im thinking about making my own traction bars, i was looking at the truck pictured below and im thinking something like that but.

how do they know the angle?
mounting point on the frame?
length of the bar?

all of those have to play in with the factor of how they work and there application i would think?

any ideas? type of formulas or rule of thumb?

 

mounting on the frame just find a decent spot make brackets then use hiem joints on pan harded rod then make a backet thats bolts to the u-bolts ontop of the diff

 

^^ what he said!

 

I think i've seen ladder bars are generally pretty good. Try google for ladder bars and see what you can find out.

 

Well, any spot is not good.

Consider the geometry of the axle flexing based on your leaf-sprung suspension (or coils and trailing arms if you've got them back there).

The traction bars MUST pivot the same as the front spring attachment point, or very close to it (that is, it should be approximately parallel to the leaf spring). Failure to do this will make a system with will bind or break, unless you build a LOT of give into it, which would defeat the purpose.

Look at how pivoting (Duff style for instance) traction bars are mounted. The attachment point is very close or ON the front spring hanger.

If you end up with unequal length "levers" (the spring and the traction bar), this will try to exert a torsional force on the axle which will bend either the spring or the traction bar. Probably the spring, lol.

Because the hanger-to-axle-center distance changes a bit as the spring flexes (flattens and recurves), there is no PERFECT attachment point for leaf vehicles. The idea is to minimize the error, and resultant stress, on the system by picking a front pivot point which makes the traction bar as close to the length of the front hanger to axle center as possible, and as parallel to the leaf spring as possible.

That's the optimum geometry.

 

so if they need to be parallel to the leaf spring does it have to be mounted to the top portion of the spring? so possibly i could mount the bar to something in between the axle and the spring pack. (say some type of Block with a mount ) then come forward and mount something to the outside of the frame. which would be very close to parallel?

for instance something along these lines.

 

yeah. those are ladder bars.
The front mount is going to have the heim joint. the rear mounts just need to bolt to the axle...common to use mounts that utilitize the u-bolts, but it has also been done by welding a bracket to the axle tube (only recommended if you have an expert welder)

 

The line drawn to the axle attachment center point, from the frame attachment center point, should be near parallel. It doesn't matter whether the bar is above or below the spring.

That requirement seems to be met by the picture you posted.

Any misalignment is made up for by "give" somewhere. In the Duff small traction bars, the poly bushings allow the "give". Too much "give" will allow an axle to move too much.

To clarify: the LENGTH of the bar needs to be considered based on the center of the axle, and the pivot point of the spring. WHERE you position the bar, above, or below, you need to make it as parallel to the leaf spring as possible to minimize stress when the suspension cycles.

 

awesome. well im gonna take some measurements and see what i can come up with.

 

lemme know all the stuff to buddy..and how it works..might be intrested in a set..and if there not a pain in the *** to make...might make a few

 

will do.

 

If you care about articulation, ladder bars are not the hot ticket.

Typical ladder bars rigidly mount to the axle on both sides and in multiple locations, forcing both bars to move together in parallel. The only differential between right and left is what is allowed by the compression of the isolation bushings and the deformation of the axle and bars. The effect offroad is to turn the rear axle into a massive anti-sway bar.

Traction bars need to pivot at both the axle and at the forward mount to allow much independent motion. JD's above axle bars do that.

During extreme articulation, even a dual pivot traction bar can bind up when twisted. JD uses a cheap/clever way around that problem by allowing the front of the traction bar to pivot AND rotate.

JD above axle bars:




JD short ladder bars:

 

the thing i was trying to avoid were those JD bars above the spring. Reason is i didint want to mess with modifying them after the chevy leaf springs are in. i know you have modified yours to work and it looks like a good solution just wasnt what i was looking for.

those ladder bars mount to the side of the frame. so im thinking use those beacuse it wouldnt effect the chevy leaf spring swap. but i understand that it will loose articulation so i guess either wheel hop and articulation or less articulation and no wheel hop.

i just have a feeling after gears and bigger tires, wheel hop will become more of an issue.

 

Keep in mind I'm using the JD above-the-axle bars with my 4.56 geared, 35 inch tire Ranger. Wheel hop is minimal.

 

Zach, it sounds like you're saying that it would be easier to design and build a set of ladder bars than to lengthen a set of JDs. (??)

 

ah maybe it intrests me more to make something.

might not make sense but sounds like fun. lol

 

cool, im thinkin about makin a set as well. I gotta talk to my old man and see if he can copy the bracket again...he did it once so well see.

 

im gonna do some trac bars sometime.. hopefully... ill prob just end up buying some