Citroën SM- The Car that Looked like a Spaceship

The Citroën SM was the most intelligent car made by Citroën, that most intellectual maker of cars. Not only did it look like nothing else, the SM incorporated design innovations which are still filtering through to the mass manufacturers over fifty years later.

The Citroën SM was a 1970 three-door hatchback coupe version of the Citroën DS, the revolutionary 4-door Citroën which was released in 1955. It featured a V6 Maserati engine which provided enough power to take the DS ideas even further.

And it looked like a spaceship.

A picture of a long sleek white Citroën SM which looked like nothing else on the road as the rear wheels are hidden.
The Citroën SM looked like nothing else on the road

How many Citroën SMs were made?

There were only 12,960 Citroën SMs made. This is a small run for such an expensive car to develop.

What does the SM stand for in the name Citroën SM?

There is much debate about what the SM stands for in the name Citroën SM. The name of the divine 1955 Citroën DS is actually a pun on the French for goddess: déesse. So you might assume the SM might stand for Sa Majestie (her majesty).

A shot of the rear wheels which were enclosed for improved aerodynamics.
The Citroën SMs rear wheels were completely enclosed for improved aerodynamics

However, it was Citroën’s acquisition of the Italian car maker Maserati that made the SM possible as Citroën was really buying the company for Maserati’s V6 engine. The factory referred to the new project in 1961 as “Project S”.

So it is more likely that the S stood for a Sports version of the DS, and the M stood for Maserati. Another theory is that it stands for “Systeme Maserati”.

The interior had an oval wheel and oval gauges.
The interior was also in the modernist idiom.

Who designed the Citroën SM?

Robert Opron designed the Citroën SM. He also designed the DS’s successor, the CX, the Simca 1100, and the Alpine A310.

The Specification, engine and interior.

Just like its sister the Citroën DS, the Citroën SM had powered high-pressure hydraulics that served the steering, the brakes, the gearchange and the self-levelling all-independent suspension.

It had disc brakes, Michelin X radial tyres, front-wheel drive and self-levelling headlamps that actually swivelled to follow around corners.

A picture of the headlights, which swivelled to follow round corners.
The Citroën SM’s headlights followed you around corners

However, the USA version had to make do with ugly round headlights due to federal legislation. The SM also fell foul of the 5 mph bumper regulations introduced in 1974, so after just two years on the market, the car was banned from America.

The round headlights of a Citroen SM
Proving that the law is an ass, Citroën was forced to fit round headlights.

Furthermore, it had all-round disc brakes, and even carbon-reinforced glass fibre wheels were offered as an option. Yes, plastic wheels!

The engine was a Maserati V6 of 2.7 litres. This small capacity was due to the French luxury tax, the puissance fiscal. Later SMs had 3-litre engines. The aluminium Maserati engine was notably lightweight at 140 kg (309 lbs) and mounted behind the front axle.

A Citroen SM Engine compartment
Those green spheres contain pressurized nitrogen for the suspension, steering and brakes.

This resulted in good weight distribution. Because it was made on the same tooling as the Maserati V8, the V6 had the same angle between the cylinder banks: 90 degrees. This is not ideal.

With three Weber carburettors, the 2.7 made 168 hp (170 PS, 125 kW), and the 3.0 litre developed 178 hp (180 PS (132 kW).

A red Citroen SM with the bonnet raised, in a car museum
Later Citroën SMs had 3-litre Maserati V6 engines

Some of these engines tended to self-destruct at around 60,000 miles due to timing chains stretching and valves hitting pistons. This reputation inhibited sales.

The interior was also dramatically styled, with bucket seats made of rolls of upholstery.

This picture shows the Citroën SM headlights and number plate, which were covered with a glass windshield.
The Citroën SM headlights and number plate were covered with a glass windshield

How was the Citroën SM developed?

Some background is necessary. It is hard to explain today what an impact the Citroën DS had on the motoring public in 1955. At a time when appalling “sit up and beg” monstrosities such as the cart-sprung Ford Prefect were being foisted on the unwitting public, Citroën unveiled a car that looked like nothing else.

A shot of the 1955 Citroen DS
The Citroën SM’s older sisters: the Citroën DS and 2CV

Its technology was breathtaking, and far exceeded that of the contemporary Mercedes Formula 1 racing cars. It featured powered high-pressure hydraulics that served the steering, the brakes, the gearchange and the self-levelling all-independent suspension. It had disc brakes, Michelin X radial tyres, and front-wheel drive: all years before they were generally accepted.

The drag coefficient of the sleek body was the same as a Porsche sports car. Some of the features such as the swivelling headlights that follow corners are only just now being offered by rival car makers 66 years later.

The Citroën DS was perhaps a car too far. Instead of inspiring rival designers to take on the challenge, the DS was misunderstood, derided and ignored by an industry that would prefer to produce tin boxes for the masses.

However, Citroën sold 1,455,746 examples to its believers.

If the Citroën DS had been a car too far, then Citroën went even further with the 1970 Citroën SM, the three-door hatchback coupe version of the DS that is the subject of this article.

It featured a Maserati V6 engine with 178 bhp transmitted through the front wheels. For most front-wheel drive cars full application of this kind of power would result in torque steer: you feel a writhing and juddering, with the steering wheel tugging from side to side.

 Citroën dealt with this in their usual analytic way by having zero kingpin inclination, zero camber and zero caster. These various tilts are incorporated into ordinary cars’ front wheels, partly to provide steering feedback.

But in the SM there was no steering feedback: the driver just steered and the car went the way it was pointed. The DIRAVI adaptive, speed-sensitive and self-centring steering saw to everything (“Direction à rappel asservi” means “steering with controlled return”).

Even hitting a pothole at high speed would not be felt. And if a rear wheel was destroyed in a pothole, the SM could continue on three wheels.

And there were plenty of potholes in Uganda, the nation that had the great misfortune to be ruled by Idi Amin, the Citroën SM’s most infamous owner. Amin joined the British Army as a cook, rose through the ranks to general and then took power in a coup.

Up to half a million people were killed under his regime, he had his ministers thrown to the crocodiles of Lake Victoria, and he was accused of eating his political enemies: yes, cannibalism.

The New York Times reported this:

“Idi Amin did what he did in a transparent way: the mayhem and the horror, but also the famous photograph of white businessmen forced to carry him on his chair; his satirical wedding ceremony in front of a huge portrait of Queen Elizabeth II of England; his repeated claims to the throne of Scotland. When asked about allegations of cannibalism, instead of denying it he answered: “I don’t like human flesh. It’s too salty for me.”

New York Times August 21, 2003

Amin’s most inexplicable passion was for his Citroën SM, which he drove every day. And here is a disturbing fact for admirers of this rational car: this most irrational of men, a cannibal dictator in a country without many roads owned not just one SM, but seven of them.

A red Citroen SM showing the huge glass tailgate
The huge glass tailgate of the SM.

Other notable owners were the USSR’s petrol-head president Leonid Brezhnev, author Graham Greene, Bill Wyman and Charlie Watts of the Rolling Stones, and Emperor Haille Selassie. Oh, and Jay Leno.

A shot of the front of a white Citroen SM
The view that most 2CV owners got of the SM: the overtaking view

How much is a Citroën SM worth today?

A Citroën SM is worth today between $17,000 and $62,000. And they are worth an average of $42,130 (source:

How many Citroen SMs are left?

There are 29 Citroën SMs left in the UK. It’s unknown how many Citroen SMs are left on the road in the USA or other countries.