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Chrysler Torsion Bar Car Suspensions, 1957-1992: Torsion-Aire, Torsion-Quiet

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Chrysler Torsion Bar Car Suspensions, 1957-1992: Torsion-Aire, Torsion-Quiet

When Chrysler started using torsion bars for their front suspensions, they were not new, but they were a first for a major American manufacturer, and possibly a first for low-price and medium-price cars.

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Packard had started using a complex four-wheel torsion bar setup in 1955 and 1956, and some expensive European cars used them.

Originally devised by Bob Batchelor, Chrysler's torsion bar suspensions were used across the entire lineup, from Plaza and Valiant to Imperial, for decades. Chrysler's implementation was unusual for its universal use and for combining front torsion bars with inexpensive rear leaf springs, instead of rear coil springs, in back.

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The rear leaf springs, with the axle mounted forward of center (asymmetrical design), kept the car level during sudden starts and stops, providing better heavy-load control than most existing rear-spring setups.

The torsion-bar front suspension debuted in 1957 across the corporation's models, and were used on all Chrysler Corporation cars until the front wheel drive cars arrived. The suspension was sold for some years under the trademark Torsion-Aire.

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There were many torsion-bar snapping problems in 1957, when the systems first launched, but by 1958, Chrysler had mostly resolved the problem.

In addition to the torsion bars, the company used an anti-sway bar (often just called "sway bar") to resist lean in turns, with various degrees of success depending on its thickness and the suspension tuning; generally, Chrysler Corp products had less body roll than equivalent GM or Ford cars. Diagonally mounted steel struts reinforced and positioned the front-wheel lower control arms.

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In back, widely spaced, off-center mounted rear leaf springs cut acceleration squat and brake dive; the pairing of cheap leaf springs with front torsion bars remained unusual through the system's life.

Jim Benjaminson wrote:

Called "Torsion-Aire Ride" (there was no air to the system at all, unlike GM's experiments with air suspensions), the suspension would garner Plymouth the title of best-handling car by Motor Trend magazine. Eventually, the entire Chrysler Corporation would receive Motor Trend's Car Of The Year Award based on "superior handling and roadability qualities."

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Torsion-Aire was more than just torsion bars; everything had been re-engineered, including the frame, wheels, tires, suspension, and steering linkage. The center of gravity had been lowered and the car sat on a wider stance.

Torsion-Aire used two chrome steel bars mounted parallel to the inner-front frame rails, the front portion of the bar mounted to the lower control arm with the opposite end anchored to the frame. Twisting motion of the bars, rather than compression of springs, provided the cars with soft but stable suspension. Even the rear springs had been redesigned to work in context with the torsion bars up front.
The front end of the torsion bar connected to the front wheel's lower control arm; the rear end of the torsion bar was anchored in the sub frame so the bar could not turn. When the front wheel rose over a bump, the lower control arm pivoted around the points where the torsion bar was mounted, twisting the bar. The chrome steel in the bar resisted the twist, holding the wheel on the road.

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The torsion bar front springs used a high proportion of chromium in their steel (though they have been known to snap). The anti-sway bar resisted lean in turns, with various degrees of success depending on its thickness and the suspension tuning. Shock absorbers limited suspension oscillations. Diagonally mounted steel struts reinforced and positioned the front-wheel lower control arms. Widely spaced, off-center mounted rear springs cut acceleration squat and also resisted brake dive.

John Hagen wrote:

Yes, the torsion bars could snap.
Oh boy, could they ever. At least the first two years production could, did. ... for the 1960 models, the adjustment point moved from the front of the bar to the rear. They only seemed to break at rest, not while on the road. The redesigned bars, including the replacements for the early cars, were very reliable - probably much more reliable than the coils used in the competition and way better than the airbags then in use on GM's high level cars; but in 1959, when the 1957s had started snapping, replacement parts were hard to find.

My father was a Dodge factory rep from 1952 to 1960. While passing through a dealership, he heard a gentleman not being all that gentle after being told it take about three weeks to get a replacement for his Desoto's broken right side torsion bar. As he was expressing his displeasure to the poor service writer, BANG went the left side.

The angled upper control arms resisted brake dive; and in newer versions of the torsion-bar suspension (used in the 1970s and later) the upper control arm had a front pivot higher than its rear pivot instead of at equal height so that weight would shift forward when the brakes were applied, counteracting the extra weight caused by braking and helping to keep the car level.

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Likewise, the rear leaf springs were off center, with the rear axle mounted on the thick forward sections of the springs instead of on the centers, so that the stiffer forward sections of the springs would support the body during acceleration and braking shifts. The long, flexible portions behind the axle benefited the ride.

One advantage of the system used by Mopar tuners through the years has been the ability to easily raise or lower the front end of the car by adjusting the torsion bars; with coil springs, the springs must be replaced. Likewise, if the car sagged with age, the torsion bar on that end could be replaced while a spring would be shimmed or replaced.

