Pro Comp bars work...for awhile.

powr2stroke · Sep 6, 2011

You're probably right Erik , just thinking out loud

Erikclaw · Sep 6, 2011

Me too.

bigrpowr · Sep 7, 2011

My pro-comps were cheap, but did the job, handled 750 rwhp with no issue but i did not beat on them off road very hard. But i could tell they were piles from the minute i got them, there just werent many options back then in 06' .

http://thumb3.webshots.net/t/30/466/5/20/53/2123520530079772083eCtToy_th.jpg

Jeff@Spartan · Sep 7, 2011

Pic ain't working Mikey....unless it's meant to be tiny. LOL

imelmo · Sep 7, 2011

I took all the crap out of this thread and moved it here: http://powerstrokearmy.com/forums/showthread.php?t=5779 .

Anymore deterring from the subject at hand in this thread will be deleted and people will get some time off. Also, if posting in the other thread, read my directions carefully.

.

jb903 · Sep 9, 2011

sorry to hear they crapped out on yah. I have run them on my truck for over a year and on my last few trucks. I have 6" lift and 35's and run the 310 as a dd and beat the hell out of my truck and knock on wood, never had an issue. Well now im sure my bad luck will roll in.

tbsimmons · Sep 11, 2011

I cant really tell by the pic. But my thoughts.
If they mount on the axle only in one point, bottom would put the bars in compression and top would be tension when you hammer on it.
If mounted in the middle I can see it bending even though mounting in one point.
The bottom would try to be in compression and the top would try to be in tension when the axle tries to rotate with a bending moment. i bet if you put a straight edge on the top bar it is bent a little also.
I bet you have some axle wrap right now with them mounted in the middle tell the top bar starts to get pulled.
i dont think would not have occurred if they were either mounted on top of bottom of the axle.

blackbetty13 · Sep 12, 2011

I'm not a big fan of anything pro-comp I have a busted shock I need to fix, and when I originally bought my rims one was bent extremely bad and had to wait on getting my rims.

Powerstroke586 · Sep 13, 2011

97singlecab said:
Is the main tube bent or just the second bar running under the main tube. The procomp bars on my 2wd 7.3L have that exact same bend on the driver side, from some one being careless putting it on a rack. They still work fine. As long as your main tube isnt bent i would just run em till you can afford a nicer bar.

Got back home and took it to the shop where i bought them and the owner went out and looked and them and said both bars were bent. the top one just isnt as bad. im gonna run them til i can either find a different bar or let the owner of the shop straighten them and strengthen them.

fordboy11 said:
What did procomp have to say?

Cant get new ones unless they break, bends dont count i guess

Charles said:
Looks like the required breakover on a hill you crested was a bit higher than the truss bar on your pro-comp bars and you shoved them into the ground and bent them.

Under power that part of the bar would likely be in tension, not compression, meaning the force would be doing exactly the opposite of what it would take to bend it like that.

You probably high-centered the truck over the bars and bent them. Whether or not you noticed when it happened doesn't really matter.

ive never had my truck high centered so you are incorrect there. you are right that i didnt notice when i bent them i know it was recently though. All my off pavement driving is very bad oilfield roads. If i would have done it off road i wouldnt have made the thread.

Im just gonna run them, for now and after i get the money i will either go with another bar (ouo, pmf, etc) or strengthen these ones.

thanks for all the suggestions guys

Jeff@Spartan · Sep 13, 2011

Sucks that Pro Comp won't help you out Cody, but I guess it's a good excuse to look in to some PMF or OUO bars.

tbsimmons · Sep 13, 2011

I would put money on the bars are not the problem, the mounting location is.
It is in the middle. Move it to the top or bottom and this wont occur because you will not have a bending moment from the axle.

Powerstroke586 · Sep 13, 2011

08stroker250 said:
Sucks that Pro Comp won't help you out Cody, but I guess it's a good excuse to look in to some PMF or OUO bars.

yes it does! i like when stuff breaks gives me an excuse to upgrade LOL

once i get all my house stuff bought i can give attention to the truck.

Charles · Sep 13, 2011

I have identical mounts as those as I actually ran across some of the pro-comp mounts years back when I built my first set of links on my red truck.

The first links I built were probably identical in length to your current ones as I used the mounts as intended by pro-comp and simply made up a set of links myself.

The links I made, in the EXACT same mounts bent in EXACTLY the opposite direction from the ones in your pictures...

They deflected DOWN every single time. I even had someone else drive the truck and I watched them from the side, and they bent down tremendously as I did not gusset them, and the way pro-comp lays them out the links are pretty long.

So.... I can tell you from first hand experimentation... the links did not try to bend upward under load.

I personally never liked the idea of them being that long for geometrical reasons, and only did it because that was how they were "designed" by pro-comp. I re-positioned the front hangars where the links would form a much better angle with respect to the leafspring arc-path and made up some links from the same tube that were a fraction of the original length and they have been on the truck for years now.

The long links made the truck ride like sh*t anyway.

