Strait tongue vs. A-frame?

['05TJLWBRUBY]

What's the general consensus on tongue preference between strait tongue vs. A-frame design for off-road use?

I have a trailer build thread started here:

http://www.expeditionportal.com/forum/showthread.php?t=30224

I am picking up some steel here in a few minutes and will begin work on finishing up the axle work and tire fitment, then start working on frame design. My question on the tonque comes to play as I run all A-frames on my other trailers, yet I see a lot of strait tongue designs here. I'm curious how they do. I see the advantages of a strait tongue for sharper turns, but wondering how well they handle and how they pull in comparison to a more stout A-frame setup? I'd planned on building a strait through design then running an A-design off the sides, but realized it will greatly restrict my turning abilities so I may need to cut it back a bit. How much will this limit my overall performance?

Thanks in advance,

Best of Luck,

Mike

 

[cruiseroutfit]

At the end of the day *when properly designed and fabricated* both should result in the exact same handling characteristics, however the single beam gives you the obvious benefits of knifing.

 

[elmo_4_vt]

Obviously the A framed tongue will be stronger using the same materials, however the rig will jack-knife sooner. I used a straight tongue because I wanted my truck to be 90deg to my trailer when camping so that I would have access to the entire back without jumping over the trailer... But I did move up to a 3"x3"x1/4" section of steel, and to have triangulation built into the body of the trailer to try and maintain appropriate support for the tongue.

In the end, its just what you feel is important for your build. There are always trade-offs.

-

 

[R_Lefebvre]

I think even when properly designed for strength, the A-frame will still be *stiffer* than a straight tongue. That's why big trailers almost always have A-frames.(?) However, for a light trailer, I don't think it matters much at all.

 

[ntsqd]

The hot spot of stress in a trailer frame is where the tongue joins the main frame. I feel that how this is done is far more important than whether an 'A-frame' or a stringer tongue is used. The stringer tongue does present a bit more of a stress reduction challenge because there is only one loading point at the front of the main frame, where the 'A frame' tongue offers two or three (stringer/A frame hybrid). If the trailer will be relatively heavily loaded given it's size then this might be a consideration. If not, then I wouldn't bee too concerned.

If we were discussing a heavily loaded tag trailer, then the inherent stability of a full length 'A frame' tongue would become important, but at the loading levels of a small trailer I do not see this as a potential problem.

After you've plotted out what the tongue length needs to be, I'd suggest looking into making it a hybrid tongue with the 'A' portion designed to clear the tow vehicle when jacked to 90* If you can't, then you can't, but if you can then it is worth doing.

 

['05TJLWBRUBY]

Thanks for the info so far. I got my steel and I need to get out to the garage to get to work, but I guess I should lay out my plans for the tongue so it makes sense, if it will help with the advice at all. It will basically be overbuilt for what most consider a standard trailer-simply due to the area I'm using it and what I'm doing with it. My other trailers are getting beat up so I'm building this one to handle the abuse a little better. Probably overkill, but I don't want to keep rebuilding this one like the others.

Main frame is 2x4 rectangle tube with a couple cross members, and a receiver tube running full length from the rear bumper/crossmember clear through to the front for the LNR hitch. I'd planned on attaching the A-frame to the crossmember coming off the sides of the main frame and attaching to the front of the receiver tube BEFORE realizing my error in that I would jack-knife and not make the 90 degree turn if I stretched the A out that far. I'll have to cut it back some and maybe make it a mid-length A if that makes any sense at all??? Won't know how far I can make it till I get the box done and get to the tongue part. I got some of my steel, but the receiver tube had been hacked on accidentally by a new-hire at the steelyard, so they're bringing in a new piece for me tomorrow. I'll have to go back and get that later. As I'm running clear though the main frame with the receiver tube, the best example of the joint I had in mind for the A-frame is in this awesome build by Mr. Lefebvre as seen here:

http://www.expeditionportal.com/forum/showthread.php?t=24436&page=2

I think it's maybe mid way down the page where the receiver goes through the rectangle tube. I had the same idea in mind, then saw it done here in his awesome build and thought it was an excellent idea. Looking at it in picture looks like a little more work to fit, but with MIG, shouldn't be too tough to weld up. Should be a hair easier than he had it with TIG as that's just tough on it's own measure. Anyway, thinking of breaking the 90, then stretching the A as far out as I can get it before binding, if that makes any sense. Not sure what kind of length that's going to allow for when it's all said and done.

Another thing I guess I should mention is that I've seen it posted a few times that the "magic number" seems to be to match your wheelbase to the distance of the hitch point and the axle hub center. My 5x10 is almost this exact distance already and tows great so I'll shoot for this same measurement with this build. One other thing is my box size will be 4x6, but my swingout on my tire carrier is nearly 50" and I want to fully open the gate with the trailer strait back so I'm pushing the trailer back a little further, extending the tongue a bit longer to accomplish both tasks-gate clearance and "magic number" wheelbase/axle hub measurements-if that makes any sense. Sound logical?

Thanks again for the thoughts and advice!

Best of Luck,

Mike