15x7' trailer design thread

[iconicflux]

I've been working on a modification to Tony's trailer design incase I have to have a trailer made in the case of my coleman frame falling through.

I was thinking I'd use a 3500 lbs axle in it although I'll *hopefully* have under 2500 lbs. (3500 is the max I could possibly tow)

Any chance y'all could help me figure out which Dexter / Flexiride torsion axle to use with it? I'll admit that I'm somewhat unsure on the axle choices and want to not make the wrong choice.

Screen Shot 2021-02-18 at 10.18.09 PM copy.png (231.05 KiB) Viewed 1740 times

Thanks

[tony.latham]

You need to move the axle back to the 60/40 point on the frame. (The spindles, not the crossbar). Otherwise, it'll be dangerous to pull.

The big mystery is how much a trailer of that size will weigh (loaded for camping). Maybe 2,000. Maybe 2,500.

The hub face is easy. 14" wider than the frame size.

Tony

[iconicflux]

I moved the axle back a few inches per what you said. I know it doesn't look like it's at 40/60 but with the tongue it is.

trailer2b.PNG (66.75 KiB) Viewed 1706 times

I'm not sure this trailer is going to work for me. I need to keep the total width to about 7'8".

Can I thin it out and add wider boxes on either side of the tires and maybe shrink the triangle some so it's easy to change it out to a swingaway tongue?

Something like this:

trailer3b.PNG (58.4 KiB) Viewed 1706 times

[John61CT]

60/40 is without considering the A-frame.

Just a guideline, the critical spec is that weight on the ball is 8-12% of the total, no more no less.

So the hub centers can be rearward of 60/40 if your battery bank, water & propane are all to the rear of it

or needs to be forward of that point if your heavyweight gear is as well.

The ideal is heavy loads are close to the axle, and of course low.

[MickinOz]

My trailer ended up at about 65/35, I think. My memory ain't what it used to be.
I landed just about spot on 10% of the total weight on the hitch. By happenstance rather than planning, my inside cabinets are pretty much centered over the axle so while the weight of any luggage will be up a little high, it won't affect the forward/rearward weight distribution much.

I always assumed I'd use the battery and the spare wheel as relocatable ballast to maintain reasonable weight distribution, and I'm looking at underbody mounting options for the spare.
If I did it again (planning to) I'd just go with 60/40. Them ol' timers knew their stuff.

[MickinOz]

Guy at work is calculating his square drop trailer right now.
He's getting very scientific with his estimations of installed weight of his materials.
Recommend it because, if you do come in under 2500 with a 3500 axle, it might be a touch hard riding.
Unless your 2500 doesn't include water, bedding camping stuff?

[iconicflux]

My plan is to actually test it once everything is built and have a welder modify it if necessary to move the wheels where they need to go so I can get the weight on the tongue to the optimal level to control sway. Figure I'll just take it into the dump's scale, record it, go back out and unhitch it by the recycling area and then go back through with just my car.

So I modified the axle placement again to this:

Screen Shot 2021-02-19 at 10.05.15 AM copy.png (173.56 KiB) Viewed 1642 times

What is meant by "hard riding"? Lots of bounce? I was figuring that extending the tongue 4-6" would help with a little bit of that and also give more clearance for turning. The reason I'm looking at possibly having the triangle shorter is because if I can put a folding hinge at about 16' then it fits in the garage far easier. I haven't figured out how to make a larger triangle tongue fold yet.

Thanks

Guy at work is calculating his square drop trailer right now.
He's getting very scientific with his estimations of installed weight of his materials.
Recommend it because, if you do come in under 2500 with a 3500 axle, it might be a touch hard riding.
Unless your 2500 doesn't include water, bedding camping stuff?

[tony.latham]

A removable tongue is easy. Hinging one? Maybe, but I think you'd be relying on the strength of the hinge pin but perhaps there's a way of doing this.

Relocating axle placement after the fact wouldn't be easy. I don't know how a guy would clamp new brackets on the frame prior to welding (and get them perfectly plumb to the coupler). I might suggest --at the minimum-- have the guy weld additional brackets at the 40/60 point while he's welding your trailer up, and mount the axle there.

Here's the issue with an axle that's too far forward:



That's why sway-induced wrecks happen.



