The New Frontier : [Part One]

We profile the incomparable SM.

La Fluidité. Image: autoevolution

Observing 50 year old events through modern eyes can make for a faulty tool, yesterday’s visions of the future tending to appear somewhat naive to twenty-first Century sensibilities – as much a consequence of socio-economic factors, evolving customer tastes, not to mention the relentless march of time itself. Few carmakers have done more to define the modern automobile than Automobiles Citroën – especially during the post-war era – not simply in design, but also in terms of systems engineering, in particular its widespread adoption of aviation-inspired, engine-driven hydraulics.

If only Citroën could have made a car as technologically and stylistically advanced, as resolutely modern as the 1970 SM, it could only have done so during this fecund (some might say profligate) period of their history. Today, the SM still appears thrillingly futuristic, yet the future to which it spoke so promisingly seems more the subject of fond regret; one where to travel by road at high speed and in considerable comfort seemed not only possible, but within the bounds of social acceptability.

Arriving on the cusp of a new decade, 1970 was also a new frontier for the French Republic. Two years on from the bitter student demonstrations on the streets of Paris, France was looking to the future. Its post-war President had retired from public life, succeeded by a modernist who championed leading-edge technology, high-speed travel and large-scale public projects like France’s nuclear programme.

Either by happenstance or design, the SM would chime with this new frontier. As futuristic as Aérospatiale’s Concorde airliner, which in November 1970 took off from Toulouse to make its first Mach-2 test flight. Keen to be associated with such an emblematic project, President Pompidou would himself go above and beyond in Concorde prototype 001, taking in a short supersonic burst over the Bay of Biscay.[1]

No car is created in a vacuum and despite being the culmination of some of the finest minds within Citroën’s Bureau d’Études’, it was Citroën President, Pierre Bercot, who lent the SM his wholehearted support, without which it would not have left the drawing boards. Highly intelligent, independent in thought and unswerving in action, Bercot was far from a typical automotive executive. A man of culture, he appreciated poetry and fine art, counting classical pianist, Arthur Rubenstein as a personal friend.

Under Bercot’s direction, Citroën had grown into a massive conglomerate, acquiring Panhard et Levassor, truckmakers Berliet, Maserati, and entering into the Comotor joint-venture with NSU – lending critics to suggest that monsieur le President was at least as impulsive and risk-prone as Citroën’s ill-fated founder. Bercot’s Citroën was very much at the vanguard of technology and avant-garde design, so not only did he view the SM as a necessary step, he dismissed his critic’s objections as trivialities.

To his eyes, Citroën’s purpose was to aspire not only to the best that could be possibly contrived, but to elevate the customer’s aspirations, stating, “Citroën’s character is only fully expressed in the lowest and highest market segments.” With the advent of the SM, Pierre Bercot would put this philosophy to the ultimate test.

Image: influx

It might be convenient from a narrative perspective to suggest that the SM came about as part of a carefully considered product plan, but that would be inaccurate. In reality, it came into being, primarily at the behest of company president, Pierre Bercot, but at a more fundamental level from another man’s determination to prove a principle. Foremost amongst Quai de Javel’s talent was André Lefèbvre, a conceptual engineer of remarkable ability, creativity and foresight.

Lefèbvre had became frustrated with some of the voices within Citroën who questioned the carmaker’s continued adherence to the traction avant formula. Determined to prove the principle, Lefèbvre set out to demonstrate that a high powered motor car was capable of being driven by its front wheels, resulting in a series of high-performance short-chassis DS models. Both cognisant and in approval of Lefèbvre’s efforts, Pierre Bercot’s sanctioned a formal research programme, lending it the title, S-vehicle, headed by Jacques Né. 1966 would prove a pivotal year, since not only did Bercot initiate Projet G (1970’s acclaimed GS), but also sanctioned development of a production S-vehicle.

The highly unusual structure and operation of Citroën’s Bureau d’Études may have created a number of technical masterpieces, but it equally resulted in a number of serious operational drawbacks, perhaps the most grievous being the lack of a cohesive singularity of purpose. This was especially true when it came to engine development. Under Bercot’s leadership, despite Citroën’s advanced integrated hydraulic systems and sophisticated chassis dynamics, engines tended to be viewed as something of an afterthought; the prevailing perception being that Citroëns, be they lowly deux chevaux or patrician DS berlines, were poorly motorisée.

