Moulton and the Mini

For the duration of the 1950s and 60s, Alex Moulton and Alec Issigonis were great friends and daring collaborators. Together with John Morris (of SU carburettors), they were known in motoring circles as ‘the Three Musketeers’. Issigonis had already established his reputation with the Morris Minor, while Moulton was busy developing a new suspension system using rubber elements loaded in torsion and shear, specifically for automotive applications.

Issigonis was initially unimpressed, although he had previously used rubber suspension on this ‘lightweight special’ hill-climb car. After Issigonis moved to Alvis, Alex Moulton persuaded Jack Daniels to fit a prototype rubber suspension system to a Minor. A thousand miles of MIRA pavé convinced Issigonis that rubber was an excellent suspension medium for passenger cars. 

Moulton joined the Issigonis team at Alvis.

The suspension system proposed for the Alvis TA350 comprised a pair of Moulton rubber cones (originally developed as engine mounts for the Admiralty) placed ‘nose-to-nose’ in strut form at each wheel. From this came the inspiration that the cones could be used as fluid displacers as well as primary springs; the cones were arranged ‘back-to-back’ to form a fluid chamber and the front and rear units were inter-connected hydraulically. 

This inter-connection greatly reduced the pitch motion and increased the roll stiffness, of the car.  Moulton later commented,

“I shall never forget the revelation at Coventry, with Alec driving, of experiencing the ‘big car’ ride due to the lowered pitch frequency. The reality of the benefit of fluid interconnection was thus revealed and the seed was sown, not that we realised it then, for a radical new suspension to be made in vast numbers.”

The Alvis project never came to fruition, and as it was being wound up Issigonis was recruited back into the BMC fold. Suitably impressed by his work at Alvis, Issigonis persuaded BMC to sign up Moulton to develop suspension systems for their new range of cars.  The first of these was the Mini in 1959. 

For this, Moulton’s inter-connected system was not yet available (Moulton said of the protracted development phase,

“We had no analogy to fall back on; indeed the devices were more akin to biological organs than engineering mechanisms”

So the Cone spring was used – now in a double-wishbone levered installation – and its rising-rate characteristics coped admirably with the very large changes in load and weight distribution on such a light car. It was also so effective in sticking the Mini to the tarmac that even base models were competitive with much more powerful cars covering the road, persuading BMC to build a performance version – the Mini Cooper.

Moulton and Issigonis were kept busy by BMC, and 1962 saw the launch of the Morris 1100, the first car featuring Moulton’s Hydrolastic inter-connected suspension. Hydrolastic found its way onto the Mini in 1964, and all the famous rally successes were on this ‘wet’ suspension. Cost-cutting measures by new owners British Leyland saw the Mini revert to the ‘dry’ Cone springs in 1969, much to the chagrin of Moulton. 

Despite his protests that the greater weight of a 1970 car demanded a longer Cone spring, Leyland used the original size and compromised the ride of the car – after all, the Mini would soon be replaced.

Moulton converted his 1966 Mini Cooper S into a Mini limousine – a seat for his driver and a seat and a desk in the back, a smooth ride provided by Moulton Hydragas suspension – and would take delight in demonstrating to executives and engineers from car companies around the world how well a small car could ride. 

Alex Moulton’s ‘Long Cone’ spring finally became available to Mini owners in 1999, after production of Issigonis’ iconic car had ceased. The last car with Moulton suspension – an MGF with Hydragas – rolled off the line at Longbridge in 2002; 43 years and over 12 million cars after the first. 

Alex Moulton kept his Mini Cooper S – always his favourite – until he died in 2012.