Fab 9 Backbone?

[REDLYNER]

I'm currently running a pretty bare rear Fab 9, just link mounts and air bump pads. Instead of re-doing my mounts by adding a truss, would adding a rear backbone be a happy medium? How high are the risk levels of warping the tube with all of the welding?

Something like this:

 

[braxton357]

A backbone is as smart or smarter than a regular truss for racing...one that doesn't go all the way to the bearing cups is kind of a waste though. The risk of warpage is actually probably less than welding link mounts on, assuming you know how to weld using a proper heat range and take your time. What size are your tubes?

 

[Hokie_YJ]

I just put that same truss on a factory 9" housing that's going in my new buggy. I had to chop it up because the housing is offset, but it worked great.

I'm no pro by any means, but I took my time, and moved around to different spots welding. I checked it the best I could and I can't tell that it warped it a bit.

 

[MetalCraftSolved]

If it were mine, I'd strategically weld a few inches at a time, over the course of a day or two.

 

[ol'Jeeps]

Im pretty sure, as heavy as the rear housing construction is, that truss wouldnt pull that rear end unless you got it stupid hot.

Best bet, if you are concerned, is to stitch it at random points along the truss. Then randomly connect the stitches. That way you are never concentrating heat in any one spot. This is how I have always welded long welds to control warpage. I have welded many a truss and have never seen one pull an axle out of line.

(also...if you have ever had to straighten a bent axle tube, think about how much heat it took and even then it had to be quenched to cause the axle to pull very much!)

 

[braxton357]

There is zero doubt that if you weld a continuous 20" of fancy mig bead truss down one side then actually put an alignment bar in that housing...it will be far from "straight". The question is how much you really care about your housing being a little off.

 

[REDLYNER]

There is zero doubt that if you weld a continuous 20" of fancy mig bead truss down one side then actually put an alignment bar in that housing...it will be far from "straight". The question is how much you really care about your housing being a little off.

I care a lot. Most of the failures I see come from slightly bent housings constantly eating up the internals.