M416 extended the tongue (1 Viewer)

[hey you]

I extended the tongue on my M416 last year copying some of the other builds here on Mud and on the Expedition Portal. I wasn't entirely thrilled with my build. I didn't have any problems or failures but, I was afraid that I would have a failure at the draw bars and the front cross member on the trailer frame.

So, I took most of it apart... I am questioning the ideas as to how to reinforce the draw bars? The front cross member on the frame was replaced with 3x3x1/4" tubing. I then welded on the original draw bars and added a receiver tubing 2-1/2"x2- 1/2"x1/4"- OD.

I was considering building a sub frame under the draw bars, sistering 1"x2"x1/4" rectangular tubing under the draw bars (stitch welded/gusseted) and extending them back to the original draw bar/frame members. Or, should a simple bottom 1/4" plate/gusset welded to the 3x3 frame/draw bars member suffice? I'm comfortable with my welds holding up.

Thoughts?

 

[ntsqd]

The draw bars should all go under the main frame like they originally did, not butt into the front of it. To maintain the coupler's height I would put the diagonals under the frame like original, and then place the receiver tube on top of them. Can extend the receiver tube back to the front cross-member if desired, but if the diagonal members are appropriately sized it's not necessary unless you're also extending the tongue out past where the diagonals meet. Plating and gussets simply can't even come close to duplicating the light weight strength of the original design.

 

[hey you]

You are correct! I wanted to extend my draw bars so that I could use the trailer with my FJ40 that has a 35 inch tire and basket. The extended draw bars would prevent the trailer and the FJ40 from making contact while articulating on the trail. Additionally, I wanted to carry a little weight on the tongue (100lbs) with additional gas/water/tools and. I can also extend the hitch another 18" if I want too.

So, given the existing set up, what are the best options to reinforce the draw bars and not restoring it back to the original setup?

 

[ntsqd]

The best is the diagonal arrangement that it originally had, those two tongue pieces start under the outer main rail near the front spring perch and come forward and in to meet where the lunette was. Don't have to restore it, just repeat that arrangement with steel tube, only place the receiver tube section on top of the diagonals where they meet instead of using the original casting that the lunette bolted into.

Across the front cross-member is the highest stress zone in the whole trailer frame. Putting the diagonals under the main frame radically increases the strength of the frame with very little weight penalty. No matter if gusset plates made from uber-strong steel are added, it won't be anywhere near as strong as using the original tongue geometry.

Could double up the existing diagonals with the same dimension tube underneath, but these new tubes must extend back and out to the main frame rails and be tied in there as well. If you did this the existing diagonal tubes will basically just be spacers to make the tongue flat across the top, they won't be adding much to the strength of the tongue.

I know that this is contrary to 90% of what you seen done with these little trailers. That is the problem with simply copying someone else. If they did it wrong (& this case they did!) then the error just perpetuates itself.

 

[hey you]

Got it!!! I need to head to the metal yard. I like the idea of doubling up the diagonals and taking them back to the original frame mounts in front of the spring hangers. That would keep my deck flat and the tongue extended like I wanted. I'll add a plate to the bottom of the center draw bar/front cross-member on the frame.

Also, is there any reason to add cross members to the new diagonals, if so, what would you recommend?

Yes I copied others... It still didn't look right. Thanks for your help. I'm grateful for your input.

 

[ntsqd]

The only reason to add cross-members to the tongue would be if you need one there to mount something to.