The powertrain team, led by Italian, Walter Becchia had created a number of vee-formation engines with both six and eight cylinders for Jacques Né’s S-Vehicles, but the costs of production were prohibitive. Also tried were high performance versions of Maurice Sainturat’s venerable in-line four, but costs again reared their head. At this point, Bercot concluded that the answer for his nascent S-Car lay outside the Rue de Théàtre, canvassing a number of carmakers who might be interested; Citroën stipulating a lightweight alloy engine of around 2.5 litres capacity, and a V6 layout, for compactness.

One of these carmakers being Maserati; Bercot making enquires with fellow-CEO, Adolfo Orsi in 1966. Within weeks, a prototype was at the Rue de Théàtre. Highly impressed by the speed in which the Italians could work, an order for a number of prototype engines was fulfilled, and quickly fitted to Né’s S-prototypes. Bercot wasted little time, negotiating an engine supply contract before anyone else had even got off the blocks. For Maserati, Citroën’s interest was fortuitous. Facing significant costs meeting upcoming US regulations, and with an ageing product line, the necessity for collaboration was becoming glaringly apparent. For Pierre Bercot however, it went deeper than a simple engine supply arrangement.

By 1968, Bercot had purchased the Modenese atelier in its entirety, leading some to view the Citroën-Maserati takeover not so much a symbiotic coming together, but simply Monsieur le President’s Victor Kiam[2] moment. For Bercot an equity stake would ensure Citroën had sufficient control over the supply chain – no small matter at Quai André Citroën and an entirely prudent one. But another imperative appears to have been more sentimental in nature. Far from the aloof technocrat he is generally portrayed, it seems Pierre Bercot had a genuine affection for the Modenese exotic carmaker, referring to them as “une grande maison.”

By 1967, Bercot and his Michelin masters were also engaged in advanced discussions with FIAT scion, Gianni Agnelli, and some chroniclers have suggested that the purchase of Maserati was aimed at furthering this ambition – Agnelli also known to have a soft spot for il Tridente. Cognisant however of the political ramifications surrounding a potential Franco-Italian merger, they fleshed out a collaborative deal where the Italian carmaker would assume control of Michelin’s 49% stake in Citroën.

By the close of 1968, the PARDEVI accord was complete. Bercot now President of a newly created holding company, Citroën SA, while Automobiles Citroën would administer the carmaking function, headed by new appointee, Claude Alain Sarre. With Pierre Bercot now more remote from the day to day running of the various car businesses he had worked so hard to combine, these developments would come at a crucial time for the S-vehicle programme.

Image: racingcars-wikidot

Quite naturally, the SM employed Citroën’s centralised engine-driven, high-pressure hydraulics for damping, steering, braking, levelling and attitude control. This highly innovative and technically ambitious oleo-pneumatic system was developed by Paul Magès and first employed for the rear suspension of the 1954 15 h model, prior to it being rolled out in fully interconnected form in 1955’s DS 19.

Assisting Magès on Projet S was Hubert Alléra, who had designed the hydraulically actuated gearchange for the DS. Suspension-wise, the car wouldn’t depart radically from existing practice, in fact a great deal of DS thinking (and hardware) was carried over – largely for cost reasons, but also because in the opinion of Jacques Né, not only were they strong enough to cope with the car’s additional performance, they were entirely appropriate to a car of its potential.

The major departure from previous Citroën technical practice was Magès’ radical DIRAVI (DIrection a RAppel asser-VI) speed-sensitive, self-centring steering, introducing, alongside the geometrically pure centre-point steering, an unprecedented level of control. Such was its directness, an unpowered system would have rendered the car undriveable.[3]

To alleviate this, Magès’ engineers developed a speed-sensitive variable servo, which provided maximum assist at very low speed (manoeuvring or parking) with a gradual easing of assistance as speeds rose, with zero assistance at high speeds when straight line stability was of greater importance. Coupled to this was powered self-centring, which came into effect once the handwheel was deflected from the straight ahead position, aiding high speed stability and reducing driver fatigue.

Engineers determined from their exhaustive tests of the system that the smaller movements required upon the handwheel with the DIRAVI setup combined with the ultra-quick steering ratio, saved important time during direction changes, making for quicker and safer manoeuvring.

Architecturally, given that Né was an André Lefèbvre loyalist, he would have been bound to uphold the definitive Citroën way of approaching matters. Furthermore, he was not operating with an unlimited budget, so either way there was a compelling case to be made for continuity.

