Builds 86 Xtra Cab Build (4Wheelunderground 3 link front, 4 link rear and 3.4 swap) (13 Viewers)

[aztoyman]

@ntsqd, So....have the upper horizontal tube come straight back and through the cab. Where I have a joint.

And.........have another joint down at the base plate with a straight piece of tube between the two joints?

Here's a photo edit attempt on my phone to illustrate.

I understand the concept of the bushings allowing enough movement to prevent fractures from metal fatigue. What I don't get is how the tube is not just a moving linkage if I flip and forces are trying to fold my main hoop either forward or backward.

 

[ntsqd]

It isn't, but there are two things going for it. The extension tube is short enough that it isn't much of a lever and in a catastrophic event the cab's own structure is going to be working with it to keep everything from collapsing.

FWIW, seeing from that angle I think that the tie-in at the frame needs to be much further back. Gets back to that vector math stuff again. With the back-brace tube that vertical must of the load put into the upper joint is going to be vertical and their effectiveness at resisting the cage parallelograming is pretty minimal. With the back-brace tubes at something more like a 45° the vertical component of the load is reduced and the anti parallelograming effectiveness of the back-brace tubes is greatly increased.

 

[aztoyman]

I may end up swapping my better bed on and moving some things around back there. Thank you for taking time for this.

 

[ntsqd]

Just a thought to ponder; find one of those old school plastic bed liners that will fit the truck and run it as the whole inside of the bed with the existing bedsides held in place by a simple tube structure that also supports the bed liner. I've had this idea floating around in my head ever since a friend built a bedsides-only pre-runner that he suddenly needed to be able to use as a truck.

 

[aztoyman]

This bed was pretty beat to start with and the main reason I didn't mind hacking it up for mock-up.

I've definitely considered taking what's left of the bottom out.