The Sting Ray: A Technical Analysis

For the enthusiast, it is a good thing to be able to say that your car is based on a racing car (or that it has been successfully raced), so right from the beginning the ’63 Sting Ray was off to a good start. It was also far and away the most sophisticated production chassis to be made in the U.S., incorporating, as it did, independent rear suspension (IRS). The C1, by contrast, had a solid or, as we say in the UK, live axle. Such a rear suspension arrangement has the virtue of being simple, cheap to make and straightforward to maintain. It also has the inherent advantage of ensuring that the wheels are perpendicular to the axle line. As with much to do with car suspension, carefully thought out geometry and accurate location of components is essential if one wants to get the best out of it. Bristol Cars were, for instance, acknowledged to be extremely good at this (and just about everything else too) and their cars had extremely high levels of roadholding and a good ride despite having a live axle. 

One of the main drawbacks of the live axle, however, is that the whole thing constitutes “unsprung weight.” It is easier (although not easy) to get a car to ride well if the amount of unsprung weight is low. This includes wheels and tires, and is one of the main reasons for the adoption of wire, and then alloy, wheels (as well as better brake cooling, if designed well)—they are normally lighter than pressed steel, etc. You might not be very worried about a soft ride in your sports car, but you might be if the car is thrown off line by bad surfaces. If all roads were like race tracks, it would not be so much of an issue! Worse, of course, is that one wheel affects the other, as they are joined by the axle. Not only does this compromise potential roadholding, it also means that, when accelerating hard, particularly from a standstill, the torque of the engine tries to twist the axle around the centerline of the differential. This has the effect of making one wheel dig in and give good traction while the other is relieved of load and spins. The result, if you want to make rapid progress, is unseemly and unsatisfactory. It is possible to cure this by effectively tying the axle to the car, providing little, if any, suspension travel. This is how many pure drag cars are built and, while it works well with the extremes of power involved, it is hardly an ideal way of overcoming this shortcoming of the live axle in street use.