The Citroën 15-Six, colloquially known as “Quinze,” was the top of the automaker’s car range for 18 model years with remarkably few changes. It was the last French-made straight-six and also the first car to feature the famous hydro-pneumatic suspension.
But first, let’s look at Citroën’s context and the Traction Avant range in a bit more depth…
Getting Traction: André Citroën’s Testament Car
The background of the Traction Avant’s birth is one of total chaos. André Citroën just had the main Javel factory completely re-built in 1933, as car sales plunged due to the Depression. The RWD “Rosalie” range was not selling very well and the creditors were panicking, but Citroën was a betting man. He wagered everything on the Traction, which was rushed to production in a little over a year.
The new car would be a cocktail of the most up-to-date technology: hydraulic brakes, unibody construction, no running boards, torsion bar suspension, brand new overhead-valve engine driving the front wheels, automatic gearbox – all packaged into a beautifully-proportioned, aerodynamic (for 1934) low-slung saloon designed by Flaminio Bertoni.
That was the plan – Citroën’s high-stakes bet. And he almost pulled it off. At the last minute, he nixed the troublesome automatic gearbox and had his engineers design a traditional 3-speed in three weeks. The Traction quickly entered production, hit the dealerships in April 1934 and soon evolved into two main ranges – the smaller “7” and the larger “11” – complete with two-door convertible and coupé varieties, as well as limousines.
These early cars had numerous flaws: universal joints would break, unibodies were too weak, suspensions too fragile, engine mounts inadequate, etc. Sales quickly nose-dived after the initial summer boom; the many repairs under warranty and constant production changes were further sinking Citroën, which had stopped selling the Rosalie – denying itself those customers who were weary of the new car.
André Citroën thought he still had an ace up his sleeve: the 8-cyl. Traction Avant “22”. He ordered the car in pre-production, added it to the brochures and put a few on display at both the Paris and Brussels Auto Shows in October and December 1934. The Citroën 22, with its 100 hp V8 made from two 11 CV blocks, was purported to reach speeds of 140 kph (85 mph) “in complete safety”.
A few prototype saloons, and at least one limousine, one roadster and one coupé were photographed in 1934. They have all since vanished – not a single 22 has been seen in several decades.
On December 21, 1934, the company was officially declared bankrupt. Michelin, Citroën’s tyre supplier and one of its many concerned investors, did a deal with the main creditors, banks Paribas and Lazare, and gained control of Citroën in January 1935. André Citroën was very ill by that time; he died of stomach cancer six months later.
Citroën designed the Traction Avant as three cars. The first was a small body shell for the base 7 range and the performance-oriented “11 Légère”. The second was a larger and wider body for the family-minded customer (“11 Normale”). Though similar-looking, their body panels (except the front doors), width, grille and roof pressings were different. Both the small and large cars came in saloon and two-door coupé and roadster variants.
The third Traction was a long wheelbase (LWB) six-light body shell for 11 limousine and nine-seater familiale. Early LWB shells had symmetrical front and rear door openings that looked nice but undermined the body’s structural strength. Not a few LWB Tractions simply broke in half at the B-pillar. To provide extra rigidity, the rear doors were switched to those of the saloon, but the issue was never entirely resolved. Like the aborted 22, the 15-Six would only be available on the large and LWB bodies.
Turning Lemons Into Lemonade
Soon after Michelin took over, the V8 programme was simply cancelled – it had been launched way before it would be ready for production, yet again. Getting the 22 sorted would have diverted focus from the 4-cyl. cars, which also needed a lot of urgent attention but were showing promise.
Thanks to countless mechanical, structural and production fixes, by late 1936 Citroëns were solid and dependable cars again, but with far better handling and safety than virtually anything on the road. Michelin instilled its penny-pinching conservative values in the Traction, which lost some of its brightwork, made do with only one tail light and fewer paint options. Reintroducing the RWD range (with ‘reversed’ Traction engines) also helped the bottom line.
When the RWD range was pensioned off for good after 1937, the 11 commerciale utility wagon was launched to try to convert French small businesses and rural folk to the wonders of FWD.
Now that the Traction had been sorted out, Pierre Boulanger (“Michelin’s man” at the helm of Citroën) could turn his attention to making the front-drive subcompact TPV (Toute Petite Voiture, the 2 CV) and also revisit André Citroën’s original idea: a range-topping luxury model, but not a V8. Something that would work.
Six, please, we’re French
The cancellation of the 22 did leave a gap at the top, but the 3.8 litre V8 had proven heavy, thirsty and less than brilliant. So a straight-six was programmed instead. Because the last 6-cyl. Citroën (the RWD model) had been called “15 CV”, Citroën decided to keep the name, calling the new car “15-Six”. However, the car’s fiscal rating was 16 CV, as the Traction’s 6-cyl. was a bit bigger than its RWD ancestor’s unrelated engine.
