Off road trailer tongue

[smritte]

Forgot to add in.
"hitch weight ratings" These are set for street conditions. The constant up/down leverage of off-road is not factored in. Nor is leverage against the frame and suspension (off-road).
I had asked one of the trailer manufactures why they ran so much tongue weight and length. The response didn't surprise me. "We stay with in the manufactures hitch/tow rating for most vehicles." " The longer/heavier is safer to tow and the customer is responsible to make sure their vehicle is strong enough". The gentleman I spoke with was the owner/designer. I have seen similar comments posted by a few different builders.

Bottom line is, off-road uses a different set of rules than street.

 

[smritte]

My tongue is different from most, being mounted soo high. It is also longer. It has never been a problem and allows extreme articulation. I may shorten it 6 inches some day when I have time, but it has never given me any issues either on or off road.

I like your design. It covers a few different issues with simplicity and strength.

 

[smritte]

So, I got a PM asking why the trucks seem to bend in the same place when the suspension should be absorbing the shock. This includes vehicles with properly modified suspension, designed to hold the extra tongue weight. The suspension and suspension mounts should be designed to allow the frame to flex without damage. This is a very good question and I decided to post the answer for others to see.

These are true. You can factor in the comment made in the video about the shocks being too long and creating a focused "piviot", causing more fatigue in that area during a "bottom out". The same focused area can happen with rigid bump stops being slammed into.

What no one has payed attention to, was what should be obvious. The body reinforces the frame and keeps the flex to a minimum. So does the bed. The problem is, their not connected. Now we have an area that's allowed to flex, with more rigidity on both sides of it. This flexing is minimal on street and mild dirt. Add in a focal point caused by shocks, spring mounts...in the same area and the problem is amplified.

When metal flexes several things can happen.
1. The energy (heat from movement/flexing) is absorbed and dissipated as designed into the chassis and suspension.
2. Work hardening occurs. Think, bending a paper clip until it breaks. Certain metal make ups will have this happen. This is when you see cracking. Think older rigid frames forced to flex during early rock crawling or hard trail driving.
3. Annealing. This is the softening of metal. This can happen in an area where the flexing is concentrated. The gradual heat/cool from the flex being focused into an area and not spread out. The metal is softened and starts to lose its ability to retain a memory. Now it bends and doesn't return to its previous shape.

#3 is what I believe is happening between the frame and bed. Factor in everything else, including modern crumple areas and you will see something bend right there. This problem is not new. I have watched #2 and #3 happen forever. This is why we build things a certain way for off-road use.

Uni body vehicles tend to flex evenly but when modded can crack in places. You see this where something inflexible is attached to something flexible. A good example is Cherokees breaking the body/ frame where the steering box is attached.

 

[MOAK]

Forgot to add in.
"hitch weight ratings" These are set for street conditions. The constant up/down leverage of off-road is not factored in. Nor is leverage against the frame and suspension (off-road).
I had asked one of the trailer manufactures why they ran so much tongue weight and length. The response didn't surprise me. "We stay with in the manufactures hitch/tow rating for most vehicles." " The longer/heavier is safer to tow and the customer is responsible to make sure their vehicle is strong enough". The gentleman I spoke with was the owner/designer. I have seen similar comments posted by a few different builders.

Bottom line is, off-road uses a different set of rules than street.

Lots of good info there. People that don’t know almost always ask sarcastically if my 5ton pintle is big enough for our little 1/2 ton trailer. I just smile at em. My tongue is just long enough to open the swing out tire carrier. The tongue is also bolted up using grade 8 bolts. I thought about running a tongue all the way to the rear, but I do like using the trailer as a crumple zone. I may someday have a 14”x14”x48” basket fabricated and welded to the front to carry the tent and tent gear. When that happens I’ll lengthen the tongue accordingly. What are your thoughts Scott? ( crumple zone and bolted on tongue )

 

[smritte]

To be honest, I never thought about it. On my new build, I'm running light tubing but my angles are strong. If hit hard enough, I'm sure my trailer frame would "diamond" slightly and the trailer would shoot off to the side, bending the tongue. The M-100 would probably bend the tongue then shoot off somewhere.

I'm not a fan of full length tongue's. Their strong but, what are you going to pull behind the trailer? If you were putting enough weight on the tongue and needed more support, I would tie it to the front of the spring hanger. One tube straight back and two triangulating. Anything behind that In my opinion is just extra weight.

You do know, I'm going to have to study this now. I never gave any thought to someone crashing into my trailer, nor have I seen the result of it with anyone I know.
Sigh