to correct rancid pickle
, the early models of the corvair had what is known as a swing axle
rear suspension, which is the same as used in the original, and very succesful Volkswagen Beetle
A swing axle is a type of suspension where both halfshafts have a u-joint just outside the differential. When a swing axle car hits a bump, the load pushes in on the differential, tending to lift it. This is referred to as a jacking effect, and in effect raises the car's center of gravity. This makes the car less stable in turns, and more prone to flips.
The reason Chevrolet engineers chose a swing axle design, is that it is a cheap way of isolating the engine and transaxle from bumps. Without the u-jointed halfshafts, the engines would have moved along with the bumps, greatly increasing unsprung weight and harming reliability. The rear end would have bounced around. Dr. Ferdinand Porsche made the same decision in designing the Beetle and early Porsches, for the same reasons. However, the six-cylinder Corvair is a much more powerful, and heavy, car than the Beetle. The supercharged Corvair Spyder and Yenko Stinger models were very fast indeed. A few are still raced today.
Later models of the Corvair replaced the swing axle design with a fully independent suspension. This eliminated the jacking effect, and allowed for much better camber control, ride and reduced body roll. Ralph Nader actually noted this in his book Unsafe at Any Speed . His criticisms were confined to the early Corvair models, but the media impression was that they applied to all the cars. The later models are actually quite refined for the day.