The new 2.9 litre 6-cyl. was basically the 11’s 4-cyl. with a two extra cylinders, calling for a noticeably longer nose than the 11 B. Tooling costs were kept down by using front wings and headlights identical to the 11’s. The 15-Six was a heavier car, with velours seats and a bit more chrome. It could reach speeds of 80-plus mph, though at those speeds, it would do about 20 l/100km (12 mpg).
The first cars, all black saloons, were sold to selected clients and Citroën or Michelin executives in May-June 1938. The 15-Six was officially launched at the last Paris Auto Show before the war in October 1938 as a saloon; the LWB limousine and familiale versions were introduced in March 1939.
Tractions from this era used these attractive Michelin ‘Pilote’ wheels. The Six’s Pilotes were cream-coloured (the 11 B had red ones and the smaller cars’ were bright yellow). The 15-Six’s grille was then painted black and its headlights were fully chromed. This would change soon after the war. Also, the 15-Six sported louvres on its hood – this was adopted by the 11 in 1946.
Had the 1939 Paris Auto Show taken place, it is likely that Citroën would have introduced the 15-Six two-door roadster, along with the 2 CV. As such, only about three roadsters were made in late 1939 and perhaps a couple more in 1946-47. This one, the 1939 “Madame Michelin” 6-cyl. roadster, is the only one with a fully traceable history – so it could be the only genuine 15-Six roadster left.
The Queen Of The Road’s Loyal Opposition
The 15-Six was born at a time when there was a glut of big French cars. It sounds strange, but the ‘30s were another world. To better understand the Citroën 15-Six’s appeal, let’s see how it compared to domestic cars with similar horsepower and status.
Leaving out super-expensive blue-bloods like Delage, Delaunay-Belleville or Voisin, as well as those that were below 12 CV (Berliet, Licorne, Rosengart, etc.), 11 competitors remain in the 15-Six’s segment. Here they are, sorted in ascending order according to their 1939 list price.
The Citroën’s most dangerous rivals were the Matford V8s and the Renaults: modern-looking, well-appointed and well-built vehicles. But in terms of handling, technological advancement, safety, interior space, speed and value for money, Citroën was a clear winner. Most other marques could best the Citroën in terms of finish or luxury and could be more comfortable, but on the road the cheaper and roomier 15-Six would always be the car in front.
Of all the competitors, only Panhard also used an all-steel unibody construction – many were still ash-framed. Hydraulic brakes remained a minority, whereas independent front suspension was becoming the norm. The only aspect that let the 15-Six down was its lack of a fourth speed; the popular Cotal electromagnetic gearbox would never have been able to fit in front of the Citroën’s tightly-packed engine compartment.
Car production was drastically cut down by 1940 for obvious reasons. A handful of the Sixes were still being made when Germany invaded France, but from 1941, the 15-Six went on a five-year hiatus. Several privately-owned cars were commandeered by the Germans, and it is ascertained that a few made it all the way to the Eastern Front.
In 1946, the 15-Six went back into production, with 203 units made that year. The car was already eight years old, but its moment would finally come.
The first major modification to the 15-Six took place in 1947. The engine up to that point had been “turning left” (anti-clockwise), the opposite of the 4-cyl. Tractions. (No one seems to know for sure why the 6-cyl. was designed this way initially.) The engine’s rotation was switched to clockwise, necessitated by a new strengthened gearbox. This led to a new grille: the starting handle’s shaft had moved up, the old hole was hidden by a pair of chrome wings. The engine also received a revised head and several smaller modifications – the power output of 77 hp @ 3800 rpm remained the same, though the compression ratio went down slightly, presumably to better cope with the lower quality of post-war gasoline.
The first-generation 15-Six retroactively became the 15-Six “G” for “Gauche” (left); the new 15-Six was nicknamed the 15-Six “D” for “Droite” (right).
Competition had thinned out by now: Renault and Panhard had switched to small cars; many other automakers had pulled out or were moribund (Chenard-Walcker, Unic, Licorne, etc.) or aimed further upmarket (Talbot-Lago, Delahaye) to the Bugatti level, as Bugatti were no longer in business.
Only Ford, Salmson and Hotchkiss were still directly competing with the 15-Six. The new Ford Vedette would become the big Citroën’s only real competitor from 1948: it had a V8 (12 CV), it was comfortable, it had a real boot, it was more modern-looking and glitzier, and it was priced right. But the Vedette was slower, heavier, clumsier and thirstier that the 15-Six, and not as well built.
The 15-Six gradually put on more chrome with bigger hubcaps in 1950 and stouter straight bumpers in 1951. but the big change came in late 1952: the Traction range was given a bigger boot, new interiors, turn signals front and rear, windshield wipers at the bottom of the windscreen and other small changes. In 1954, the LWB models, which had been mothballed since the war, returned to the 11 and 15-Six ranges. Also, Tractions could now be ordered in blue or gray, though most still came out black.
In April 1954, the upcoming DS’s famous hydro-pneumatic suspension was debuted on the 15-Six’s egregiously rigid rear axle, becoming the “15-Six H”, though the normally-sprung 15-Six remained available through 1955.
