Remember when Zora sued Car and Driver?

[Duke W.]

Car and Driver's 50th Anniversary Edition (July 2005) has an excellent (and humorous) anthology of their half-century of antics and mention was made (page 196) of Zora suing (or perhaps threatening to sue) Car and Driver over their unkind remarks about the his patented three-link rear suspension circa 1979, which was after he retired from GM.

Though I am hesistant to criticize The Master, his design did have some deficiencies - excess toe and camber change and poor squat control - though it was very innovative for its time, and its cost was low enough to get past the bean counters.

C4 went a long way with a five link, though still using the halfshaft as one link somewhat compromised geometry. The SLA (short-long arm) suspension in C5 and C5 is a no-compromise five link (each A-arm is effectively two links and the front tie rod and rear toe link are the fifth links), and no one has ever invented anything better and probably never will.

An unconstrained body in space (think of a spacecraft) has six degrees of freedom - translation along and rotation about the three orthagonal axes, so if we want to constrain motion to just one degree of freedom (purely up and down in the same plane) five links are implied!

Does anyone remember if Zora actual did file a suit against CAr and Driver and how it was resolved?

Duke

[mike cobine]

Re: Remember when Zora sued Car and Driver?

While the C2 IRS had several problems, for its time, it was great. The halfshaft as a member solved a problem that other IRS designs had that would have suffered in Corvette.

Most that went with a link above and below the halfshaft could not keep geometry perfect, due to bushing deflection, and so the stub axle had to move or bind the suspension. This was solved in some cases with the rubber donuts or with sliding splined stub shafts. At the time, neither would have handled the anticipated power and torque Corvette would have. And not at the cost needed for GM to allow the IRS.

Can you imagine a 427 with a Formula Ford style rubber donut?

The parts I always thought were poor design, and didn't really cost or save GM anything, was mounting the front trailing arm bolts where you couldn't get to them. Did the body have to wrap around them? Did the brake junction have to go right on top of where the bolt head was? And in '68, did the braces have to cover what space was there?

The rear cover mounts in a way that removing the cover is nearly impossible in the car.

[Duke W.]

Re: Remember when Zora sued Car and Driver?

The three link C2/3 suspension using the axle shaft with double U-joints was an improvement over the closely related swing axle architecture, but using the axle shaft as an upper lateral link forces you to accept a rather high roll center, which causes a lot of camber and track change and can also cause "jacking", but not as bad as a swing axle.

And the single member trailing arm doesn't allow good anti-squat characteristics.

C4 fixed the problem at least halfway by implementing two trailing links for better squat control, but still had a high roll center because the axle shaft still doubled as an upper lateral link.

C5 and C5 eliminated the high roll center issue by removing the axle shaft as a suspension member and implementing upper and lower control arms. This lowers the roll center, which reduces camber, track, and toe change, while allowing good anti-squat characteristics.

Millikan's "Race Car Vehicle Dynamics" is an excellent text on suspension design if anyone wishes to pursue the subject in more depth.

So, back to the original question. Anyone remember the resolution/outcome of Zora's lawsuit against Car and Driver?

Duke

[Donald T.]

Re: Remember when Zora sued Car and Driver?

Orthagonal? Isn't that when you get your teeth straightened? Anti-squat? Isn't that what immodium does?

Duke, you are waaaaaaay over my head!

[Duke W.]

Re: Remember when Zora sued Car and Driver?

Sorry - typo - should be orthogonal - sometimes called "x-y-z axes".

Duke