I am using a 36 ford straight axle that was mounted suicide style. I am also using traditional steering (drag link type) via a 70's mopar steering box. I have also used split wishbones in this set up.The shackles are not stock length but slightly longer. It has been suggested that I should consider using a panhard bar in the front just to make sure that I eliminate any side to side movement. I'd like to hear from those that are using a panhard bar on their ford straight axles and perhaps any photo's or examples of what has been done on their hot rod. Your comments will be appreciated.
A Panhard Bar is a quick and cheap add on. I have a panhard bar on my t with hairpins, dropped ibeam axel and vega steering. I feel it is needed on your car because of the lengthed shackles. Good uck
If you are using cross steering, a panhard bar is a must, to avoid bump steer. If the axle moves , steering will be affected. Henry never needed one, because the steering box pushed the drag link fore and aft.
Panhard bars up front on a ford straight axle. I was hoping for some additional comments and examples. Thanks.
I have a 28 model A with a spring on top of the axle (stock length shackles) . Cross steer set up using a 1947 Ford box. I built a pan hard bar that is adjustable for length. Set the axle up with 8 degrees of caster. So Cal steering Damper, Bias ply tires. Also built a pan hard bar for the back too. The thing drives like a bullit. The thing has a speed shimmy at a about 70mph. (Wheel balance issue) The car has a Columbia rear she wants to eat up the road. If it wasn't for the shimmy I would probably already have killed myself in it. The the pan hard bar attaches to a bracket on the split wishbone about 4" behind the axle (Right side of car). Runs paralle to the axle and attaches to a bracket that hangs down about 2" on the far frame rail (Left side of the car) . I constructed the end bushings using the rubber steering rack bushings from a fox body mustang 79-93. Then used tubing and sleeves to make the pivot points. I will try to get a pic and post up. Hope this helps I found that buiding the pan hard bar adjustable for length was handy when the car was all done and at it final ride height. I could fine tune the frame so it was centered on the front axle.
tfog That's great info. That's exactly the type of information I was looking for. Thanks. Look forward to seeing the pics.
A car which has a Ford transverse spring mounted in tension as all were from 1928-41 using stock length shackles does not need a Panhard bar whether fore-aft steering or cross-steering. What is mounted in tension? The spring perch eyes are wider than the spring eyes at rest by the length of the shackles, about 2" per side, plus 1-1.75". In other words, hook up one side of the spring to the perch, pull it out to full extension shackle parallel to the floor, add other shackle, and there should be 1-1.75" gap to the other spring perch. That said, when Ford changed to a non-tension spring mounting in 1942-48 they included a Panhard bar both front and rear.
My take, and correct me if I'm wrong or have gone astray; Henry used unsplit bones. Together with the transverse spring created a triangulated axle locator system that holds it steady under load. The shackles, bushings and spring offset the rotation of the assembly created by unbalanced forces placed on the axle through the wheels, etc. When you split the bones and mount the ends of the bones to the frame, you lose Henry's triangulation, and the axle is prone to side/side movement. If there is no panhard bar to hold the axle in place, the axle will move side/side, the movement limited by the movement of the shackles. The longer the shackles, the more movement you'll experience. Since shackles are typically quite short, the movement is small. I suspect this is OK for normal driving. But for more precise/spirited driving, a panhard or other rigid locator is required. Or, mount the ends of the bones in a triangulated arrangement close to the way Henry did it to help hold the axle steady.
Found out that my caster is actually set at 10 degrees. Looks like I need to bring it down to about 5 degrees. What are most people running their ford straight axle caster at?
I don't think it matters if the bones are stock or split with regards to side to side movement. If the axle/bone assembly has enough slack at the shackles its gonna rock back and forth either way. Best example to prove this would be Ford going to a Panhard bar themselves when they decided, for a softer ride, to use a spring that wasn't stretched to meet the shackles in the 1940's. The stock wishbone in those years was still pivoting on a center ball at the X member.
51chevy PU, you do not need to run a panard rod on this style set up as long as you have a tension mounted spring like pasadena pointed out. If the length of your shackles take the tension out of the spring there are no opposing forces to locate the axle to the spring and it will slightly wallow thus necessitating a panard rod to locate the central position of the axle. The further to parallel the wishbones are the more you remove the triangulation location and the requirement for a locater bar become a factor. Running 10* caster is a no-no , depending on the tires and off set of your rims you should be able to cut down an I beam caster angle to some where in the 5* area with out encountering an issue or overly hard steering at slow speed. There is nothing wrong with mounting a parnard rod but I some cases its over kill, you must make sure that it does not pose a bind in the suspension as it travels and there is sufficient room for it to fit
Outside of a 4 link suspension, where the two parallel links basicly control fore and aft movement and the angled arms basicly control side sway (and I say basicly because I realize many more forces are at work here...) I don't see how arm triangulation relates to a wishbone suspension. With no spring (or shocks etc) installed on a Ford single pivot ball wishbone, the front axle has effectively no resistance to side movement until you get to the interference point of the ball into the cap. In my mind, a split setup would actually offer better side to side resistance (still not enough though!) as the axle would have to bend the split bones or pivot on the perch bolts for the axle to move side to side. Possible...but certainly harder than arcing on a ball mount. The original Ford center pivot is not unlike a trailer hitch in that respect...theres no resistance to side sway at all until you get to the interference point where steel meets steel. Thats why spring tension or a Panhard bar is so important to the design!
We old farts have argued this question locally for quite a while. My nickle opinion is that even on a car with cross steering and split wishbones, there would be so little movement because of the shackles on a car with a tension mounted spring that a panhard bar that wasn't exactly the same length and exactly paralell to the drag link could cause conflicting arcs and could even cause bump steer and not eliminate it.
X2 well said. This is a taditional site and yes you can do spirited driving but with biasply tires? No disrespect to the origonal poster, but fabbing some shorter shackels would be much easier, cheaper and in my opinion more cosmetic. A taught spring IS your panhard bar. Although as a previous poster stated when the spring is mounted in tention while unweighted the ride quality is harsher, especially on a light hot rod, and when ford started to mount the springs in their normal set, not under tention a panhard was required.
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