I worked at Chrysler Central Engineering from 1959 to 1961 when the
"Torsion-Aire" suspension was just two years on the market. The stated
reasons for going to a torsion bar spring were two-fold as I recall:
1. Packaging - lower front profile for the 1957 cars. It was
easier to package a long bar parallel to the frame than try to tuck a coil
spring between the upper and lower control arms.
2. Adjustable suspension height to avoid matching front coil springs at
the plant.
Along with the torsion bar spring a new suspension geometry was
introduced to improve handling and control front end "dive" when
braking. This had nothing to do with the choice of spring configuration
but it may have been easier to design in the desired geometry without a coil
spring to restrict packaging.
As I recall the torsion bar spring rate was higher than the coil
spring. This stiffer ride improved handling. To compensate
for the stiffer ride a new 14" tire was introduced. This provided the
"Aire" component of the "Torsion-Aire" ride. (more than likely
invented in the marketing department). The new suspension was a good one
and probably the most advanced of its time. It represented probably the
best ride/handling compromise of its time but this was due mostly to the
geometry and tire selection and probably had little to do with the spring
configuration.
I'm not sure but as I recall the suspension design looked a lot like the
Citrone at the time. As for the torsion bars influence on ride and
handling it really didn't. The conventional wisdom at Chrysler
was: whether you take a piece of spring steel and stretch it into a rod
or coil it into a spring it is still a spring and like all springs must
obey Hookes law.
This is my 2 cents worth on the Torsion-Air ride of the 50's at
Chrysler. My memory of events nearly 50 years ago is not perfect but
this is my recollection.
When I worked in Chassis research a rear torsion bar car was prototyped
(a 1959 Plylmouth) and development work continued for 2 to three years but it
never made it to production. The comments were: "the leaf spring, with
its multi functions, is just darn hard to replace.
Rolland
Westra