Best bang for the buck traction bars?

[UNBROKEN]

I think they are both well built functional products.

I wholeheartedly agree.

 

[UNBROKEN]

So there is ZERO binding with a fixed bar. Correct?

I have experienced none and the truck rides phenomenally well. I had 7 different people in my truck this past weekend and every single one of them commented on how well the truck rides and how composed it is.

 

[CATDiezel]

***Preface*** I'm no engineer, but I play one at work sometimes.

An axle mounted on leaf springs does not move in a radial path. It actually moves in a funky elliptical pathway; meaning at some point in its travel it is closer or further away from the traction bar mount.

OUO addresses this by using elastomeric bushings at the forward end of the bars where they mount to the frame brackets. This keeps the pinion angle more constant during the axle's travel path.

Using fixed mounts assumes the pathway is an arc around the attachment point. What actually happens is the pinion angle changes during the axle's travel path.

Floating bar designs address the virtual pivot by allowing the forward end to move fore and aft.

Ahh. I guess I should have backed up and looked for a very key set of words...

ELLIPTICAL PATHWAY.

Now I can sleep without pondering any longer. I simply agree. Best set of words I have seen used so far. And with the rubber bushing on the front of the bar that allows the elliptical movement to continue (albeit some what stiffened)

 

[Coueshunter]

Very valid points Layson. I don't do lifts or suspension modifications anymore. However I have been paying attention to traction bars lately and wondered the same thing being the rear suspension (rear axle) angularity is perpendicular by nature(to the frame). Adding a stiff support bar would basically make a stiff triangular setup and the point of force would be displaced between the bolts at the frame and the axle.

Now that would be the case with a leaf spring solid mounted but that's not the case. A leaf spring has a rear shackle allowing for any aft force in compression. Because of that movement at the rear leaf spring mount, wouldn't the leaf then still follow the same arch in a compression dynamic.

A shackle has 1 primary function. It allows for the leaf spring to work through length changes during suspension articulation.

 

[c63 AMG]

So for PMF do I have to put the truck on jack stands and jack under the diff or can I leave the truck sitting on the ground and install?


Sent from my iPhone using Tapatalk

 

[CATDiezel]

Now that would be the case with a leaf spring solid mounted but that's not the case. A leaf spring has a rear shackle allowing for any aft force in compression. Because of that movement at the rear leaf spring mount wouldn't the leaf then still follow the same arch in a compression dynamic.

Here is the problem with forum collaborative discussions. And the same reason "go to meeting" to this day still has not replaced physically meetings in the business world. Too much to type! Haha.

I believe betarocker explained it best and you probably replied to my comment while I was typing the next comment.

ELLIPTICAL PATHWAY (thanks betarocker) that is dynamic and unique per truck according to load in bed and a few other factors such as quality of leaf... ect. My leafs are probably somewhat different than your being it is very hard to duplicate the same leaf with flawless repeatability. Although very close. It would be safe to say very few are the same as the steel quality changes somewhat and heat process can vary slightly from one month to the next. Alot of variables.

That equates to why one truck sags in another area where others dont. But. I'm just pointing out simply the minor differences in each trucks suspension.

This conversation has gotten extremely technical but I also enjoy it because it's what makes PSARMY unique to the other generic forums.

As a kid they had these cool stencils that were geometric by design and you could stick a pencil in them and draw ellipticall circles with the angle of the oval changing with every full revolution. Now add in small ovals and large ovals and you have the rear movement of a Ford rear axle!.

(I had to run out to my shop and look at the rear axle real quick! Haha.. I don't spend much time starring at the suspension)

 

[Coueshunter]

I have experienced none and the truck rides phenomenally well. I had 7 different people in my truck this past weekend and every single one of them commented on how well the truck rides and how composed it is.

I get that... But we seem to have to start at ground zero around here to dispel some myths.

 

[UNBROKEN]

So for PMF do I have to put the truck on jack stands and jack under the diff or can I leave the truck sitting on the ground and install?


Sent from my iPhone using Tapatalk

On the ground is fine if you like.

 

[CATDiezel]

On the ground is fine if you like.

I would agree that you would want to install them at the average "down the road" ride height to achieve a mean average of ride quality... for either brand.

 

[NotStock]

So for PMF do I have to put the truck on jack stands and jack under the diff or can I leave the truck sitting on the ground and install?


Sent from my iPhone using Tapatalk

Frame bracket and bar length is setup with the truck sitting at normal ride height. No preload should be added.

 

[Jomax]

So the rear suspension working in conjunction with the shackle works perfectly as designed with a fixed set of traction bars.



There would be no binding because as the travel of the lead spring goes up it would push the shackle back. In fact if you mount a go pro on the rear frame you'll see that the leaf spring also moves in an arc when compressed from a bump. It doesn't just go straight up and down.

