Jeepers off-road trailer build

[jeeper]

I've talked about building a trailer for our RTT for a while. The time is here! I think I've got it pretty well designed and planned out already. But I have no real world off-road trailering experience, and have a few questions to start:

My frame size is going to be 4x8. Is 8' too long? Our tent is just a couple inches shy of 8', and I would really like to not have the tent hanging over. I do not foresee the trailer doing anything extreme at all, as it will still be towed by my Colorado or F350, neither of which are rated for much more than exploring. I have a 10' flatbed that I haul our dirt bikes on, and have been into some fairly rough situation with it, and felt it did fine. I imagine 8' would be fine also.. Thought?

Tongue length: It seems like off-road trailers are often built with longer tongues. Is there a special reason? I imagine to keep the trailer away form the vehicle during articulation? How long should it be?

This should be a fun build for me. Unfortunately the trailer does not yet have the full support of the other majority stake holder in the family, so I have to embezzle funds for the build.. So it might go a little slower than it should. We have got 3 trips planned starting in late summer that were intended for the RTT, so I hope to have it finished by the end of August. My amount of free time, and ability to steal funds for the build will probably coincide well for that time frame.

 

[rholbrook]

Subscribed because I have been running this around through my head too.

 

[I Lean]

Subscribing.

I made the tongue on mine as short as possible, while still allowing it to jacknife 90 degrees.

 

[jeeper]

I made the tongue on mine as short as possible, while still allowing it to jacknife 90 degrees.

This was my idea as well. I think my ideal camp 'set up' situation will be with the truck and trailer at jack knife, with the RTT opening into the middle.

 

[nnnnnate]

I did the same with my tongue. If you decided it ended up being too long its pretty easy to cut it back. I could (and probably should) trim mine down a few inches but its fine and hasn't hurt anything. As far as length, my box is 44" wide and a little over 6' long but I do have a space in front of the box for water jugs and gas cans that is probably at least 2'. My trailer is no beauty queen and I'm obviously a total hack but I've pulled it through Black Dragon Canyon twice without any trouble, with a normal 2" ball hitch.

I'm excited to see what you come up with.

 

[I Lean]

Incidentally, I have a pretty good length of 2.5" square 3/16" wall tube that I used for part of my trailer. If your plans include that size, hit me up before you buy a piece.

 

[jeeper]

Incidentally, I have a pretty good length of 2.5" square 3/16" wall tube that I used for part of my trailer. If your plans include that size, hit me up before you buy a piece.

I includes about 7-8' of it..

 

[I Lean]

I'll look tonight and let you know how big my remnant is.

 

[dutchman]

Subscribed. Always liked the idea of building an off-road trailer.

 

[Tonkaman]

I remember reading about proper tongue length somewhere, maybe here? There is a formula to make sure the trailer tracks as close to the trucks tires as possible.

I'd also recommend Timbren type axles to help with flex and vibration.

 

[jeeper]

I remember reading about proper tongue length somewhere, maybe here? There is a formula to make sure the trailer tracks as close to the trucks tires as possible.

I'd also recommend Timbren type axles to help with flex and vibration.

I'd love to do the Timbren axles.. but I am way to cheap to spend the money on them. If for some reason we decide that an offroad trailer becomes our favorite way to camp, I can see that trailer 2.0 could get more designing and better parts.. but for now, I think I will stay a little cheaper. I do hope to get some longer springs to help with ride quality on the trailer.


Edit: On second thought.. I know a guy selling the dexter torsion axles.. I wonder if those could be cut to length.. I'll look into it. That would at least be better than leaf springs

Edit Edit: 2,000lb torsion axle being picked up tomorrow.

 

[Tonkaman]

Why 8' long? What do you need to haul?

Edit: I re-read the first post. I get it now

 

[I Lean]

You could shorten it pretty easily, similar to how nnnnnate widened his axle.

 

[jeeper]

Axle picked up. I sold a couple things today and swindled my first few Benjamins.. So I've got about $500 to get this started!

 

[nnnnnate]

After Carl said he had some square I remembered I had a piece of 2.5x2.5 and measured it. Its 6'6" long and is 10 gauge. I doubt I'll use or need it for anything. Let me know it thats of any interest to you.

 

[Anchor_Mtn]

Tongue length: It seems like off-road trailers are often built with longer tongues. Is there a special reason? I imagine to keep the trailer away form the vehicle during articulation? How long should it be?

Ideally, your track width should be the same width as your vehicle and the distance from your ball/coupler to your trailer axle should be the same as the wheelbase of your towing vehicle to give you the best offroad tracking. Also you should be shooting for 10-15% of the total dry weight of the trailer for your tongue weight. If you need any parts/advise, Im happy to help along the way. Enjoy your build!!

 

[Tonkaman]

Ideally, your track width should be the same width as your vehicle and the distance from your ball/coupler to your trailer axle should be the same as the wheelbase of your towing vehicle to give you the best offroad tracking. Also you should be shooting for 10-15% of the total dry weight of the trailer for your tongue weight. If you need any parts/advise, Im happy to help along the way. Enjoy your build!!

Ahh yeah that makes sense.

I'm curious how do you design the trailer for 10-15% tongue weight? I understand it has to do with weight distribution in the box, and also box position to the axle. I don't understand how to design it so that those numbers just work

 

[cruiseroutfit]

Ahh yeah that makes sense.

I'm curious how do you design the trailer for 10-15% tongue weight? I understand it has to do with weight distribution in the box, and also box position to the axle. I don't understand how to design it so that those numbers just work

Free Body Diagram

 

[Gravy]

Free Body Diagram

View attachment 109005

UofU MechE FTW.

 

[jeeper]

I plan to have a receiver on the rear that can receive my moto hauler, which will make a big difference on tongue weight depending on if the bike is or isn't with me. I think I decided this weekend that there will almost always be a bike o the carrier, so I am going to plan on that additional weight and also change my tail lights to assume the bike is there.

On thing I needed to figure out before this while build go started was whether or not the annex would actually give us enough room for the whole family. I also needed to see how high the tent needed to be for the annex to fit right. So for the first time ever, the annex was pulled from the bag. It made a ton of room, and made my wife see the vision and become excited about the trailer build. That's a big win.

The kids were being their usually rowdy selves as we were setting this up, and we had a short Conversation about selling this tent and buying two small ones so the kids could sleep separate. But after a short deliberation we decided to keep this.



Her is how she sits tonight.