SAK · Sep 14, 2011

Charles said:
I have identical mounts as those as I actually ran across some of the pro-comp mounts years back when I built my first set of links on my red truck.

The first links I built were probably identical in length to your current ones as I used the mounts as intended by pro-comp and simply made up a set of links myself.

The links I made, in the EXACT same mounts bent in EXACTLY the opposite direction from the ones in your pictures...

They deflected DOWN every single time. I even had someone else drive the truck and I watched them from the side, and they bent down tremendously as I did not gusset them, and the way pro-comp lays them out the links are pretty long.

So.... I can tell you from first hand experimentation... the links did not try to bend upward under load.

I personally never liked the idea of them being that long for geometrical reasons, and only did it because that was how they were "designed" by pro-comp. I re-positioned the front hangars where the links would form a much better angle with respect to the leafspring arc-path and made up some links from the same tube that were a fraction of the original length and they have been on the truck for years now.

The long links made the truck ride like sh*t anyway.

Charles, while you are spot on, you have to remember that these are on an 08+ truck that has very flat springs and have virtually no arc path. This could be the fact to why they bent upwards. There are a lot of variables that come into play, and one may be that they are just simply not strong enough.

Charles · Sep 15, 2011

SAK said:
Charles, while you are spot on, you have to remember that these are on an 08+ truck that has very flat springs and have virtually no arc path. This could be the fact to why they bent upwards. There are a lot of variables that come into play, and one may be that they are just simply not strong enough.

I also wondered if this guys' links did in fact try to deflect downward and the truss bar went into tension, then if under shock loading like when bouncing under power if the tensile load in the truss bar wouldn't store enough energy to actually throw the whole link in the other direction when the tires lost traction momentarily, and then upon regaining traction actually deflect the links upward.

I never saw any hint of this wanting to happen on my truck, but... it wasn't gusseted, and as you say, my springs were much shorter, therefore steeper.

SAK · Sep 15, 2011

Charles said:
I also wondered if this guys' links did in fact try to deflect downward and the truss bar went into tension, then if under shock loading like when bouncing under power if the tensile load in the truss bar wouldn't store enough energy to actually throw the whole link in the other direction when the tires lost traction momentarily, and then upon regaining traction actually deflect the links upward.

I never saw any hint of this wanting to happen on my truck, but... it wasn't gusseted, and as you say, my springs were much shorter, therefore steeper.

I think we both agree that it just a bad design. :thumbsup:

tbsimmons · Sep 15, 2011

Mounting location. Either top, bottom or both with separate bars. Not in the middle.
If you month them top or bottom they are either in just tension or compression not both.
The only way I cans see the bars bending down is if you are on it, loose traction and the suspension unloads then regains traction with some suspension travel. The bar would go from compression, tension back to compression. This of course the bar is mounted to the bottom of the axle. With it in the middle would just multiply all of this.

Charles · Sep 16, 2011

tbsimmons said:
Mounting location. Either top, bottom or both with separate bars. Not in the middle.
If you month them top or bottom they are either in just tension or compression not both.
The only way I cans see the bars bending down is if you are on it, loose traction and the suspension unloads then regains traction with some suspension travel. The bar would go from compression, tension back to compression. This of course the bar is mounted to the bottom of the axle. With it in the middle would just multiply all of this.

My links are mounted on the exact same mounts as the OP. They have been that way for years. I have towed up to or over 30,000lbs gross as well as spun miles worth of rolling burnouts at 600+rwhp, plus just general shock loading of coming in and out of traction on dry pavement on a daily basis.

With the link in the centerline of the axle with the factory block under the leafspring the lower link is in pure compression and the leafspring has some of it's compressive load counteracted by a tensile load from the axle trying to rotate the top rearward under power. With the fixed link in the center of the axle handling the tendency of the axle to push forward, the remaining torque is traslated into that tensile load on the leaves.

Having the link end mounted in the center isn't a problem.

tbsimmons · Sep 16, 2011

With blocks you might be correct, I will have to draw it out to check.
I can see it though because the pivot point is moved up the length of the block to the bottom of the spring. SO instead of a rotation of just the axle you get the axle moving forward.

TyCorr · Sep 16, 2011

Charles said:
My links are mounted on the exact same mounts as the OP. They have been that way for years. I have towed up to or over 30,000lbs gross as well as spun miles worth of rolling burnouts at 600+rwhp, plus just general shock loading of coming in and out of traction on dry pavement on a daily basis.

With the link in the centerline of the axle with the factory block under the leafspring the lower link is in pure compression and the leafspring has some of it's compressive load counteracted by a tensile load from the axle trying to rotate the top rearward under power. With the fixed link in the center of the axle handling the tendency of the axle to push forward, the remaining torque is traslated into that tensile load on the leaves.

Having the link end mounted in the center isn't a problem.

Totally different topic, are those 35's on an 18" rim? Got any more pics of that tire size on the truck. Im running 37's and think I need to go smaller for function and looks.

Anything you can abide is much appreciated.