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In 1960, Dodge wrote: "Dodge torsion bars smooth out bumps with more positive control than coil springs. Rubber-cushioned diagonal struts help pull the front wheels over bumps."

Widely spaced upper and lower ball joints provided a wide base of support for the front wheels to improve stability and reduce undesirable wheel motion. Rubber-isolated nylon bearings allowed easier action than metal-to-metal, spring-loaded joints.

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Rubber bushings eliminated the need for lubrication in many spots, reduced friction, and absorbed road shocks. There were only eight lubrication points on the 1960 Chrysler, Dodge, and Plymouth cars' running gear; most other cars of the time had at least 16.

Rubber-cushioned struts ran diagonally from each lower control arm to the front crossmember of the underbody structure. They braced the front suspension against backward push, when the front wheels hit a bump.

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The system worked better than GM and Ford suspensions of the time, but eventually newer designs and the better materials to support them were developed. One insider said, "The engineer who came up with the system spent the rest of his career trying to get rid of it, because you could improve ride only at the expense of handling, and you could make it handle better only at the expense of the ride."

Torsion bars remained with Chrysler Corporation cars into the 1989 model year, their final performance.

Torsion-Quiet System

The Torsion-Quiet system launched in 1971 described rubber cushions which isolated the subframe and leaf springs, reducing vibration and noise the same way that rubber engine mounts do. The problem, though, is that as isolation was added, stiffness was necessarily and by definition reduced, so that cornering was degraded - though it was still better than Ford and GM.

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Mopar expert Rick Ehrenberg recommends retrofitting late-1970s cars with earlier suspension parts in many cases, to get rid of the extra isolation which seemed to have a greater impact on cornering than ride.

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Rick Ehrenberg also suggested a complete suspension check to make sure all components were in good shape, then adjusting the steering box to be as tight as possible; and aligning the front end. The specifications Rick provided for general street use were 1.5 degrees caster; -0.5 degrees camber; 0.1 inch total toe; and wheels and tires consisting of 15 x 7 inch wheels with 235R75 at minimum. A full description of how to set alignment without a shop was in the October 2009 Mopar Action.

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Following this, Rick recommend replacing the front sway bar with a stiffer one to take advantage of the better modern tires; in his project car, he went from the OEM 0.938 or 1 inch bar to a 1.25 inch bar, saying it made a tremendous impact. He then replaced the rear sway bar, rear springs, shocks, torsion bars (from Firm Feel, moving from 1.06 inches to 1.18 inches), and steering box (Firm Feel Stage 1).

Second generation torsion-bar suspension: 1978-1989

Chrysler turned to transverse mounted torsion bars for the 1976 Dodge Aspen and Plymouth Volare, because there wasn't enough room for them with new emissions controls.

Lanny Knutson wrote, "engineers devised a transverse torsion bar system incorporating L-shaped bars. The shorter arm of the L acted as a lever to the lower suspension arm. ... All components were mounted in a self-contained bolt-on unit that would find its way into street rods in years to follow."

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The system was praised, at the time, for its combination of ride and handling, and the Volare did seem like a jump up from the aged Valiant. In later years, there would be some problems in police use, mostly because hitting curbs or other vehicles tended to cause the front suspension to lose alignment; and in some years, the K-frames were not well made. The transverse torsion bar front suspensions died with the last of that series of cars, in 1989.

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When Chrysler went to front wheel drive, it also went to the MacPherson struts which were, by then, a de facto standard on front wheel drive cars. Still, torsion bars continued in two unexpected places.

Bob Sheaves added:
"The same engineer (Bob Batchelor) responsible for the M-body design (transverse bars) corrected the problems on the [Eagle] Premier, in that the bars were "folded" together into a single, more compact design that was more rigid in bending and smoother riding, due to lower rate and greater travel."

The Eagle Premier had the usual front-drive MacPherson strut front suspension, but instead of a solid beam rear axle in back, it used an independent torsion bar rear suspension.

The four wheel drive Dodge Dakota also used torsion bars into the 1990s, and the cornering was excellent.

Leaf spring performance

"Dana44" wrote:

One trick with the leaf springs is to angle them. If the front eyelet attachments are two inches (one inch each) closer together in the front, and the rear eyelet remains stock, the torional twist of the offset which improves handling. For example, if the front eyelets are 58 inches between the two front eyelets, the rear are 60 inches between the two eyelets, not only do the springs now flex up and down, but they also twist a little bit when they go up and down, which improves cornering.

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Coils take up less room, allow one to lower the car (to drop the center of gravity), and allow moving the rear wheels farther to the rear. The MacPherson strut design puts the coil spring and shock together to eliminate parts, but to get them to handle as well as leaf springs, the ride gets rough, so it is a tradeoff.
Tannon Weber pointed out:

Unsprung weight is a disadvantage, and with the leaf springs, the axle is unsprung. You have to go true independent suspensions to reduce unsprung weight.

There is an advantage in a driveline where one doesn't have to work with pinion angles and other driveshaft geometry because the differential is attached at the body. But doing maintenance is a lot harder too, as changing out shocks is hard.

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