Our Cars : Alex Moulton was right…

Alexander Boucke

Hydrolastic, Hydragas or Hydropneumatic? The choice is yours....
Hydrolastic, Hydragas or Hydropneumatic? The choice is yours…

One can, of course, drive a car that has steel springs and hydraulic dampers on all four wheels – the wheels do bob up and down when driving down the road and manage to stick to the black stuff reasonably well. Over the past 40 years there has been a marked evolution of these suspension systems – up to the point that they are not really simple anymore. However, I still have the distinct belief that all kinds of hydraulically actuated and – more importantly – interconnected suspensions deliver.

Agreed, Moulton’s first effort, the ADO16, was outclassed when the modern hatches of the 1970s – namely the Alfa Romeo Alfasud and VW Golf, not to mention the Citroën GS, came along. But then, Hydrolastic was developed into Hydragas – integrating the major achievements of the 3litre towards more effective damping into a seriously refined setup. Even the much-disliked Allegro (count me in) offers a very decent ride quality from the start, despite Moulton not being happy with the under-developed damping that was installed in the first series. The 3litre and ‘wedge’-Princess can still hold their heads high with regards to ride comfort combined with a sure-footed drive on twisty, bad roads. In a strange way – when trying to ignore the slight floating sensation – they do feel way more modern than they should really do as 40-50 year old classics.

How about Citroën, though – one of Moulton’s big inspirations? Some have claimed that he sort of copied the French Hydropneumatic suspension and created a cheaper to build version of it. That is, of course, rather inaccurate, as he created a very original design by taking some of the best ideas from 2CV (the interconnection) and DS (the hydraulic actuation) and combined them with his own ideas. He did not dismiss Citroën’s efforts though and – to a point – Citroën impoved its own design where it was lacking compared to the British system.

Enter the Citroën XM: the classic Hydropneumatic suspension was always intended to give the best possible ride comfort, combined with safety and stability under all conditions. Creating a car with inspiring handling characteristics was not a key objective – at least not for the cars that actually went on sale. Already in the 1960s Citroën worked on active anti-roll suspension systems, knowing the weaknesses of the DS all too well. With the XM, a simpler, yet very effective system was introduced: Hydractive. This added the things that made Hydrolastic cars so entertaining to drive – when rushed, the suspension firms up, while still maintaining the virtues of original Hydropneumatic. Reacting to electronic sensors, Hydractive switches between soft and firm damper and spring settings very quickly and seamlessly.

French countryside - the best way to explore a big Citroën
French countryside – the best way to explore a big Citroën

After reading up all sorts of technical information on Hydropneumatic, curiosity got the better of me – and a late XM estate was added to the fleet. Two years and some 20,000 miles on and I am hooked. This is my every-day 3litre! Apart from being driven at the other end, the XM reminds me of the 3litre every day I drive it. As with the old car, it is most relaxing to drive for any kind of distance – and it does not all fall apart when really pressing on on a bad, bendy British B-road.

No wood, lots of leather - still a great place to be.
No wood, lots of leather – still a great place to be

It is all there, more refined, quieter, faster and more economical, as you’d expect with nearly three decades of development between the two cars. For sure, listening to the baritone of the 3-litre V6 engine in the XM on the open road, it is just missing the view of acres of polished walnut that really keeps me from feeling like I’m driving the old ADO61…

With just 388 estates made with the belt-driven 24-valve engine, I feel really lucky to claim one to be mine.

I was, of course, aware that, for more than a decade, one of the late Dr. Alex Moulton’s favourite cars was a Citroën XM – a saloon, but fitted with the same smooth 24-valve V6 engine as my estate.

Guess what? I think he was right after all!

More similarities in charcter than outwardly visible.
More similarities in charcter than outwardly visible
Alexander Boucke


  1. The XM is a car I know well, having owned three of them; they were the best estate cars that I ever owned and miss them still – even though I parted with my last one 14 years ago 🙁

    One thing I dismissed when it first came out was the air suspension on the Land Rover Discovery but, now that I have a Disco 4, it’s something that reminds me of the old Citroen every day. From the selectable ride height, to the self levelling and the decent (but not quite Citroen) ride, the LR is another big improvement on coil springs. I wonder why we all tend to ignore it when discussing these suspension systems?

    • Yes, air springs are very good, usually much more sensitive compared to the steel springs replaced. Due to lower amounts of inertia they tend to be better on correcting sharp irregularities compared to the integrated systems from Moulton and Citroën. In my opinion they lack on two areas in comparison : they are by far not as space efficient, as extra dampers will always be needed. And they do not give the particular feel that I have only ever encountered in the 3 systems mentioned in my post.

  2. The XM is a car I know well, having owned three of them; they were the best estate cars that I ever owned and miss them still – even though I parted with my last one 14 years ago 🙁

    One thing I dismissed when it first came out was the air suspension on the Land Rover Discovery but, now that I have a Disco 4, whilst clearly not quite as good, it’s still something that reminds me of my old Citroens every day. From the selectable ride height, to the self levelling and the decent (but not quite Citroen) ride and the surprising lack of roll, the LR is another big improvement on coil springs. I wonder why we all tend to ignore it when discussing these suspension systems?

  3. While it’s fashionable to knock the Austin Ambassador( well anything with an Austin Morris badge if your name is Clarkson), Hydragas gave this car a vastly smoother ride than its rivals from Ford and Vauxhall. On ride comfort and massive interior space alone, the Ambassador was way ahead of the opposition and you could tolerate the leisurely performance as the ride was so relaxing on a long drive. It’s clear if you wanted a large car that rode like nothing else in those days, it was either an Austin Ambassador or a Citroen CX.
    Now when is an article due on perhaps the most interesting French car ever made?

