Welded Axle Trusses ?

[Josparkz]

In my never ending quest to upgrade my vehicle , I have been considering adding some axle trusses . Most of the manufactured ones that I have seen go below axle. I feel this would get in the in the way of placing jacks and jackstands under the vehicle , important Montanans items.

A fab shop has told me they feel they can make me some good trusses and weld them to the top side of the axles . I am thinking this might not be a bad idea. However , my best thinking has some times been my undoing. As this may be a permanent addition to some expensive parts , I thought I would run it by the forums and see what kind of opinions both pro and con there may be to this that I am not aware of .



Thanks



Joe



(I wasn't really sure which forum this should be on , hence the multiple postings )

 

[Extreme1]

The only con that jumps out is that the weight of the truck will put the material they install in compression rather that tension. It would bend easier in compression.

 

[fkovalski]

The response that Extreme1 could be true if the below axle trusses are preloaded in order for them to do their job. I am not familiar with these types, but if they are NOT preloaded, then the over the top “webs” would therefore not need to be in compression either. (Are?) (Would both?) be in a static state until asked upon to do their respective jobs? I do not believe that the long leg of a web welded to the top of an axle housing would be strong enough to do its intended duty when stresses to the (end) points are applied (as in landing a jump. ) If under axle trusses are in fact preloaded, then a welded web design (over top) would have to be fastened as a downward force is applied to the ends while supported in the middle. Again, I do not believe that the long leg would hold the pre- stressed load. The situation is similar to floor joists buckling if too great a force is applied. Just my . 02 using basic geometry/ physics/ immediate stress force/ moments etc…

 

[fkovalski]

Got me thinking… what if one were to use an inverted structural “T” with the flange as the hypotenuse welded to the top of the pumpkin and the top of the axle housing? Better yet… if a channel section were to be used in the same fashion creating a box, it would be stronger. Again, not sure if preloading is needed, or if would handle the stresses being dished out.

 

[Josparkz]

Originally posted by fkovalski

Got me thinking… what if one were to use an inverted structural “T” with the flange as the hypotenuse welded to the top of the pumpkin and the top of the axle housing? Better yet… if a channel section were to be used in the same fashion creating a box, it would be stronger. Again, not sure if preloading is needed, or if would handle the stresses being dished out.

We were talking about using a "T" shape.

 

[Paychk]

Aside from the issue of will an over truss do what you want, verses an under truss. The question I would ask is what affect will welding on the axle housing have on alignment of the bearings at the end of the axle tubes? What measures would be used or needed to ensure that the precise relationship of the bearing mounts at the end of axles isn't changed by heat induced warpage?



Just food for thought

 

[Josparkz]

Originally posted by Paychk

Aside from the issue of will an over truss do what you want, verses an under truss. The question I would ask is what affect will welding on the axle housing have on alignment of the bearings at the end of the axle tubes? What measures would be used or needed to ensure that the precise relationship of the bearing mounts at the end of axles isn't changed by heat induced warpage?



Just food for thought

I don't really know the answer to the first part . (Come on now , all you engineers )

The second part though , I can probably answer. We were talking "stitch" welding , as opposed to a continuous weld. If that is done a little bit at a time , on opposite side of the truss , and not allowed to get too hot , warpage should be kept to a minimum.

 

[Josparkz]

TTT

 

[TPlasek]

If you weld to the center cast iron pumpkin, clean it, preheat it to 350F, and use a 99% nickel rod to weld the steal to the cast iron. One of my good friends owns a custom off-road shop here. I help out there on a routine basis. We have made many over the top trusses welded to both , the axle tubes, and the center section. We often make a 4 link suspension or tie in a wrapup bar to the axle truss also. The leaf spring wrapup actually starts at the center section. We found if we didn't eliminate it there, we and customers had the tubes twisted out of the center section. We also started welding the tubes where they go into the center pumpkin.



Since this is our second job, we can be choosy on what we work on. We only work on one Dana 60 equipped vehicles with 40" tires or bigger, so what we make has to stand up to tremendous forces...