Tony

[working on it]

A removable tongue is easy. Hinging one? Maybe, but I think you'd be relying on the strength of the hinge pin but perhaps there's a way of doing this....

* I thought of adding one to my trailer (single-beam, 3"x3"x.187" x 45" long past the front wall, 27" behind), but decided that it might not be strong enough to use with a Weight Distributing Hitch exerting force on the two joining pins. And, my trailer is quite heavy for its' size, with 260+ lbs tongue weight. Fulton says the device is made of die-cast steel, but there's no indication of how strong it is, or weight-bearing capacity.

* https://www.fultonperformance.com/products/trailer-couplers/fold-away-couplers/IcDNSpx3DOQ2iA2x!UrxsGHZeED7ZvuS

FULTON fold-away coupler.jpg (78.65 KiB) Viewed 1617 times

[MickinOz]

A removable tongue is easy. Hinging one? Maybe, but I think you'd be relying on the strength of the hinge pin but perhaps there's a way of doing this.

Relocating axle placement after the fact wouldn't be easy. I don't know how a guy would clamp new brackets on the frame prior to welding (and get them perfectly plumb to the coupler). I might suggest --at the minimum-- have the guy weld additional brackets at the 40/60 point while he's welding your trailer up, and mount the axle there.

Here's the issue with an axle that's too far forward:



That's why sway-induced wrecks happen.



Tony

We do swing away drawbars here. Just the thing for getting a long trailer in a short shed. Lot of designs - here's just one.
https://easytow.com.au/fish-sports-galv ... drawbar-2/
The other thing we do is mount the springs onto sliding brackets that then bolt to the main frame, so that the weight distribution can be adjusted.
My trailer is done like that, but with the fenders actually bolted to the teardrop, not the chassis. T move the axle would mean new mounting holes for the fenders. Not keen.
I imagine you could easily do as you suggest - build several mount points on the frame for the axle, so if the first choice of position doesn't work a new position is ready to go.

[tony.latham]

I know it doesn't look like it's at 40/60 but with the tongue it is.

The 60/40 is the frame without the tongue on a single-axle trailer. Four a double, it's with the frame.

If you getting that from my book... that was a mistake and it's been corrected.

Tony

[iconicflux]

I'm totally okay with it being a removable tongue as long as it's relatively easy to put on and off and it is strong enough to not break.

I've seen the removable tongue like you have, can you just use something like an extension piece of 2x2" x 1/4" steel to a coupler sleeve to make a longer removable tongue?

A removable tongue is easy. Hinging one? Maybe, but I think you'd be relying on the strength of the hinge pin but perhaps there's a way of doing this....

* I thought of adding one to my trailer (single-beam, 3"x3"x.187" x 45" long past the front wall, 27" behind), but decided that it might not be strong enough to use with a Weight Distributing Hitch exerting force on the two joining pins. And, my trailer is quite heavy for its' size, with 260+ lbs tongue weight. Fulton says the device is made of die-cast steel, but there's no indication of how strong it is, or weight-bearing capacity.

* https://www.fultonperformance.com/products/trailer-couplers/fold-away-couplers/IcDNSpx3DOQ2iA2x!UrxsGHZeED7ZvuS

FULTON fold-away coupler.jpg

[John61CT]

The Axle-less Timbrens are more front-rear oriented

so easy to design & pre-drill your holes

to just slide the suspension along the main chassis frame rails, relocate as needed,

can even do it out "on the road" assuming they are parallel within tight tolerances.

_______
Using too-HD a suspension with too light a load means a stiff ride, stuff gets shock-bounced around can even break stuff.

So 3500 units aren't great for a 2500# GVW.

With some of the Timbren models, you can order the next size down rubber bits to swap into the HDer unit

then if you add more weight later, just swap the original rubber back in, easy peasy.

The eTrailer.com team has a direct line into Timbren engineering to get specific details.

[saltydawg]

I'm totally okay with it being a removable tongue as long as it's relatively easy to put on and off and it is strong enough to not break.

I've seen the removable tongue like you have, can you just use something like an extension piece of 2x2" x 1/4" steel to a coupler sleeve to make a longer removable tongue?

I would not do an extension, I would do more than one tongue of different lengths. Just put in the on you want to use.

[iconicflux]

Im going to have to look back through the design because i thought the tongue came as a piece that's inserted into a coupler from tonys specs