OK here are some basic traction bar designs and some crude drawings to illustrate. We'll start with the CalTrac design. Post your comments, new design drawings, whatever you want. These trucks are just not equipped for horsepower and posi from the factory, so we've all gotta do something with our suspensions.



The CalTrac design is IMO the best from an engineering standpoint, for high horsepower and especially drag racing applications. When the leaf spring goes upward in the front, the lever pushes it back down, helping with the anti-squat needed for a good launch. Notice the "slapper bars" actually push upward on the front spring eye, concievably helping with the whole "anti squat" idea, but probably not in a measurable amount

<EDIT> The first files I loaded didn't come out, but I fixed them. Nevermind the "slide one.txt file at the bottom. Continuing with post #4

 

attachment just says

Slide 1 Frame mounted traction bar


nothin else there

 

no pic lol

 

Here is a frame-mounted traction bar setup. Aside from slapper bars it is the easiest one to fabricate yourself. The illustration shows that the hanger at the rear spring eye allows the rear eye to move backwards as the spring is compressed. This also moves the axle rearward (less than 1/4" by my measurement) depending on your pivot points on the axle and the frame. The more parallel your bars are, the more front-back movement.

This is where the guys that use sway-bar type bushings attached to an adjustable bar have a good outcome. The bushings deflect slightly, allowing for the to-and-fro movement. They also have a quiet bar that wont rattle.

Some use a solid mount with a heim joint, for fear the bushings won't hold up to the torque. I guess this works, too, from what the guys here say about them. I don't think I would want to restrict the movement of the axle this way. But it would probably take on a whole lot more horsepower than the bushing type, IMO

 

here is my addition...for the do it yourselfers

 

This is my set-up. I have a solid mount on the axle, and a frame mounted hinge in front, with a rubber pad (the gray piece) in-between two pieces of 3/16" steel. It's a little more complicated that it should be, but I'm always doing wierd stuff just for kicks.

Anyways, it allows to-and-fro movement of the axle, and is adjustable to 0" with the right-and-left threaded 3/4" swedged rod. I used 3/4" heim joints with a 5/8" hole for the pivots, with hardened 5/8" bolts at both ends.

When the axle "wraps", it pushes forward and the hinge hits the rubber pad, stopping the bouncing effect of the spring. If I were into road racing, I would also want another stopper at the rear of the hinge, to eliminate "brake hop", which is axle-wrap going the other direction.

 

Here's a cool article with some neat illustrations that sprayed99 came up with. They're just showing the axle from the passenger side

http://www.competitionengineering.co...s/chassis2.asp

That'll definitely give a guy some ideas

 

I don't know about anyone else but I can't see the pic it's too big