  4. The most interesting French car ever made? Where do you start?

    Citroen 2CV, FWD, monocoque, inboard brakes, interlinked front to rear suspension.
    Citroen Traction Avant.
    Citroen DS
    Renault 5
    Renault 16

    Dacia Sandero, £5995 lowest price “real car” you can buy

    • Of course the SM makes most of the powerful hydraulics, Diravi-steering, hydraulic leveling and turning of head lights etc – it is an engineering masterpiece. But when looking at the amount of unorthodox, but particularly effective engineering solutions, the simple looking 2CV has to be mentioned at the same level. The 2CV is very different to the cheap British opposition of the time, which were mostly primitive.

  5. @ Hybrid, I think these come close, but the Citroen CX stands out for its futuristic styling, Star Trek like dashboard, and fantastic ride and handling. Like the Rover SD1, which top models were pitched against, it had a few early quality issues, but these were sorted out and the CX became a most satisfying car to own and drive.

  6. Hybrid

    Super list of five most interesting French cars. May I suggest the following five to make a top ten:

    Panhard 24
    Citroen GS
    Citroen SM
    Citroen CX
    Simca 1200S Coupe.

    Yes, there have been excellent Peugeots (205, 406, 504) and ground breaking Renaults MPVs but not “interesting enough”

  7. I cannot agree that the Peugeot 504 was “not interesting enough”. It may have been front engined and rear wheel drive, and thus conventional in layout, but the execution was far from conventional. It had the hemispherical combustion chambers with cross pushrod actuation ; a slant four engine giving a low bonnet line ; the first French car with fuel injection ; and perhaps most ingenious of all a solid driveline with a torque tube to the final drive unit, which made it extraordinarily refined . I had one ( 504TI) as a family car for about 5 years from 1976 and it was a lovely car with an exceptionally good ride

    • The Peugeot 504 had a twin from Nissan, I cannot recall the model or name but the Nissan was a very close copy of the 504 sharing the same body shape, nose-down, rear-up long travel suspension, I think the Nissan had the three-row seating, I recall the Nissan serving as Paris taxis while working abroad in in 1982, I do not recall any mention of these vehicles anywhere else. Expressing interest in the Nissan to one taxi driver, he had owned more than one and they would run for 700,000 km without much bother, (typical of Nissan of the era then).

      Does anyone recognize the Nissan model as above and can post images or model designation?

  8. Looking at Alexander’s Austin 3 Litre, if it had better front end styling, it would be a very good looking car, as everything else makes it look upmarket. Also if the car had more performance, a better equipment level and was marketed better, it could have become an interesting alternative to a Rover.

  9. I forgot to mention the Citroen BX of the 1980s. possibly the last true Citroen which was aimed at a mass market, affordable to the everyday driver / owner, practical with the classic Citroen interlinked suspension and ride quality, reliable in diesel form to appeal to the minicab trade and the stratospeheric mileages and abuse such cars attain, one of my friends replaced his top of the range Range Rover Vogue with a BX ( and he knew a lot about cars with the cash to afford anything that took his fancy )

    • Xantia, which was something of an evolution of the BX, solidly built and felt less lightweight than the BX, affordable, practical, early models had the same XUDT diesel engines. Yes it looked less sci-fi than the BX, some argue it looked like a Daewoo Espero, the rear bootlid looked like it came from an E36 3 series. It never looked out of place in the company car park.

  10. I miss my Xantia, it absorded bumps like nothing else I have driven. It was the perfect car for pot holed Britain, you didn’t notice they were there. With the added bonus of height adjustable suspension for getting through floods.

    Alas rust got it, and now I am stuck with the rest of you with borring springs.

  11. Good to see the Xantia coming up in the discussion. My two were great, but what came after was dire (I ended up with two R75s so it wasn’t all bad!).

    The Xantia managed to be both proper Citroen and able to hold its own against boring opposition. It lost some of the quirks but that was no bad thing

    Other great French car? Renault 4. I went to my wedding in a banana yellow one. Fabulous thing!

  12. Citroen BX vs Peugeot 504:

    From memory the 504 had a reputation for durability, and with its classic long travel suspension was popular in Africa, the 504 being able to take the punishment from African roads which would destroy most other cars.

    Does anyone recall the “Car For Africa” company, several prototypes of cars designed for local production, such as wooden bodies, there was a TV documentary with proving models cars being driven across Africa, I think the project ran out of funds even though the prototypes were proving to be successful in the field trials

  13. I think you will find the Wolseley ADO61 prototype with the Rover V8 engine ticked all the boxes.

    As for interesting French car – Matra 530LX.
    Mid engined 2+2 with a real boot and a hoot to drive. Not really a road burner with a Ford V4 engine but the absorbent ride and sheer practicality of the thing won me over. Where are they now?

  14. Alex Moulton also showed me his Bentley Saloon when I visited him. I believe it was a Turbo-R, certainly it was a ‘SZ’ series. He’d bought it as a birthday present to himself and had the suspension settings made bespoke, but with Factory Approval. He did stress that only changes to the suspension would be made provided the chassis team in Pyms Lane approved, which they did. I often wondered what the changes were and where the car is now.

  15. I think the difference between a RR and a Bentley reflects the important matter of the driver of the car and the owner of the car
    The RR owner occupying the rear seats, having paid a great deal of money for the car, experiences the better ride, for the Bentley, the occupant of the driving seat experiences the better ride.

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