Swings and roundabouts

More thoughts on swing axle suspensions and the benefits of a drop snout chassis

- MARK ORTIZ

Thank you for your interesting article on the Corvair, (RE V30N8) and the swing axle design that so attracted Nader’s ire. In it you listed several car manufacturers that used this cheap and simple suspension but omitted the car whose designers evolved the swing axle more successfully, and cheaply, than most.

Standard Triumph chose the swing axle for its ‘small-chassis’ series of models, the Herald, Spitfire, GT6 and Vitesse.

Motoring journalists knew as well as designers how to get such an axle to ‘jackup’ and did so (for their photographers) immediately, giving the cars a poor reputation. Triumph replied for the more powerful GT6 and Vitesse by adding a lower wishbone, but the design was heavy and expensive.

As you say, ‘what works best for a swing axle is stiff springing in ride…and soft springing in roll’, but you only gave Formula Vee as the example. Triumph came up with the ‘swing spring’ that did just that, by allowing the transverse spring to pivot in the centre, which reduced the roll resistance of later cars by 75 per cent! This most successful modification is, I believe, unique, and I feel Triumph’s ingenuity should have been recognised.

THE CONSULTANT

The ‘swing spring’ is one of many ways to skin this particular cat. The oldest I know of is Mercedes’ third coil spring.