Image: Citroen Press via thecarhobby

Hence, the SM body structure and chassis layout closely reflected that of the existing DS, with a large pressed steel punt-shaped base unit, to which the structural elements of the SM bodyshell were welded. One notable advantage of the DS layout was that the engine’s fitment well inside the wheelbase not only aided weight distribution, but allowed for a more favourable dash to axle ratio, which a fore axle FWD layout would have made impossible.

However, this layout, with the engine mounted aft of the gearbox and final drive, was not particularly space efficient, and despite the engine being tucked snugly against the bulkhead, there entailed a long frontal overhang – fortunately another Citroën tradition. A further advantage of this layout was a low polar moment of inertia, which aided stability and balance. All of these factors would entail that the SM was a larger car than strictly necessary, more so even than the more commodious DS saloon.

Image: The author

The SM also brought a new sophistication to something as prosaic as lighting, hydraulics being employed to provide automatic levelling for the six quartz halogen Cibie headlamps; the inner pair also turning in harmony with steering inputs. Following DS practice, the SM employed a pressure sensitive brake button, which operated the four wheel discs, the front brakes mounted inboard, alongside the final drive unit.

So, irrespective of how Citroën’s Bureau d’Études was acting, the technicalities of the SM would be Quai de Javel distillate in its purest form.

[1] Tellingly, Citroën UK’s Oct 13 1970 press release for the launch of the SM contained the following: “It can be said that the SM represents as marked a contrast between not only the DS and other cars of the Grand Touring class, but also as between the Caravelle and the Concorde.” (The Caravelle being Sud Aviation’s pioneering jet airliner from the 1950s). [Source:]

[2] Victor Kiam was a US businessman who became a household name in the 1970s fronting a long-running TV ad campaign for Remington shavers, which contained the immortal line; “I liked it so much, I bought the company”.

[3] The DIRAVI steering fitted to the SM employed a ratio of 9:4:1 with a mere two turns lock to lock. Magès and Né also envisaged a mechanically actuated active suspension system, which by 1975 was running in experimental prototypes, incorporating hydraulic control of roll and pitch. However, this hydro-mechanical system was deemed too complex and expensive to productionise, and was put on the shelf until such time as suitable electronic control units became available. The Hydractive system made its debut in the 1989 XM, reaching its series production apogee with the 1997 Xantia Activa model. [Source: Jan Norbye]


Sources and references:

Robert Opron L’Automobile et L’Art: Peter I Pijlman
Citroën SM : Jan P. Norbye
Citroën SM : Brian Long
Sa Majesté – Citroën SM : Peter I Pijlman/ Brian Cass
Citroën SM – Accidental Death of an Icon : Stuart Ager – ISBN 978-1-5272-5023-9
André Citroen – Engineer, Explorer, Entrepreneur – John Reynolds
Maserati- The Citroën Years 1968-1975 : Marc Sonnery

Author: Eóin Doyle

Co-Founder. Editor. Content Provider.

46 thoughts on “The New Frontier : [Part One]”

  1. Lovely article, well informed and educational with zippy story telling.

    The exterior design is, for me, the most beautiful and arresting car to have graced our roads, and the interior is just so louche and evocative of that modernist era. Alas it was, I think, misunderstood, overpriced (in the context or what the market valued at the time), and, under-developed in terms of some of the engineering.

    An article to lift the spirits in terms of subject matter and written execution. Thank you.

  2. Good morning Eóin. That two-tone colour scheme on the styling model is very striking from the rear three-quarter aspect. I’m surprised it didn’t feature on the production car. I’ve trawled SM images on Google and cannot find any examples of a two-tone car.

    I have always loved the SM for its clarity of conception and pure, uncorrupted execution. It may not have been a commercial success, but the automotive world was enriched by its existence. What follows, therefore, might be regarded as blasphemous, so apologies in advance to anyone who is offended!

    The uptick in the window line, or rather the falling line before (and after) the uptick, is one aspect of the SM that I cannot quite get to grips with. In side profile, it makes the rear of the car look somehow weak and undersized compared to the front, especially when it’s sitting low on its suspension. The imgur app is misbehaving this morning so I cannot illustrate what I mean with a photo.

    I might commit an act of heresy later and play with the SM window line to see if I can ‘improve’ it. Have your brickbats at the ready!

