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Big Blue's Step Bars Or Rock Sliders


Gary Lewis

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Bob - No problem, assuming you now understand how it is all supported.

On the position of the rocker protection, yes the top of the step is 3" below the rocker.  We like that position even though we are giving up ground clearance, and don't really want to raise it.  So would like to put the rocker protection piece at the same height as that will make it easier to assemble.

But the issue I'm trying to work through is how to attach the ends of the E to the mounts on the frame.  As previously said it looks like the top of the step tube is about even with the bottom of the mount in front, so I could just somehow connect the ends of the E to the mount there.  And I can remake the rear mount so the bottom of it is at the right height.  But how to connect the ends of the E to the mount is the real issue.

If the step tubing is 2" then there's a big mismatch and it isn't easy to see how to connect them with a lot of strength.  If the tubing is 3" I could bolt through both the step and the mount and have a pretty strong mount.  But, if the step tube were to slip inside of the mount then that might offer a strong connection, and a 2 1/2" tube would be a nice fit inside the 3" mounts given their 3/16" walls.  However, that means I have to make new front mounts.  :nabble_thinking-26_orig:

But part of the equation has to be the strength of the step tubing itself.  I found this RogueFab site that has a tubing strength calculator so need to play with that a bit to see how large the tubing needs to be in order to be able to support the truck, even in a dynamic-loading case.  :nabble_anim_working:

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40 minutes ago, Gary Lewis said:

But how to connect the ends of the E to the mount is the real issue..... If the step tubing is 2" then there's a big mismatch and it isn't easy to see how to connect them with a lot of strength.... I need to see how large the tubing needs to be in order to be able to support the truck, even in a dynamic-loading case.  

I'd suggest a triangular gusset from the top of the E (above one wall of the tube) all the way to the top flange of the frame. While a C shaped frame rail is not optimal in torsion (which is what you're doing with the slider as a lever) at least that brings the other flange into play. Nothing is going to support 3-4 tons dropping it into a rock, and they're going to end up pretty heavy even in 3/16 tube.

Have you figured out how you're going to get the spare out of the bed yet?

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Jim - I do plan on having triangular gussets going up the 1/4" plate from the top of the mount to the top of the plate, as shown below.  The only issue is that they have to clear the rib on the cab.  So I plan to have two of them, one at the rear of the mount and one at the front.  Is that what you mean?

And maybe we are getting our terminology crossed up.  By "step" I'm talking about the tubing that will form the outside of the E, and by "slider" or "rocker" I'm talking about the tubing that will be under the rocker.  I'll draw it up after church and maybe this will be clearer.

As for "dropping", I don't think we'll be doing that.  At least not rapidly.  What happened in Arkansas was that the trail went between two sections of a tree that was down and the cut was essentially the same width as Big Blue.  I misjudged the placement and the left step, or more accurately "running board", which touched the tree.  We didn't feel it in the cab, but heard a squeal that must have been the tree sliding down the tubing.  :nabble_smiley_blush:

So I want steps that will take that kind of abuse and then some.

Again, I'll draw this up later today and, hopefully, we'll all understand it better.  (I know I don't understand it well as I drew up something earlier this morning and discovered it wasn't even close to right.)

 

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