In 1955, Packard introduced a novel and advanced suspension system called Torsion-Level Ride. Here’s the lowdown on this little-understood system, including an excellent little Packard film that shows exactly how it works.
By 1955, the Packard Motor Car Co. was doomed. Despite a hopelessly optimistic buyout-merger with Studebaker in October of 1954, the company was circling the drain. But that didn’t stop the venerable Motor City automaker from introducing a whole series of new engineering features, including a high-quality V8 engine, an advanced and improved Ultramatic automatic transmission, and an innovative suspension system called Torsion-Level Ride. Due to the company’s rapidly failing health, Torsion-Level was offered for only two years, 1955 and 1956, so the system isn’t very well known or understood today. That’s a shame, because it’s a fascinating and clever setup.
Created by Hudson engineer William D. Allison, the Torsion-Level concept lacked a suitable application there, so it was offered to Packard in 1947, where it was developed under the direction of Advanced Engineering boss Forest R. McFarland. In 1955, the system was made standard on all senior Packards and some Clipper models, optional on the rest of the line.
The name Torsion-Level might be a little misleading to modern ears. Unlike current self-leveling suspensions, the Packard system did not adjust vehicle ride height or attitude in real time, but only to correct for passenger and luggage load via a seven-second delay. This was accomplished with a large electric motor that adjusted the preload on a pair of torsion-bar compensator springs to level the chassis in relation to the road.
No, the real innovation of Torsion-Level Ride was in coupling the front and rear suspension with a pair of chassis-length torsion bars that tied the front and rear wheels together (see illustrations). Coupled front/rear suspension is not a unique feature but it is a rare one, employed on the original Citroen 2CV and a few other cars. What it allowed Packard to do was to effectively manage pitch, a serious issue on large American cars of the ’50s. Their marshmallow-soft springs provided a cushy ride, but with excessive roll, porpoising, and a scary tendency to nose-dive under braking and motorboat under acceleration.
By coupling the front and rear wheel motions, Torsion-Level Ride significantly reduced the pitch frequency of the chassis (as well as its skew rate). This permitted Packard to use soft spring rates but without the poor body control effects, enabling greater stability and comfort. If you ever get the chance to travel in a ’55 or ’56 Packard, you will find the ride really is exceptional—as close to the proverbial cloud-like ride as you will encounter in a ’50s American car.
Would Torsion-Level catch on today? Probably not. We have much better roads these days, including an Interstate highway system, and some very advanced suspensions in their own right. But in this clever and simple little Packard clip, we can see exactly how the Torsion-Level setup works. Video below.
Awesome story, McG. All new to me. I thought Torsion Level was merely torsion bar. Excuse me for being wet behind the ears but unfortunately my engineering degree is in this century. What is a skew rate? Is that basically the same as warp?
Except for the packaging problems this could really work today. Obviously, active can do the same thing.
Exactly correct, skew and warp are the same thing. Sorry for causing the confusion. The front and rear wheel loads are fed through the springs into each other instead of into the chassis where they twist and bend the structure. So here the suspension calibrations — springs, dampers, ARBs, etc — can be tuned as if for a far more torsionally rigid chassis. Very efficient. There’s a good section on the math in Milliken’s Chassis Design.
I enjoyed having that final “aha” moment with the long torsion bar which did not have to be anchored to the frame. I told my Dad, who was a teenager in the 50’s. He told me a story. When he was at one of his family’s gas stations in Kingsport, TN, the Packard dealer was a short distance away downtown. Somebody told him “you won’t believe this” but go push down on the back of the new Packards and wait. They’ll crank you back up. So he did that, sitting on the back of a new Packard in the showroom, and after 7 seconds, getting “leveled”. That was amazing.