It's pretty simple, the axle moves down and forward on down travel. If you have fixed bars, the axle is not allowed its natural travel path any longer.

Same concept on why a 4 linked front end on these trucks isn't the greatest.


Sent from my iPhone using Tapatalk

 

[m_j]

So there is ZERO binding with a fixed bar. Correct?

incorrect.

 

[m_j]

Now install that fixed traction bar. The leaf spring will still act the same way. It is not limited by the path or arc of a fixed bar as there is a moving shackle that will now deflect as the leaf spring compresses allowing the leaf spring to act normally.

the spring is limited by the fixed bar, everything else you typed is based on flawed logic.
if the bushng deflects enough to reduce the bind it also reduces its ability to prevent unwanted suspension motion, its bind by design.

this is a ridiculous topic to try and argue.
this design is a cheap easy part to sell at a big markup, super easy to package and pretty much universal application
I would never waste my time putting one on my vehicle.

 

[Coueshunter]

It's pretty simple, the axle moves down and forward on down travel. If you have fixed bars, the axle is not allowed its natural travel path any longer.

Same concept on why a 4 linked front end on these trucks isn't the greatest.


Sent from my iPhone using Tapatalk

There is a shackle.. What is the purpose of the shackle then?

 

[Coueshunter]

the spring is limited by the fixed bar, everything else you typed is based on flawed logic.
if the bushng deflects enough to reduce the bind it also reduces its ability to prevent unwanted suspension motion, its bind by design.

this is a ridiculous topic to try and argue.
this design is a cheap easy part to sell at a big markup, super easy to package and pretty much universal application
I would never waste my time putting one on my vehicle.

It wouldn't be a bushing that deflects to stop bind. That would be a claim for an OUO bar.

What is the sole purpose of the leaf spring shackle then? Wouldn't all aft deflection be adjusted appropriately by deflection in the shackle? If not, why?

 

[NCSU dirt man]

I'm pretty sure both Trevor (with PMF) and Jared (with OUO/Midwest) are probably having a good laugh at everybody expense right now who's trying to play the part of "suspension guru." both are great products designed to serve the same purpose; each has it's own strengths and potentially "drawbacks" in certain peoples' minds. Debates like these have always made a prospective buyer like myself a little leery of purchasing either brand though. So those of you bashing one brand/design for another brand/design might want to consider the potential damage you're doing in general to the other brand's business as well as the image you are portraying for the brand you're defending. we're all entitled to our opinions but you never want to hurt the company you're a fan of...

 

[Jonnydime]

Now that would be the case with a leaf spring solid mounted but that's not the case. A leaf spring has a rear shackle allowing for any aft force in compression. Because of that movement at the rear leaf spring mount, wouldn't the leaf then still follow the same arch in a compression dynamic.

A shackle has 1 primary function. It allows for the leaf spring to work through length changes during suspension articulation.

Remember the shackle is only on the rear of the spring pack. So you have a fixed pivot point at the front of the spring and a movable point at the rear now when you compress the leaf spring the leaf pack gets longer not only in the back but also the front of the spring as well. Under normal operation the axle would move towards the rear of the truck. When you add a traction bar you now add another fixed pivot point and if the path of motion is different you will get a bind in the suspension.

 

[Betarocker]

It wouldn't be a bushing that deflects to stop bind. That would be a claim for an OUO bar.

What is the sole purpose of the leaf spring shackle then? Wouldn't all aft deflection be adjusted appropriately by deflection in the shackle? If not, why?

The shackle is part of the spring system. Without it, the spring would not be able to move. It isn't part of the traction bar system.

"A shackle is an integral component of the suspension system that attaches between the leaf spring and the vehicle frame. It allows for the leaf spring to work through length changes during suspension articulation. The leaf packs, or leaf springs, position and center the axle under the vehicle. They also support the vehicle's weight, since these are a primary component of the suspension system. As a leaf spring flexes up or down, its length from main eye to shackle eye changes. Since one end is mounted solidly (the main eye), and cannot move, the length changes happen at the shackle end of the leaf pack."

 

[JRLott]

This academic discussion is fun to watch. It's not all that relevant since both companies make fine products that have been proven to work, but it is mostly irrelevant argumentative bull****.

 

[Coueshunter]

Remember the shackle is only on the rear of the spring pack. So you have a fixed pivot point at the front of the spring and a movable point at the rear now when you compress the leaf spring the leaf pack gets longer not only in the back but also the front of the spring as well. Under normal operation the axle would move towards the rear of the truck. When you add a traction bar you now add another fixed pivot point and if the path of motion is different you will get a bind in the suspension.

The rear part of the spring is for rate, the front part of the spring merely controls wrap.

With that in mind, a traction bar does nothing to hinder the operation of the back half of the spring as compression will be adjusted by shackle movement.