    1. I agree with you, Daniel. I love the SM, but have never particularly liked its design from the B post rearward. It’s too droopy and fussy. Having said that, for me it always looks worse in photographs. On the very rare occasion I’ve seen one in real life* I’m always captivated by how sleek and curvaceous and generally gorgeous it is.

      * In the olden days when we could travel, whenever I was near Waterloo Station in London I’d try to make the time to visit one of the nearby streets where an SM, DS and BX live. Presumably the same owner!

    2. If they all belong to the same individual or household, the neighbours must all be either car enthusiasts or non-drivers!

    3. I didn’t think it was possible to get that many parking permits so my guess is that they own more than one house on that street. Either that or they pay their neighbours for their right to park…

    4. Laurent: Whatever the situation may be, I think it’s rather unseemly to be speculating upon it on a public forum.

    5. Unseemly? I’m only commenting on what I see out on the the street, i.e. in the public domain. Actually down my neck of the woods there is one street where I once counted three Range Rovers, and five (five!!!) Volvo XC90s all parked at the same time. So another possibility here is another weird case of keeping up with the Joneses within a rare cluster of Citroënists.

    6. Maybe you were out on the street in an unseemly manner? Which worries me as it sounds like we live near to each other. I do wonder whether the street with three Range Rovers and five XC90s could be my street, especially if it was children’s football at a weekend…

  3. Right, I’ve got my tin hat on, so here goes. Original SM:

    Waistline raised, straightened and extended to tail:

    Above plus rear hatch adjusted so that the edge of the glass (rather than the shut-line) visually connects with the kink in the trailing edge of the rear side window:

    Hatch adjusted further so the glass aligns with the lower DLO line:

    Kink removed from rear side glass:

    Time for me to beat a hasty retreat, I think…

    1. Good Morning, Daniel. Interestingly, you’re getting close to the R25 hatch treatment in that last version…

    2. I was afraid someone would say that, Michael. 😩

    3. Agree with John, and Michael, … the latter versions gradually morph in that other Opron design, the R25. I’d still stick with the original.

    4. I love your photoshop renderings, Daniel! On this set I really like the first one. I never realized how much the beltline drops on the SM until today. Risking heresy accusation, I like your proposal much better than the original. The last iteration looks quite Fuego-esque 🙂

    5. Good morning Richard. Perhaps I’m simply following Robert Opron’s train of thought?

    6. In the original version there is not so much parallelism – the lines are supposed to conververge somewhere behind the car which is more dynamic than if they stay parallel. Someone once said that the story of car design is in part the change from lines tilting back to parallel to tilting forward. The SM is a late example of lines tilting back.

  4. you’re a good man Daniel, and we’re indebted to you
    for all sorts of insights and treasures and remarkable
    perspicacity, but you’re really tempting fate here.
    actually I remember you doing something similar
    with the E-type, what an outrageous iconoclast!

    1. That last one is almost there – move the B-pillar forward a touch, push it upright, and then you can add the rear doors….

  5. Thanks all, pretty much the reaction I expected. I think the first revision (second photo) makes the rear half of the car look more substantial and better balanced against the front. The further revisions make it progressively less SM-like, although the last iteration, perhaps with a more inclined C-pillar, is the most coherent of those three.

    Thank you, Lorender, for your kind (and lyrical) words. Happily, there are no sacred cows here at DTW, at least of the automotive variety!

  6. I love the droopy window line and pinched rear of the SM – it looks like it is being stretched out, and warped by perspective.
    In my opinion, it really works as a four door too, and i would give an arm and a leg to own a chapron SM opera.

    straightening it out makes the shape less organic, and removes some of the elegance.

    1. Other views are, of course, not only available, but welcome on DTW!

  7. I’ve said it before, the rear “face” of the SM needs to be lifted up a notch. The bumper needs to be lifted up to where the light bar is, and the lights needs to be lifted up above, preferably a horizontal light bar mounted on the hatch with room for the number plate in the middle, and with big amber turn signals in place of the chromed “horns”.

  8. Is Sean Patrick still on here? I used to love seeing his SM a couple of streets away from my house but sadly it or he seem to have moved on. And there’s no obvious SM replacement parked there, so I suspect it might be him.

    1. I’m local too and I miss seeing that car there. I haven’t seen the Nissan Cube for a while either, but I thought the camper van was his and that hasn’t moved for a while.

