Corvair emblem Corsa

Corvair Handling and Stability

The intended purpose of a vehicle (how that vehicle will be used by its owners) plays a major role in the design of a vehicle's suspension system. The original Corvair wasn't designed to burn up the racetrack. It was intended to compete with the small, inexpensive European imports such as the Volkswagen. The imports were light and extremely fuel efficient, and their popularity was astounding. The Corvair, if it were to compete effectively, would be an economy car. However, its unique design would be embraced more by driving enthusiasts than by the economy buyer, and this resulted in some changes in Chevrolet's marketing strategy. Within the first two years of production, the car would be transformed from an "economy" to a "sporty" compact.

The big three American manufacturers had all released new compact cars for the 1960 model year. Ford and Chrysler chose simply to build a smaller version of their full size cars. They took a conventional approach to the compact, and used a front engine/rear drive configuration, with a conventional solid or "live" axle at the rear. Chevy opted for a rear engine configuration similar to the Volkswagen, which dictated the use of an independent rear suspension. A conventional solid axle was out of the question, as the differential carrier could not be suspended with the wheels. The differential carrier, transmission and engine were combined into an assembly called a "Uni-pack," from which two separate axles extended to the rear wheels from universal joints at the differential carrier. This is known as a swing axle configuration, and at the time was common to Mercedes Benz, Porsche and Volkswagen.

In a conventional solid axle setup, the rear wheels remain perpendicular to the ground, no matter how heavily the vehicle is loaded, and in all handling situations. With swing axles, the rear wheels move in arcs around their attachment points at the differential carrier. This means that when a swing axle vehicle is heavily loaded, the wheels arc up slightly into a negative camber stance where the top of the wheel and tire leans into the wheel well. Conversely, when the wheels are unloaded, such as is the case when on a hoist for servicing, they arc into a positive camber orientation shown in the top right part of the illustration below.

When the Corvair was introduced, the arcing action of the rear suspension was viewed by many North Americans as "looking funny." Wheels, they thought, were supposed to go straight up and down! While it might be okay for a Volkswagen's wheels to go into a V on a gas station hoist, a Chevy's wheels were, in the minds of consumers, supposed to be straight. The "odd" and changing attitude of the Corvair's rear wheels might have contributed to the controversy that developed regarding the Corvair's suspension.

Early Model Suspension

The drawing at right illustrates the difference between the swing axle used on 1960-63 Corvairs and same setup with a camber compensating, transverse-mounted leaf spring as used on the 1964 Corvair.

The drawing shows the rear suspension under roll (cornering) conditions. Lateral loading of the outside rear wheel causes what has come to be known as "tuck under" in the 1960-63 design. This condition, as the NHTSA determined, does not cause instability, but even today, it "looks funny." The addition of the camber compensator was a positive development, and one that improved the handling or the 1964 Corvair, considered by many (but not all Corvair fans) to be the best of the early models.

Early model Corvair rear suspension

Comparison View - Early vs. Late Model

In time for the launch of the second generation Corvair ('65-69), Chevrolet drew on the expertise of Corvette engineer Zora Duntov, who helped cook up a variant of the Corvette independent rear suspension (IRS) for the Corvair. Chevrolet had moved from a solid axle to an IRS in the second generation Corvette, the 1963 Stringray. The Corvette design used half-shafts with universal joints at both the differential carrier and the wheels. The Corvair received the same treatment, with a couple of significant differences; the Corvette used a single, transverse-mounted leaf spring, while the Corvair continued to use a coil spring at each wheel. The Corvair also got a lower link or strut as can be seen in the illustration at right.

With the late model setup, the Corvair rear wheels remain in a relatively perpendicular attitude under most operating conditions. The suspension design is intended to be set up with slight negative camber. When put up on a hoist, the late model's wheels settle to a slightly positive camber. This design looked better, but more importantly, it resulted in further improved handling for the Corvair, a fact that even Ralph Nader acknowledged in his book. 

Early and late model Corvair rear suspension

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