Torsion Axle Questions

[Bubba & Thelma]

I am new to teardrops and this forum. I am now in the process of trying to find a direction in how I am going to proceed. I have looked at many ideas form others in the "Hall of fame" and am intrigued by the frameless construction on some. It looks like some really like the Torsion axle. What are people's experience with them? Good? fair? Bad?. Is a 2000 lb axle listed in Northern Hydraulics adequate for 6 x 12 Teardrops or am I undersizing it? What is a "torsion box" I hear described in the discussion of frameless construction?

[teardrop_focus]

First of all, Welcome to T&TTT!

The benefits of a rubber torsion axle are not only light weight, but perhaps more importantly the fact that the rubber acts not only as a spring but also a damper, or, a shock absorber.

What is a "torsion box" I hear described in the discussion of frameless construction?

A link to any posts or thread where this is discussed would help our discussion.




Simply, though, a trailer box built only of quality plywood where the joints are both glued, clamped then screwed together with various bulkheads, shelves or cabinetry becomes something known structurally as a "monocoque", resisting flex in both torsion and beam. It is very, very strong and although I'm not sure exactly, it might be lighter in weight compared to a similar structure built with other framework. Again, I don't know for sure...

As for the trailer chassis, however, it is peace of mind to have the trailer chassis tongue/hitch connected to the trailer axle by means of steel angle or steel tubing.

Here's a simple design for a lightweight chassis, courtesy forum user and engineering advisor Andrew/angib:

http://www.angib.pwp.blueyonder.co.uk/t ... 00.htm#New



His teardrop and small travel trailer design library can be seen here:

http://www.angib.pwp.blueyonder.co.uk/t ... tear00.htm

Anyway, I hope that's enough for you to go on... to continue your plan for a unique, small trailer.

[AZSpyder]

I picked up Northern's 2000 pound pair. My trailer isn't complete so I don't know how well they will actually work yet.

I never figured out if you would go by the trailer weight going down the road or possibly sitting at the camp ground with lots of people in it. Whatever the correct choice was the 1000 pound pair was to close to the expected empty weight.

One thing they don't talk about in the listing is the axles are about 45 degrees below the torsion housing. If you just bolt them up the the bottom of the trailer frame your axles end up about 6 inches below the frame. In my case that was too high. I bolted them to a couple of angles and welded up some brackets so I could mount the housing at an angle and lower it to what worked for my frame and wheel combo.

There was a local shop and one place I found on line that would build me a torsion axle the weight and hight I needed for about $250 but I also would have had to buy new hubs. The Northern units took the hubs of a leaf spring suspension I was removing.

I can tell already the ride is going to be very nice. So far the frame is about 200 pounds and already the suspension will move a little bit. I couldn't get the leaf springs to move at all jumping up and down on the frame but they were quite rusty.

Jerry

[kennyrayandersen]

a 2000# axle is perhaps too robust and that's why you aren't seeing any deflection. If you build it pretty stout and start hitting 12oo lbs or something then it will ride better and you should see more vertical displacement.

The axle should be rated for the going-down-the-road weight.

[madjack]

a 2000# axle is perhaps too robust and that's why you aren't seeing any deflection. If you build it pretty stout and start hitting 12oo lbs or something then it will ride better and you should see more vertical displacement.

The axle should be rated for the going-down-the-road weight.

...that is one opinion...I spec a 1500# axle for a 1200#(loaded) trailer with torsion axles...this over spec, helps with the longevity of the axle and is especially true of a suspension which is under a constant load such as a TD...it is not as critical with a torsion axle as with a spring hung axle which should be ordered at 50% over desired weight carrying ability...IE, a 1200#(loaded) tear should have an 1800# rating for a spring hung axle.......
madjack

p.s. loaded weight does not include the weight of the axle/wheel/tire combo for a spring hung axle or just wheel/tire combo for a torsion axle as that weight is "unsprung"........MJ

[kennyrayandersen]

...that is one opinion...I spec a 1500# axle for a 1200#(loaded) trailer with torsion axles...this over spec, helps with the longevity of the axle and is especially true of a suspension which is under a constant load such as a TD...it is not as critical with a torsion axle as with a spring hung axle which should be ordered at 50% over desired weight carrying ability...IE, a 1200#(loaded) tear should have an 1800# rating for a spring hung axle.......
madjack

p.s. loaded weight does not include the weight of the axle/wheel/tire combo for a spring hung axle or just wheel/tire combo for a torsion axle as that weight is "unsprung"........MJ

Maybe that's not so much over-spec-ed? Me thinks if you start using a 2000 pound rated axle on a 1000 pound trailer (full-up), the suspension isn't going to give so much and it kind of defeats the purpose of dmoothing out the ride and suckin' up the bumps.

