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CitroŽn SM

Autocar w/e 7 September 1974

Elegant complexity

10,000 Miles
By Ray Hutton

The CitroŽn SM can claim to be the world’s most advanced car. Is all the complication worth the cost?

After a long-term test which has encompassed two different SMs and journeys ranging from long Continental trips to 50 mph-limited commuting, we believe that it is.

This story really begins last summer when Autocar entered a CitroŽn SM in the BRSCC’s first Tour of Britain. Howden Ganley and I drove it.

Our result was nothing to get excited about; the car had proved less competitive than we had hoped and more difficult to handle than we had anticipated. I remember asking Howden what he thought we had learnt from the exercise. His answer was succinct: “Well,” he said, “Now we know why people don’t race CitroŽns”.

With hindsight, it was a pretty rotten thing to do to a fine car, which, like all CitroŽns had been designed with a “clean sheet” approach to meet certain specified conditions. Those included the need for quiet, high speed cruising, a superbly comfortable ride over all sorts of surfaces, and a very sophisticated power steering system. But they did not include racing.

In our original road test of the SM (Autocar 10 June 1971) we described it as “technically the world’s most advanced car”. One of our intentions had been to find out how reliable its many complex systems would be under the stresses and strains of competition as well as in normal use. On the Tour

they had given no trouble and a few weeks later, denuded of its roll cage and with the dents knocked out, the car came back for us to gain further experience with it under more typical road conditions.

It was running well, though both engine and gearbox were noisier than they had been originally.

From the long-term test point of view the snag was that very little was known of this car’s history; it had been prepared as a Group 1 rally car by the CitroŽn Competitions Department in Paris and had seen action as a practice car for the Moroccan Rally (which an SM won in 1971). Furthermore, it was not the latest model as it had the triple-Weber carburetted engine which had been superseded by the Bosch electronic fuel injection version. CitroŽn Cars Ltd. very generously agreed to the long-term loan of a never-raced-nor rallied Injection SM in its place.

It had done 4,000 miles as a press demonstrator; we aimed to add a minimum of another 10,000.

Actually it could not have come at a worse time. It was the beginning of December and the height of the fuel shortage around London. None of us were using cars for long journeys if we could avoid it and those who would normally have been so keen to drive the SM were squabbling over our Renault 5 and Fiat 127. Experience suggested that we would be unlikely to get more than 15 mpg around town, though even at that rate its big tank gave it a useful 300-mile range — providing you could find somebody to fill it up. But then there was the 50mph limit which succeeded in its intention of boring us away from the motorways, and at which speed the SM would not run cleanly in fifth gear. In any case it seemed anti-social to be using a car so obviously designed for the enjoyment of motoring in those petrol-starved times. The miles went on slowly.

From a driveability point-of-view I am not convinced of the advantages of fuel injection. The SM Injection Electronique (EFI) had excellent throttle response when accelerating and none of the “hunting” at low speed and idle that is associated with some electronic systems, but does not have the reassuring shut-off when the throttle is lifted like an old-fashioned carburettor engine. It had an occasional light-throttle hesitation. Furthermore, it turned the SM’s already frighteningly complicated underbonnet scene into a mechanic’s nightmare with its system of air ducts, filters, intakes and banana-shaped inlet manifolds. Having spent a frustrating hour removing the six sparking plugs on the carburettor car (the sixth was totally inaccessible) I was glad that the fuel injection version did not share its tendency to foul its plugs in traffic. In fact, cold starting and subsequent drive-away were always excellent. The rich mixture control is automatic.

Our road test of the injection SM (Autocar 23 August 1973) had suggested that apart from maximum speed (4 mph up) as a result of higher gearing, performance was slightly down compared to the earlier model. Figures taken with our long-term car at 11,000 miles, published here, show an improvement over the original injection test car in step-off, though as a whole they are still a little slower than the first SM that we tested. Such observations are really only of theoretical interest because the SM is not a car that is bought for ultimate performance alone.

Above: The EFI test car was trimmed in expensive leather. Seats are comfortable and infinitely adjust able, but they lack side support. Facia is simple and features multi-purpose warning light system (inset). The big red light in the centre is additional warning of hydraulic failure, loss.of oil pressure, or overheating. The button is to check that these warning lamps are working.

Performance is in any case remarkably good for a car that weighs over 30 cwt and is powered by an engine of only 2.7 litres.

Altogether the SM is an odd amalgam of characteristics. Its startling, super-streamlined body couldn‘t be anything but a CitroŽn 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 on the other hand, 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, and belies the transmission’s distant location from the cockpit. 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.

