If there's one thing hot rodders have, it's a lot of options. Which options you choose depends a lot on your priorities. Are looks more important than comfort? Is performance more important than budget?
One big priority for a lot of hot rodders these days is traditional styling. Traditional is synonymous with "early." Unfortunately, "early" can be synonymous with outdated technology. And outdated technology can be synonymous with failure, especially if being able to drive your hot rod is also a priority.
This is especially true when you're talking about suspensions where, in addition to style, your choices will affect performance and, most importantly, safety. If it's only about traditional appearance, then wishbones are at the top of the list. Split 'bones were the prominent suspension choice during the first years of hot rodding, and still look great on early cars. When it comes to performance, however, look for those 'bones at the opposite end of the list.
The problem with split wishbones is that they have to take a lot of twist, especially when driving on uneven roads or making turns into driveways and similar conditions. If the limited articulation can't handle the stress, you end up with twisted, bent, and broken parts.
A four-bar system beats those 'bones every time. With a pair of lower bars to locate the axle front to rear, and a pair of upper bars to control axle rotation and hold the pinion angle stable, plus a Panhard bar controlling side-to-side (lateral) movement, this type of suspension has all the advantages except one. Which brings us back to style. For many traditional rodders, four-bars, like IFS, is a style about 20 years too late for a Fifties-influenced rod.
Some creative rodders have figured out how to have the best of both worlds by building a triangulated four-bar system using wishbones as the lower arms of the setup. On a triangulated four-bar, the upper bars are angled from the frame rearward and inward, closer to the center of the axle. The angle helps center the rearend, eliminating the need for a Panhard bar-which opens up room for the exhaust and other components.
Believe it or not, we were at Hollywood Hot Rods the very day Ryan Rivers and Troy Ladd were building a triangulated four-bar system for a '32 roadster, using wishbones for the upper and lower arms. The upper bars are mounted out of sight, inboard and high on the 'rails. The lower arms are mounted in plain view, where they have all the appearance of split wishbones. Looks old-timey. Works new-timey. It's win-win for hot rodders who like tradition and performance.
These Ford wishbones are on...
These Ford wishbones are on the way to being transformed into upper and lower four-bars for the roadster, using the accompanying tie rod ends, sleeves, bungs, and bushings, plus some fabricated sheetmetal brackets. The '36 rear 'bones will become the lower bars and the shorter '35-41 front 'bones (on the right) will become the upper bars.
Here, the smaller-diameter...
Here, the smaller-diameter 'bones, which will be the upper arms, have already been cut to fit. The tapered end (left) will be bracketed to the frame and pivot on a urethane tie rod end from SO-CAL Speed Shop (shown on the left). The other end will be bracketed to the rear axle and pivot on a urethane bushing in a steel sleeve (on the right).
Troy Ladd drilled the axle...
Troy Ladd drilled the axle end of the upper arms for the steel sleeve that will hold the bushing.
Instead of leaving a portion...
Instead of leaving a portion of the upper arm extending beyond the sleeve, he instead chose to cut the arm right at the sleeve for a cleaner look.
Brackets were fabricated from...
Brackets were fabricated from 1/8-inch cold rolled plate to hold the forward end of the upper arms to the boxed framerails. The bracket is tack welded here, but will later be welded, of course. The tie rod ends with urethane bushings are more contemporary looking than the overall theme of the roadster, but they will be invisible after the body is dropped onto the frame.
A smaller pair of tabs was...
A smaller pair of tabs was built, also from 1/8-inch plate, to mount the upper arms to the rear axle, just to the outside of the third member housing. These arms are fastened with a bolt, and will be plenty strong to handle the longitudinal force.
Note the section of 2-inch square tubing stuck between the axle and the C-notch in the frame (arrow). These were used on each side to establish the proper ride height and pinion angle while Ryan accurately located the upper and lower arms. The mounting tabs at the front and rear of these upper arms were sized to keep the front and rear pivot points horizontal (and the arms parallel to the ground) at ride height.
The larger wishbones were...
The larger wishbones were cut to length for use as lower arms, and are fastened at the front pivot points on the outside framerails with standard early Ford polished stainless steel tie rod ends (for a more traditional appearance) and weld-in stainless bungs.
The framerails were drilled...
The framerails were drilled the diameter of the bungs, which were cut the exact width of the frame, and will be welded on both sides of the 'rails.
The bung diameter is large...
The bung diameter is large enough to get a socket into the inside of the framerail to reach the nut. The castle nut shown in this photo was supplied with the tie rod end, and used temporarily while mocking up the arms, it will be replaced with a self-locking Nylock nut at finally assembly.
The rearward end of each lower...
The rearward end of each lower arm was drilled and sleeved for the urethane bushings that will provide the lower rear link points.
This will be out of sight...
This will be out of sight when mounted.
The lower arms are fastened...
The lower arms are fastened by a bolt to pivot on rear axle brackets that you're about to see made. Notice that one of the yoke flanges was ground off. The other has been retained and will eventually be heated and bent into position for use as a lower shock mount. After being ground and dressed, it will look great.
In addition to the relatively...
In addition to the relatively simple brackets that mount the upper bars, Ryan designed and built the brackets that will connect the lower bars to the rear axle.
Our spatial skills not being...
Our spatial skills not being what they used to, we had a hard time envisioning how those assorted pieces of plasma cut, 1/8-inch steel plate would become a pair of brackets until Ryan mocked it up for us. The straight lower portion will hold the lower bar; the curved upper portion and the thick-wall tubing at the end will hold the spring perch for the Model A high-arch leaf springs. They meet at the axle. When welded, the curved I-beam design will be very strong but also lightweight.
As with a lot of fabrication,...
As with a lot of fabrication, perfectly fitting the long, curved bottom piece of the brackets involved a combination of eyeballing and trial-and-error, helped by Ryan's experience in working with sheetmetal.
The brackets were tack welded...
The brackets were tack welded and temporarily mounted on the axle, with the lower arms in position. The square tubing is still in place to set the ride height. The drop in the rear brackets that holds the lower arms was determined carefully to make sure the lower bars are parallel to the ground at ride height. In this case, it's approximately 4 1/2 inches lower than the axle centerline.
This matches the position...
This matches the position of the front pivot points where the lower bars connect to the framerails so that-like the upper arms-the front and rear pivot points are horizontal at ride height. As you can see, this photo was taken before the spring mount was cut from the lower four-bar.
Here is the welded bracket...
Here is the welded bracket with the shackles (from Reid's Rod Parts), springs, and lower four-bar in place.
The four-bar suspension not...
The four-bar suspension not only looks good, it will provide reliable performance. When the body goes back on, and only those lower bars are visible, people may think the roadster is running split wishbones. Only you and I will know the truth.