The 15 H had the same engine but with a higher compression ratio, making it slightly more powerful (80hp @ 4000 rpm) and a bit quicker than the previous Six. To try and match the softer rear suspension, the 15 H had much longer torsion bars at the front, which stuck out on either side of the bottom of the grille.
This final iteration of the 15-Six was really a test-bed for the innovative suspension, though it did provide the fortunate few who could afford one, as well as a chauffeur, a level of comfort hitherto unknown in the back of a Traction. Production of all Citroën sixes stopped in 1956, as DS production ramped up.
The 15-Six In Numbers
Just over 50,000 Citroën 15-Six G, D and H were made from 1938 to 1956, out of a total production of 759.111 Traction Avants (1934-1957). These may seem like paltry numbers by today’s standards, but in fact the 15-Six sold in much larger quantities than all its competitors (except Ford) and effectively captured the market for executive cars in France after the war.
Production was still ramping up when the war came; less than 2500 cars had been sold by 1940. The 15-Six’s top-selling year was 1951 – twelve years after its first season, and five years before retirement.
The 15 H is usually considered to be a distinct model, though part of the 15-Six family. A little over 3000 were made in two years.
Six Specials And Foreign-Built Saloons
In 1955, French president René Coty, an older man with health problems, was recommended Citroën’s hydro-pneumatic suspension by his physician. He personally ordered a 15 H limousine (one of only two ever made, as the 15 H was only produced as a saloon), soon after having two new official state cars built on a stretched Citroën 15 H platform to replace both his predecessor’s Talbot-Lago convertible and Marshal Pétain’s 1942 Renault Suprastella town car.
The first 15 H-based state car was a limousine designed by Philippe Charbonneaux and bodied by Franay in 1955 – the coachbuilder’s final piece before closing shop.
The second presidential 15 H, a four-door convertible parade car, was made by Henri Chapron in 1956. Its peculiar beltline dip was designed by Carlo Delaisse so that the VIP likely sitting there might be better seen by the happy taxpayer in the street.
These were in service until about 1974, when these and several other state cars were (bizarrely) donated by president Pompidou to his doctor. By all accounts, these cars’ longer and substantially heavier ash-framed bodies were very tough on the 80 hp Citroën engine, so these were not usually driven on the open road, unlike the later SM phaetons.
Other interesting designs include the Swiss coachbuilt cars. The Traction was quite a hit outside France. Countries with no large “national automakers” to turn to such as Austria, Scandinavia, Spain, Portugal, the Netherlands or Turkey were very keen importers, as were the Swiss.
Switzerland also had several world-class master coachbuilders, such as Worblaufen, Beutler, Graber and many others. The great contribution of these coachbuilders was to provide a trickle of bona fide two-door versions of the Traction, which Citroën were no longer making after the war.
The French carrossiers we not as inspired as their Swiss colleagues by the 15-Six (or by Citroëns in general in those days).
This pre-war 15-Six limousine was heavily customized with long bulbous wings, a bigger trunk and a remodeled front end by Antem in 1948. The original car’s greenhouse was untouched – an illustration of the challenges many coachbuilders were facing with the spread of unibodies.
One singular innovation was Georges Regembeau’s handful of genuinely fast Sixes. The only visible differences were its wire wheels, fatter tyres and a added brightwork. The engine was reassembled and finely tuned, given a supercharger and fuel injection, as well as a six-speed box and special brakes. Power jumped to 195 hp and one was clocked on the Montlhéry racetrack at 210 kph (130 mph).
A few dozens of cars were transformed by specialists to have a canvas roof – the découvrable”, a fad that hit its peak in the ‘50s. This 15-Six has an AEAT roof, as well as an aftermarket Grégoire suspension, designed by engineer Jean-Albert Grégoire, a FWD pioneer in his own right. These Grégoire all-alloy IRS set-ups were a welcomed improvement over the Traction’s notoriously stiff ride.
The Traction Avant was sold in many countries, but it was only made in three. Citroën had an assembly plant in Forest, Belgium, which assembled CKD cars from 1926 to 1980. Belgian Tractions had locally-sourced wheels, grilles, turn signals and other small details, and were available in colours other than black.
In the Citroën factory in Slough, Buckinghamshire, colours were also available and the cars had nice leather interiors. Many British-sourced components were used for the car, including Smiths instruments for the lovely wood-clad dash, and oversized headlamps and electrics courtesy of Lucas “Prince of Darkness,” Ltd.
A good condition 15-Six can fetch €30,000-40,000. That’s ‘60s Cadillac money for the best ‘50s car the ‘30s ever gave us. It’s a bargain, it’s a steal. Speaking of which, this was probably the most successful getaway car of the ’40s and ‘50s. So successful that even the French police had to buy a few to keep up.
So that was the story of the Citroën 15-Six. It was beloved by everyone from bank CEOs to bank robbers. But most of all, it was the last French straight six ever made. They called it “la reine de la route” (Queen of the road), but human French royals were nowhere near as successful as this mechanical one.
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