These things and others, therefore, give the CitroŽn SM a truly unique character. It is not everyone’s cup of tea. Certainly it takes some getting used to, which is why we encouraged anyone driving it for the first time to do a longish journey which would give him time to adapt to its peculiarities and also use the car under the conditions for which it was primarily intended. Not everyone returned convinced. For me it was a taste quickly acquired, like eating an avocado pear for the first time: you are unsure at first, come to appreciate its subtle qualities and then can’t have enough of them.

The thing that needs acclimatization (and can catch you out when you come back to the SM from another car) is the very high geared steering. It is like driving a go-kart; at first one tends to over-steer and over-correct, and progress is twitchy. When mastered, it is one of the best features of this remarkable machine. Mechanically it is one of the most complex of the car‘s systems and its method of operation is unique. It is perhaps worthwhile to take a little space to examine what Citroťn’s engineers set out to do and how successful they have been in meeting the object.

The SM is heavy, and has a substantial front weight bias; it has front-wheel drive; and big tyres (205/70 VR 15 Michelin XWX on the injection version — the same as we used on our “racer“). Power steering was clearly essential. It needed to be light for low speed manouevring since the SM is a big car with an unusually long wheelbase. They wanted to have the degree of positive control that only a racing car with very high geared steering could attain. Two turns from lock-to-lock was judged to be ideal, but with the light control envisaged for parking, would make the steering far too sensitive at high speeds. Their solution was to build an artificial “feel” that increased with the speed of the car and they used ideas from aircraft control systems to achieve it.

So, as the speed increases, the resistance at the steering wheel is increased, giving it the feel of an unassisted set-up with the advantage of very high gearing. An adjunct to this is that the steering has servo self-centring. At low speed or when stationary this means that the front wheels automatically return to the straight-ahead position, though any hand movement by the driver causes a positive reaction in the hydraulic valve system which then assists his movement like a more conventional power-steering arrangement. Furthermore since all the “feel” is artificially created, the steering wheel is very largelyinsulated from kick-back over bad surfaces and some of the less favourable characteristics of front-wheel-drive.

Above: If it breaks down, call a plumber … Underbonnet view is daunting, with V6 engine buried beneath injection system and inlet manifolds

The mechanics of this system have been dealt with in detail in these columns (Autocar 21 January 197l). It works exceedingly well and plays a very large part in the confident and accurate way that this large car can be rushed through twisting roads like a sports car. Many of the less attractive characteristics of the front wheel drive layout are disguised by it under normal conditions, including the understeer and its tendency to pick up and spin the inside front Wheel. Progress that seems very dramatic from the outside feels very secure from within, and as a result one often finds that one has entered a corner much faster than expected.It contributes to the car’s excellent “hands off’ straight line stability.

The self-centring makes the car surprisingly easy to park at the kerbside, for once a gap has been entered, straightening up is simply a matter of letting go of the wheel between each backward or forward manoeuvre. There are a few disadvantages too. Even when used to it, in town it does need a fairly delicate approach, which not everyone is able to muster. It is a quirk of the system that it is still a little too sensitive around the immediate straight-ahead position. Correct adjustment to the steering wheel’s straight-ahead position is critical (and quite easily done by moving the rack; a single bolt job). We found that out on the Tour of Britain when the steering was deranged by an argument with the Armco at Oulton Park. A bottom wishbone mounting was slightly bent and I remember driving down the M6 applying perhaps one-eighth of a turn of lock to keep the car straight; a job that became increasingly harder on the wrists as the car went faster.

More serious though was my discovery that the very steeply cambered roads that are found in some parts of France had the same effect (with the steering in good order) and that driving fast along them became physically tiring as one struggled against the steering to keep the car on a straight course.

I mentioned manouevring a while back. From the steering point of view this is easy, but the very wide front and long sloping nose means that like the DS Citroťns it is hard to judge its not inconsiderable size (16 ft long and 6 foot wide) when turning in confined spaces. My colleagues are fond of telling stories about the many people who have misjudged the gates of the office car park with DSs. I made the mistake of boasting that I didn’t understand the problem; I had never had any trouble with them. The very next morning I confidently swung the SM through the gateway only to hear a sickening clang. In fact, all I had done was to break off the thick rubber facing on the bumper that wraps round the nose, but it illustrated just how close I had been judging things without realizing it. The SM is longer and wider than it seems.

Above: the SM EFI outside the walled town of Carcassonne, en route for Spain.

In another make of car the suspension and ride would be remarkable. Sufiice to say that the SM uses the well-tried CitroŽn interconnected hydropneumatic struts which make it self-levelling and has ride comfort second to none.It has a three position ride-height adjuster to give it adequate ground clearance for any sort of bad road.

As with the DS and GS, bumps and bad surfaces are ironed out with ease, and only hump-back bridges and the like catch the suspension out. For reasons that are not entirely clear to me, its performance over cobbles is less impressive, a sort of uncomfortable patter being set up from the rear wheels. Road noise is high, being particularly sensitive to bump-thump from cat's eyes.

