t race Citroëns!’
Driving an SM – a star of the 1970s
In 1974, at the end of his 10,000-mile long-term test, Autocar Editor Ray Hutton said: ‘Altogether the SM is an odd amalgam of characteristics. Its startling, super-streamlined body could not be anything but a Citroën and its aerodynamic efficiency, shown by its maximum speed and lack of wind noise, are what one would expect from the ﬂagship of this very imaginative ﬁrm.
‘The Maserati V6 engine emits a splendid racing growl under hard acceleration and has quite a harsh feel to it when working hard. Similarly, the manual five-speed gearbox has a precise ‘gated” change that would not be out of place in an Italian sports car’ – Autocar magazine
‘Somehow, with such a futuristic appearance a conventional power unit and transmission seems out of place; it deserves a gas turbine and fully automatic transmission at the very least.’
Despite reliability issues, he loved the car, and concluded: ‘As enthusiasts we have tended to dwell on its technical marvels but let us not forget that as an attention-getter the SM is supreme.’
In its December 1971 issue, CAR compared the SM with the BMW 3.0CS and called an easy victory for the French car. It wasn’t perfect, though: ‘The main snag with the Citroën is the fact that it will not be available with right-hand drive for some considerable time, so those who are brave enough to buy it in LHD form will have to suffer.
‘However, the SM offers an almost incomparable ride, top-class steering, braking and handling, a punchy if noisy engine, and futuristic appearance inside and out. On that basis can there be any choice but the Citroën SM?’
Driving an SM today – still a modern experience
Driving a standard example today takes much less getting used to than it must have done in the early 1970s, yet you still need a mental reboot to get the best out of an SM. It’s a wide car, and outward visibility isn’t its strongest point, but it’s the steering that will dominate your impressions. The set-up is delightful and cerebral – on the road, you’ll rarely need more than a quarter of a turn, but the hypersensitivity discourages a lazy driving style.
Instead, you’ll be inclined to hold the wheel at the ten-to-two, and never will you want to drive one-handed (because the weight of resting a single hand on the wheel will have an SM turning), or allow the wheel to slide through your fingers exiting a bend, such is the strength of the self-centring. As for attacking bends, you feed the car in, allowing it time to settle into its roll angle; pitch an SM in, and it’ll lurch in an unseemly way.
‘That slightly offbeat-sounding V6 was more than man enough for the routes nationales and autoroutes you would enjoy on the way down to the south of France.’
Compared with the GT price opposition of its day, such as the Jaguar E-type Series 3 and Jensen Interceptor, the SM was considerably down on power. A standard 0-60mph time of around nine seconds was middling at best, although the 137mph maximum speed was exceptional for a 170bhp car of this size.
But that slightly offbeat-sounding V6 was more than man enough for the routes nationales and autoroutes you would enjoy on the way down to the Côte d’Azur. And although overtaking in an SM was harder work than in its muscular British rivals, holding high speeds and maintaining your averages was easier thanks to its overall levels of chassis refinement.
And nothing else on earth looks like an SM. As Ray Hutton said in 1974: ‘Even in France it turns heads and, in the little villages of La Mancha in Central Spain, the inhabitants treated it with the suspicion and wonder of something from Outer Space. It is a strange mixture, the SM. Mechanically ornate; simple in line; beautiful yet functional. A girl friend of mine described it as ‘the sexiest car in the world”. I know what she means.’
Fleeting success followed by disaster
Yet, the SM enjoyed only a fleeting honeymoon in the marketplace. This was probably because its appeal was more limited than Citroën had ever anticipated. In 1971, the model’s first full year of production, 4988 rolled off the line – but, in 1973, when the effects of the world economic crisis were beginning to affect all large car sales, that total dropped to 2619.
And the following year, when Peugeot wrested control of Citroën from its long-time partner Michelin in a Government-brokered deal, production fell off a cliff to a mere 294. It looked like the game was up by that time.
However, by then, Citroën was fighting for its very survival thanks to its loss-making habit, an inability to amortise the SM and GS’s development costs and tooling up for CX production.
Reliability issues soon spread
Even while the car was in production, it was earning a reputation for unreliability – and not from the complex suspension system which lay-people continue to fear to this day, but due to the Maserati engine.
The weakness of the rear timing chains that drove the V6’s overhead camshafts was well documented, and word soon spread that the SM was a fragile beast. The oil pump and ignition system were also failure-prone, as was the air-conditioning.
Citroën’s response was to sweep the problems under the carpet, and it wasn’t until much later, when the specialists got their hands on the SM, that these issues were resolved. Had it survived the 1975 Peugeot takeover, the model might have recovered with factory fixes, but that’s a matter for conjecture now.
Yet the reputation for fragility stuck and, even today – nearly 50 years on from its launch – enthusiasts will shy away from an SM, afraid of its engine and worried the suspension system won’t work. That’s probably why the French masterpiece remains such an underrated commodity, but the truth is that the SM is a dependable car for an understanding owner – and one that’s just so magnificently cool.
Limited development of the promising concept
Despite huge investment in the project, Citroën developed the SM sparingly. Electronic fuel injection arrived in 1972, upping the top speed to 142mph, and a 3.0-litre auto version was added the following year – but that was it.
The SM’s high-pressure hydraulics found their way to the Maserati range – with DIRAVI making the Khamsin uniquely responsive at the helm in the supercar set – and its engine was installed in the Bora to create the Merak. Yet remarkably little of the SM’s technology, beyond its wonderful DIRAVI steering system, filtered into the rest of the Citroën range.
There were SM-based specials produced by third-party coachbuilders, though. Long-time Citroen partner Chapron, built the Mylord convertible and Opera saloon, as well as a pair of presidential limousines for the palace. Heuliez made the SM Espace – a clever open-topped version with a Triumph Stag-like T-bar roof and sliding roof panels.
Ligier built the SM-engined JS2, while Maserati used its V6 in the Merak and short-lived Quattroporte II. But as nice as these were, they were simply a glamorous side-show to this tale of woe.
Peugeot’s accountants call time on the SM
As nice as it was having a national flagship, the SM was nothing more than a high-profile loss-maker in the eyes of Peugeot’s accountants. Citroën had seen the dead hand of its new master being readied to kill the SM, and tried to head it off by setting up a deal with Ligier to quietly build the model at its factory in Abrest.
However, the arrangement took time to establish, and Ligier produced a mere 135 examples before Peugeot finally axed the SM – after off-loading Maserati in May 1975. Once that decision was made, the bosses didn’t even allow Ligier to assemble the final few unfinished cars, ordering them to be sent to the crusher instead. And that was it: the SM was dead after a mere 12,920 had been built during a five-year production run.
It would be easy to blame the First Oil Crisis and a stumbling world economy for the death of the SM but, in reality, it was a car that few really understood. And even fewer actually lived the romantic Nice-by-lunchtime lifestyle for which the model was so clearly conceived (and which was so beautifully captured in Citroën’s brochures and press photos).
- Concepts and prototypes : Hyundai/Rover Oden (1992) - 9 November 2023
- Opinion : So, maybe the Montego was the best they could do… - 8 November 2023
- The cars : Austin Montego (LM11) development story - 7 November 2023