[madjack]

...that is one opinion...I spec a 1500# axle for a 1200#(loaded) trailer with torsion axles...this over spec, helps with the longevity of the axle and is especially true of a suspension which is under a constant load such as a TD...it is not as critical with a torsion axle as with a spring hung axle which should be ordered at 50% over desired weight carrying ability...IE, a 1200#(loaded) tear should have an 1800# rating for a spring hung axle.......
madjack

p.s. loaded weight does not include the weight of the axle/wheel/tire combo for a spring hung axle or just wheel/tire combo for a torsion axle as that weight is "unsprung"........MJ

Maybe that's not so much over-spec-ed? Me thinks if you start using a 2000 pound rated axle on a 1000 pound trailer (full-up), the suspension isn't going to give so much and it kind of defeats the purpose of dmoothing out the ride and suckin' up the bumps.

...1000# trailer with a 2000# axle would be 100% overspec and would be way too much...it would tend to beat its self apart...keep in mind, the original question was about a 6x12, which would fall out on the heavier side of that 1000# mark.......
madjack

p.s. If I were to buy a Reliable brand axle from Northern, I would also buy a replacement set of bearings to have on hand for when they go byebye...would do the same with any other cheap or Chinese built units..............MJ

[AZSpyder]

a 2000# axle is perhaps too robust and that's why you aren't seeing any deflection. If you build it pretty stout and start hitting 12oo lbs or something then it will ride better and you should see more vertical displacement.

The axle should be rated for the going-down-the-road weight.

I don't know how you could tell the suspension that didn't move was 2000 pound but could be. I don't have any idea what it is or who put it on but it shouldn't be a surprised that the leaf springs didn't move when the trailer had the interior removed. I also think the rust may have had something to do with it. Of corse I did already state that the 2000 torsion did move.

I figure the trailer all up and loaded should come out at or above 1000 pounds. I couldn't see selecting 1000 pound suspension if it could be more then that. Even if I knew it was going to stay a bit under I still would have gotten the 2000 pound since I don't believe in running anything at 100%. 2000 pound was the next available size for the Northern torsion suspension. Looks like a good set up and they do start to move with just the weight of the frame. As discussed elsewhere on this forum it looks like the rubber will give a nice ride.

Jerry

[dwgriff1]

I wanted my tear to be low and the torsion axle was the best answer. I agree with the other advantages that have been given.

The axle I ordered had a 800 pound rating. My tear weighs a bit less than 600. It has worked great, and I have pulled it a lot of miles, over some of the worst words around.

Next build I would consider stub axles. Getting the absolute right axle width for the width of the trailer, the wheel offset and so on can be tricky. On this site I found a trailer some one had built the same width that I planned for mine, and ordered an axle to match those specs.

But, I still had some clearance issues.

dave

[Bubba & Thelma]

Dave & All,
Thanks for your thoughts and input. It was Daves TD that I saw in the Hall of Fame that intrigued me. While I like the idea of compact & convenient, minimalist is not our goal. For my wife to even consider the idea of a tear, It has to have the bells & whistles ie... comforts like AC, hot water, bathroom, TV etc. I am also a BIG guy, 6'2" 350+ lbs. I do not know much, but from what I have read on this forum, I cant believe I will be able to come in much under 1000-1200 lbs dry, even if I use a frameless design using "torsion box" design construction. Am I out of touch with reality?

As far as bath is concerned, I was thinking about a torsion box w/castors, with a black water tank inside it, A "drop on" toilet that fits on top, and a shower base on opposite end. All protected w/ Shower curtain walls. This complete unit would drop from under TD rear end by lift crank.

Have I had too many "G & T's"?