I took the car to the Spanish Grand Prix at Madrid, which involved all aspects of motoring from rock steady cruising at very high speed on motorways (120 mph is quiet and comfortable; roads, laws and traffic permitting), to snow-covered mountains in Andorra. Fast main roads with long sweeping curves are the SM’s forte; for much of France there can be few ears quicker. On slower, sharper corners its biggest disadvantage becomes apparent - the amount of roll. The car really isn’t happy being driven through a series of lacets with verve. No sooner has the suspension caught up with the car’s attitude for one corner than it is unsettled again for the next. The result is a lot of bucking around to accompany the inevitable tyre scrub and a very uncomfortable time for your passengers, who are not helped by the lack of sideways location in the seats. In general, it is better to adopt the rear-wheel drive technique of “straightening out“ corners as much as possible to keep the roll to a minimum.

Hard acceleration produces a noticeably nose-up attitude but under heavy braking the anti-dive geometry reduces the opposite reaction. I fid the DS-type no-travel brake button very reassuring for a fast car and the all-disc set up proved very consistent in normal use except on one occasion when unexpected front wheel lock on a slippery country road caused me some anxious moments. Out of curiosity I tried to reproduce this in tests at MIRA and found that after four or fie repeated heavy stops the rear wheels did have a tendency to jack up and slew sideways as the fronts locked.Under normal circumstances, however, the brakes are without fault.

One could not fail to be impressed by the SM‘s performance on our trip to Madrid. By the effortless way that it ate up the miles, with virtually no wind noise and just the dull drone of the engine in its high fifth gear; the impression from within is in some ways more like a small aeroplane than a car. There is the feeling of insulation from the outside world, yet with a solid aura of security and the confidence of complete control. I was not surprised to hear from ‘CitroŽn that a large percentage of the 400-plus British customers for SMs use them for long journeys, particularly on the Continent. One such customer is Mike Hailwood, who has had his SM for three years, yet previously changed his cars on whim every few months. “It’s nice and comfortable on main roads — I just like it", he says, confessing that he doesn’t look after it very well and that it had been reliable “except when there was no anti-freeze in it last winter - that messed it up a bit.

Strangely enough, ‘the water system‘ gave me some cause for alarm on the return from Spain.

Slightly higher than normal water temperature and the need for three or four pints of topping up water a day suggested either a leak (which wasn’t visible) or head gasket trouble. When safely back home it was found to be the latter - a problem not unknown previously and which had resulted in a new design of gasket. Otherwise, the 3,200 mile round trip was marred only by a bad engine-induced vibration,  irritatingly transmitted through the chassis at a steady 4,500 rpm, which represents just over 100 mph in fifth gear and 80 mph in fourth. Apart from discouraging cruising at these otherwise convenient speeds, this was no doubt one reason why several minor bolted-on components like door and boot locks and one headlamp mounting came adrift during the trip.

Vibration also tended to cause the adjustable steering column to slip to its lowest position. In and out and up and down column adjustment is only one of the factors which go towards producing a perfect driving position for everyone. The seats can be adjusted for height front and rear, and thus for rake as well, while the backrests are,unusually, hinged half way up instead of from the base. This looks as if it ought to be uncomfortable but in fact provides the fine adjustment to get the driving position just right. The thick, soft head restraints are also fully adjustable. Stuart Bladon has an irrational fear of headrests and the like and ejected them before even sitting in the car when he took it to the Geneva Show. A pity, for had he tried the SM’s, he would have found them most comfortable; both for supportingthe driver’s neck and as a pillow for the front seat passenger.

Above: The SM is a big car. Its streamlining is good for aerodynamics, less so for visibility. The suspension is adjustable for height; here it is at the lowest setting

The test car differed from our Tour SM in having leather, rather than nylon cloth-covered seats. These add a hefty £258 to the price, but their smoothness only accentuates the lack of sideways location, and the far from ideal placing of the unusual socket-clasped Toric seat belts did little to help.

Though a driver and one passenger could travel all day in the SM without getting uncomfortable - and arrive fresh at their destination — carrying four people for any distance is less satisfactory.  The rear seats are well upholstered and nicely shaped but headroom and, more particularly, leg room are a problem, though rear passengers’ feet can be tucked under the front seats. In recognition of this, the front passenger‘s seat has less adjustment than the driver’s. Even someone of average height feels more comfortable with the passenger seat near its rearmost point.

One is forced to concede that in terms of packaging, the SM does not come out very well. Like many American cars of similar (and bigger) dimensions it is really only a 2+2. Neither is the luggage space over-generous. The big spare wheel occupies a great deal of boot space. We managed to accommodate all our luggage plus typewriters and a lot of camera gear in it for the Spanish trip, but only by using a number of soft bags instead of suitcases. The boot leaked. Inside stowage space for oddments is provided by some useful side bins (in the doors and at the rear) and a disappointingly small facia locker.