    1. Weirdly, I really like the one with the reverse-rake rear screen!

    2. Now thats an interesting article – nice to see the actual experimentation they did back in the day, but i can see why they eventually dropped changing the body too much in the end.

      I tried keeping the styling sensibilities of the day in mind, so its nice to see that i was thinking in the same lines as the actual designers.

      The reverse rake DS is pretty cool, but i would prefer it with the SM rear window compared to the more “jet age” upswept one by Jacques Charreton.

      Also – the early curvy SM model with the Matra 530 face looks a bit like the curvy one i made up top, with its window and beltline drooping down in the middle (only theirs was more extreme)

    3. Jacques Charreton’s renders are fascinating, especially insofar as, from my understanding, Projet L was not intended to directly replace the DS. The early ‘Curvy’ styling model you refer to above is documented in some reference books as being based upon a proposal from Bertone and carried out by some unknown chap by the name of Giugiaro.

  9. I absolutely adore the SM. It was one of the few cars my girlfriend liked as well, even more so after I pointed out that it’s name were here initials. She insisted on us buying one at some point, but sadly this never materialized as she passed away in November 2018.

    I love the design, especially how the wide front and narrow rear give the car a certain shape that leaves no doubt to which wheels are driven. The rear end is a little too busy, too much going on there. I’ve seen quite a few people having a go at restyling the back end, but still prefer the flawed original. Maybe that’s the mark of true artistry.

    1. My condolences for your loss, Freerk. I am inclined to agree with you as regards the SM’s ‘flawed’ derriere. Sometimes we need a little sand in the Vaseline, so to speak. Allegedly, it was Jean Cadiou who insisted upon semi-covered rear wheels on all Citroens – it was intended to underline the ‘Traction Avant’ layout – a holy writ at Quai de Javel.

      On the subject of the ‘Waterloo SM’, I recall seeing it there as well – quite the sight as one was emerging from one of the several watering holes in the vicinity.

  10. In the Roupell St cars, there seems to have a long standing Citroen connection in the area. When I worked around the corner c.1985, there was a garage under the arches (Waterloo East Station) specialising in the Traction Avant, at the junction of Roupell St and Cornwall Road. When I lived in the area c.2000, I remember “proper” Citroens being parked in these few streets. Correlation is not causation etc, but it does make mw wonder…

  11. I think we should remember that not only were Citroen’s designers in some ways honouring the Streamliner era of the mid-1930s, but also (and no small item this), referencing the the lines of the DS, which of course also embodied this falling line motif – very much a Citroen design leitmotif, as we know. If you view the SM in this light, it makes perfect sense – not that the SM requires much by way of explanation in my view anyway.

    1. I think you’re right, Eóin, context is very important here. I’ve thought a lot about the SM following my Photoshop experiments yesterday. My criticism was that the rear half of the car appeared ‘weak’ in comparison with the front, but perhaps that makes sense in the context of Citroën’s ‘traction avant’ tradition. Are the falling lines, narrower rear track semi-concealed rear wheels intended to reinforce the impression of that the SM is ‘pulled’ by the dominant front end? Or am I attempting to read too much into it?

    2. Daniel: no, you aren´t over-reading it. The car´s shape has meaning based in fact. I had the good fortune to see an SM being driven at top speed on a runway.

    3. Daniel, that’s kind of what I tried to clarify here, but Eóin has a more eloquent way of explaining it. Richard, I’ve never seen an SM at top speed. Must be a sight, but then again slower speed might be preferable, as I can watch it a little longer 😉

    4. Hi Freerk. I was actually influenced by your perceptive comment about the driven wheels and should have acknowledged as much. Apologies for my oversight.

    5. I recall a very wet night some years back, seeing a white SM zoom past on London’s Euston Road. It was quite late, so the traffic was light, and the SM was not hanging about. It was a memorable (and quite evocative) sight.

      I have been fortunate enough to travel as a passenger in an SM from Streatham South London to Horsham in Surrey. A memorable day, not just because the weather was atrocious (the tail end of a horrendous storm), nor simply because the SM ran stable and true despite the conditions, both there and back (the owner wasn’t hanging about), but also because it was the very same day that DTW went live for the first time. The SM was magnificent – and the sound of that Maserati engine being given full voice lives long in the memory.

    6. What a wonderful memory, thank you for sharing Eoin. If only…

Leave a Reply to Daniel O'Callaghan Cancel reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: