The fact that the original suspension design under early Ford vehicles through the late '40s was based on horse and buggy technology should be all one needs to hear to convince them that it's worth a second look when it comes to setting up their hot rod's suspension. Yet as antiquated a design as it is, for most intents and purposes, the transverse spring and wishbone design performs quite well if the end result is one of more aesthetics than performance. Those who yearn for a better performing suspension design don't have many choices if the straight axle and radius rod setup is to be retained. The aesthetic drawback of coilover shocks or an IFS setup compared to the performance upgrade accomplished by such is oftentimes not worth the trade. Bottom line: If the car is to be built in a traditional manner, there are few options when it comes to suspension designs that won't deviate from the hot rods of yore.
Yet there is one setup that cannot only incorporate the original transverse axle/radius rod design, but can maintain the aesthetics of the early period hot rods and perform better than that old transverse spring torsion bar suspension. It's been a staple in various racing circuits for decades and has been used in production vehicles going back to the '30s. The ease of adjustability and simplicity of design makes it ideal for vehicles where space is limited and suspension adjustments necessary and the ability to change out many of the variables to dial in the performance and handling characteristics of the suspension system has proven itself to be a favorite among race teams and car builders alike.
One such shop that has had plenty of experience in setting up traditional torsion bar-sprung hot rod chassis' in the past is Moal Coachbuilders. From Paul and Eric Hansen's AMBR-winning "Sedeuced" to George Poteet's "Roadchamp" five-window, the crew at Moal's has refined the art of torsion bar-sprung chassis with the help of the torsion bar guru himself, Gary Schroeder of Schroeder Racing Products. Together, they've designed a chassis that combines all the components we typically refer to as traditional for the '32 Ford (Deuce 'rails, straight axle, radius rods) with the benefits of a torsion bar setup. Available as a roller, their '32 T-Bar chassis features improved ride, handling, and tuneability commonly referred with a torsion bar chassis. Featuring fully boxed 'rails with the stock reveal, the chassis is pinched 1 1/2 inches up front with a C-notch at both ends for improved suspension clearance. Transverse-mounted torsion bars at both ends mate to custom Billet 4130 chromoly arms that are fully adjustable via stop bolts. A dropped I-beam axle mates to hairpin radius rods with a Panhard bar controlling lateral movement up front while a 9-inch rearend swings off of a triangulated four-link. Wilwood disc brakes reside at all four corners actuated via the brake pedal arm that is mounted from the 1 1/2-inch tubular center crossmember. Engine and transmission mounts are also included for a number of combinations.
We dissected the Moal '32 T-Bar chassis recently in the studio and thought we'd point out some of the unique features that make a true torsion bar chassis different than your old run-of-the-mill transverse spring design. Take a look.
From this front, manhole view...
From this front, manhole view of the chassis, it's easy to see how much lower the front crossmember can be when a transverse spring is omitted from the equation. Thanks to a C-notch in the front framerails and the correct combination of torsion bar and arm, the same amount of suspension travel is maintained even with the lower stance.
Instead of a bulky crossmember...
Instead of a bulky crossmember (arrow) that supports the weight of the car, a drilled version is all that's required up front due to the torsion bars and their mounting surfaces taking the brunt of the weight.
The dropped axle is located...
The dropped axle is located by a pair of hairpin radius rods and a Panhard bar to ensure the axle does not move laterally.
A pair of 1-inch-diameter...
A pair of 1-inch-diameter solid torsion bars (arrows) replaces the spring. Mounted transversely in a custom crossmember below the front of the engine, the bars are 25 1/4 inches long.
Actuating the bars and supporting...
Actuating the bars and supporting the weight of the chassis are 9-inch steel arms that rest on rollers mounted off the batwings. Pete & Jakes shocks supplement the torsion bars just like a traditional leaf spring setup. The bars pass through the framerails and are supported by bronze bushings at both ends.
At the opposite end of the...
At the opposite end of the torsion bars are the stops (arrows). These rest against a hardened steel plate and can be adjusted to raise and lower the vehicle as well as to preload the torsion bar to change handling and ride characteristics.
The T-Bar chassis comes equipped...
The T-Bar chassis comes equipped with a new Saginaw 525 steering box. Similar in size to a Vega box, the 525 box is a stronger unit.
Super Bell steering arms locate...
Super Bell steering arms locate the cross steer drag links. Also notice the batwing that serves to mount the radius rod, torsion bar arm, and Panhard bar.
The 9-inch rearend is located...
The 9-inch rearend is located by a triangulated four-link and is sprung by a pair of transverse torsion bars mounted in the rear crossmember.
At 11 inches, the rear torsion...
At 11 inches, the rear torsion arms are slightly longer than the fronts and mate directly to the rear end via linkage as opposed to the roller style found up front. Note the C-notch, Wilwood disc brakes, and Pete & Jakes shocks, all carried over from the frontend.
Here's a close-up look of...
Here's a close-up look of the rear torsion bar arm. The arm can be rotated on the splined end of the torsion bar to change ride characteristics.
The right hand torsion bar...
The right hand torsion bar (arrow) passes through the framerail and is visible through the rear crossmember.
The upper bars of the triangulated...
The upper bars of the triangulated four-link serve to locate the rearend in the lateral plane much like the Panhard bar does up front.
Bronze bushings (arrow) support...
Bronze bushings (arrow) support the torsion bar at both ends.
Like the front bars, the rear...
Like the front bars, the rear torsion bars are also mounted transversely. Unlike the front bars, however, the rears meet in the center of the crossmember and measure 22 1/4 inch.
Wilwood disc brakes are also...
Wilwood disc brakes are also de facto items at the rear of the chassis.