Though it looks very futuristic at first glance, the facia is actually quite straightforward. It is possible to adjust the steering column to the point where the working range of the speedometer and rev counter are not visible.  The third matching oval dial has no less than l4 warning lights, for everything from indicators to hydraulic failure and a test switch so that you check that the bulbs are working in the more important ones. The three smaller gauges at the centre are for water and oil temperature and fuel, the latter being very vague (the same system flashes the low fuel warning light on bends with nearly half a tank left). The heating and ventilating controls are nice to use and easy to understand; air distribution is good though the heater isn’t all that powerful. Our car had the optional air conditioning — pleasant, but £291 extra. On the centre console, trimmed like the facia with a bronze satin-finish aluminium, is the switch for the electric windows which are maddeningly slow in operation, the handbrake, and the radio slot. I was disappointed to hearĽ that cassette players should not be mounted vertically; we fitted a Radiomobile 330 radio which was reported on in the issue of 13 July 1974.

Lighting, wipers and indicators are dealt with by finger-tip stalks. The bank of six quartz-halogen lights is yet another SM novelty and they too are self-levelling as well as the inner pair moving with the steering. The spread of light that they produce is fantastic, though unfortunately they prove very difficult to adjust satisfactorily. One of the toughened glass headlamp covers was smashed by gravillons on my return through France. The wipers — which have two speeds, intermittent (variable by rheostat) and not fast enough — are, however, really not up to the performance of the car.

No one would expect a car of this price, let alone of this complexity, to make concessions to the home mechanic. Servicing and repairs are a specialised business for which mechanics are specially trained. 25 of Citroťn’s 180 British sales outlets are officially “SM dealers”. During our tenure the sight tube on the big green canister which contains all the hydraulic fluid never dropped below “maximum”. Access to oil and water fillers, washer bottle, even the distributor and alternator is not bad. Checking and topping up the battery is more awkward and if it needs to be removed it has to be taken out through a hatch in the right hand wheel arch. Aside from those items mentioned we had no troubles or failures with the car. Front brake pads needed to be renewed at 6,000 miles and again at 14,000; at which point it also needed a new pair of front tyres. These running costs are included in the accompanying table. To put the overall fuel consumption figure into perspective, the average for the Spanish trip was 20 mpg. General use, including commuting, varied between 15 and 19 mpg with an all-time low for 150 miles around London of 10.5! Overall. the car proved more economical than the carburettor SM.

Only the privileged few can afford a car that costs nearly £7,000. But even leaving price aside, the SM is not for everyone. Opinions among our testers range from great enthusiasm to “no thanks”. It is a true Grand Touring car and needs to be used as such. Around town and in little country lanes it is rather unwieldy and this country made worse by being left-hand-drive. CitroŽn acknowledge that they lost a lot of potential customers when plans for a right-hand-drive version were dropped.

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. 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.

Above: How it started. The Group I carburettor SM on a stage of the 1973 Avon Motor Tour Of Britain


Maximum speeds

mph kph rpm

R/T Staff R/T Staff
Top (mean)
Top (best)
Standing 1/4 mile

R/T 17.1 sec
81 mph

Staff 17.1 sec
81 mph
Standing kilometre

R/T 31.0 sec
109 mph
Staff 31.0 sec

Fuel Consumption

Overall mpg
17.9 mpg (15.8 litres/100km)

18.1 mpg (15.6 litres/100km)


True speed mph
Indicated speed R/T
Indicated speed Staff
Time in seconds R/T
Time in seconds Staff

Speed range, Gear Ratios and Time In Seconds

Top R/T
Top Staff
4th R/T
4th Staff
3rd R/T
3rd Staff
2nd R/T
2nd Staff


Running Costs

Life in miles
Cost per 10,000 miles
One gallon of 5-star fuel average cost today 55p
One pint of top-up oil average cost todau 29p
Front disc brake pads (set of 2)
Rear disc brake pads (set of 2) 12,000
Michelin XWX 205/70VR-15 tyres (front pair)
Michelin XWX 205/70VR-15 tyres (rear pair) 35,000
* Service (main interval and actual cost incurred)
Running cost per mile
Approx. standing charges per year
** Insurance
Price when new
Trade in cash value (approx.)
Typical advertised price (current)
Depreciation (over 12 months)
Total cost per mile (based on cash value)
** Insurance cost is for 34 years old driver, with £65 per cent no claims bonus and with car garaged in Byfleet, Surrey.  Subject to compulsory excess of £200.  Named drivers only.
* Estimated with the help of Eurocars Ltd. as typical; repair of blown head gasket at 14,000 miles not included (see text)

© 1974 Autocar/2015 CitroŽnŽt