I have an original 55 Chevy gasser from back in the early days that I’m bringing back to life. It has a jacked up a-arm, front suspension and big Olds rear. I like the look of the long early traction bars, but want to drive the car on the street. The issue with the solid bars binding, of course, is that the 3 inch axle tubes will not flex like an early Ford front axle does when the car leans in a turn. Something has to bend or break. I have a set of caltracs but they are too late for the car. I wondered if I could use long, solid ladder bars that mount with two heims at the rear axle and a heim at the front, but just leave the bolt out of the upper heim on the street, making it work like a lower 4 bar while the spring acted as the upper one? Similar to the Caltracs. At the track I could reinsert the upper bolt for straight line action. I will build them from scratch and design the rear mounts to capture the heim between plates and compute the lift point with and without the bolt in place. Anyone done it, or have ideas?
If it still has parallel leafs, you'll still be trying to pivot the rear axle on 2 different arcs. I have some home made traction bars similar to Cal Tracs and the bellcrank doesn't show from the side so they kinda look like Traction Masters. They hit with a very short urethane snubber so they aren't harsh on the street and there's no bolt to remove. Gary
I made some also...work like cal tracs, look like traction masters. Pretty simple to do, just make the front plates L shaped instead of triangles.
This (in red above) sounds a bit dangerous to me. Do a simple, single bar like Squirrel's suggestion above. With many...choices available, but with your thought of staying in the "old" category, this seems to me would be your best bet. This style was used by many traction device companies back in the day. Studebaker even used them on their supercharged Avanti's and Larks. Mike
OR you could run a full floating setup with the spring and ladder bars. If the car had any serious horsepower I'd full float it and be done. ...
Ladder bars with sliders still do not allow body roll or one wheel dropping, etc. If you don’t agree, anchor one side of your ladder bar and pull the other one down or up (hint:you can’t!). . Not good for the street.
Floaters on the spring mounts, long ladder bars, then you only need to remove the top bolt on one side for street use.
I think the floaters would defeat the purpose of having the spring act as the upper bar. While it is true that the solid rear mount at the spring cannot pivot, the minuscule angle of movement is so small, the spring bend could easily take care of that, exactly like the old drag master bars.
Yes. Springs are just springs. The ladder bar with all bolts will locate it fully, and the other will locate the front to back a bit with only the two bolts. Should give more articulation on the street. Just an idea, I’ve never tried this setup.
If you are building it traditional,let it handle traditionally. Or make everything else traditional and let the suspension break tradition and work well. More drivable and safe on rhe street trumps tradition in this case IMO.
The problem I foresee with this set up would be that all of the lift would be on one side of the car. Seems like it would kick the car sideways pretty quickly or at least lift one side, making traction very uneven.
You must let the traction bar move fore and aft freely while preventing it from moving up and down to prevent spring wrap. I do it two ways. One is to weld a 1/2" pipe in the front of the ladder bar. That pipe stabs into a MII rubber trailing arm bushing allowing the ladder slide fore and aft but not up and down and rotate inside the rubber and not bind the leaf springs. Just need to weld up a cup to contain the rubber. Second is to make a shackle for the front of the ladder letting the ladder swing freely fore and aft while again, restricting up and down spring wrap.
I have run a single traction bar on everything since 1964. I had a 327 powered Chevy11. All it would do is spin the tires. I mounted a single 50 Olds bar on the right side and shackled the front using a Chevy11 shackle. There is no bind and I got rear end lift and equal traction. Mount the bar in the ratio of the rear end or more. Mounted width versus length is say 4 to 1. Look up Andy Rafferty roadster to see if I have used the design some. I submitted a thread on the design but forgot what I called it. I really dislike the old traction master design as if removes the factory anti squat result from having the front half of the spring stiffer than the back. With the traction master design the rear has to move without rotating and loading the front of the spring. I tried it and thought it was terrible. I actually got less traction with it than stock. The dynamics is like a four bar. No anti squat. The rear will drop on acceleration. I like the rear to remain at height or come up some.
I don’t think I’m completely explaining myself well. I am not worried about the front rear intersecting arcs being an issue. A slider or the shackle easily fixes that. What I am talking about is the fact that when the body rolls in a corner, one side of the traction bar must go up while the other one goes down. This is impossible if both of them are fixed securely at the rear to the axle. Picture, a rear end with the traction bars attached, but outside of the car. If you lift one traction bar, the other one necessarily lifts. Same thing happens when it is installed in the car. In a four bar system, both ends of all four bars are free to move independently, which allows one side of the axle to lift without the other side having to lift. That is what I’m trying to cure.
If you're wanting looks just make 2 ladder bars parallel [but use soft rubber eyes instead of heims] Mitsubishi did this on oil spring 4 x 4's [Pajero] It is not ideal This sort of bullshit ^^ [posted above] is misleading The spring does not Arc forward at the axle, it travels vertically [the spring lengthens as it compresses counteracting the arc]
During bodyroll articulation there was enough compliance with all 6 [in opposite directions to each side] When all the loads are in unison [axle wrap or thrust] the movement is minimal Land Rover's also have the same suspension [ignore the funky sway bar] The only difference is you want the rear bushings vertical [for appearance] instead of horizontal. The distance between them should be the same either way. There is also a way to build rubber mounted ladder bars with rear locking pins [clevis pins] for strip use
OK , I'll do some math for you. If you have a vehicle that is 60" wide [at the axle] and there is 4" body roll on a corner [2" up on the inside, 2" down on the outside] Which is a lot. This is 3.82° body roll Now lets assume the ladder bars are 42" apart [and parallel] 42" at the front of the ladder bars at 3.82° body roll = a height difference of 2.8" [1.4" up on the inside, 1.4" down on the outside each side of the centerline ] So the inside ladder bar needs to bend 1.4" up, and outside ladder bar needs to bend 1.4" down at the front pivots. If the ladder bars were 48" long [Gasser style] 1.4" up/down = 1.67° rotation from the axle centerline The inside ladder bar needs to bend up 1.67°, and outside ladder bar needs to bend down 1.67° If they were traditional triangle ladder bars with the mounting brackets 8" apart [eg: 4" each side of the axle centerline] The bushing will need to compress 1.67° forward and 1.67° aft 4" x 1.67° = 0.12" [less than 1/8" which is easily handled by a rubber bushing] This would be an easy compromise to look period correct .And you don't need to "over think" it [like I just did ] Edit: The Arc of a 48" long ladder bar over 2-1/2" travel is only 0.070" The front eye on the leaf spring [and ladder bars] could handle any potential binding
I build a torque arm that is much like two close ladder bars with a common front eye, nose attaches with shackles to a bracket above the driveshaft, no bind and allows articulation. Easy 1.30 60's with this setup... The bracket above the driveshaft uses machined hockey pucks to isolate the chassis from rearend noise... Doesn't exactly look traditional, but solves the problems. Effective on both the drag strip and street... Grant
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