5X10 chassis build (FIRST POST)

[davkrat]

Hello this is my first post. I have been reading like crazy about teardrops the last few weeks. I really want to build a 5X10 Benroy style teardrop. My brother and I are both 6'2" and 250+lbs. so we want as much sleeping room as possible. My wife and I could probably get by with something smaller but I hate feeling cramped. I would like to build a frame out of 2" square tubing and use a 2,000lbs. leaf sprung axle. I want to use the same wheels and 31" tires that I have on my Jeep CJ7 for use off road or at least on poorly maintained dirt roads. I was thinking of putting 2" square tube cross members on 24" centers so I'll end up with 10" side rails and 6 54" cross members with a 2"X3" tongue extending to the second cross member. I want to build it strong for non-pavement use. My question is... is this all overkill? Will the trailer being taller pose a problem? I do a lot of bad road driving and want some added clearance to get into hunting/fishing areas. Thanks for the info, this is all very exciting and overwhelming.

[Shadow Catcher]

Why square, think of forces, rectangular gives more strength vertically and you should be able to go with smaller lighter gauge metal. Or round.

[davkrat]

I keep hearing about chassis being overbuilt, I think perhaps even 2"X2" .125" tubing may be overkill. I think that rectangular tubing would be even worse. I wanted a 2" wide flat top to the chassis members to facilitate fastening the floor to the frame using self tapping deck screws. perhaps the interior crossmembers could be 2"X2" Angle and use the square only for the perimeter? I want this trailer to be strong enough not to worry about dragging it down bumpy washboard roads and across small streams/washouts. I don't trust a HF trailer for those uses. I also want if to stay relatively lightweight. I just found the offroad section of this forum and started looking around there, seems like 2"X2" is pretty standard for offroad frames.

[Uncle Chan]

Davkrat,

I'm in the process of ordering built a trailer with much the same dimensions as yours. The only difference is that I'll be using a 3500lb axle and 750lb springs on each side. Mine will be for off-road too, using the same wheels and such as my F150 and FSB (full size bronco). The only real question I'm having is 2x3 rectangular or 2x2 square? Tough choice.

[davkrat]

sounds like I should definately go with square tubing for the entire chassis including crossmembers. I think I will only use the 2"X3" for the tongue, maybe with some 2" angle to brace the tongue and provide mounting locations for a tongue box. I've started using Sketchup here are a few examples:







Nothing fancy, it's sure fun to play around with designs. I am also thinking of making the lower bulkhead/divider between the galley and the sleeping area removeable. That way I could slide sheets of plywood and other large items in through the hatch. That way I would have a somewhat useable utility trailer without having to dismantle the "box" from the "frame". I just want a simple galley to store cooking gear and then put a cooler and water containers under the counter.

[aggie79]

Unless you are planning to use thin plywood, say 1/2"for your floor, the crossmembers are overkill. With a leaf spring setup it is probably good to have one in the area of the hangers. I two interior crossmembers but even these are not necessary from a structural standpoint since I used an insulated, torsion box, style floor. (I did use a torsion axle which functions like a crossmember.)

[doctor phreak]

Unless you are planning to use thin plywood, say 1/2"for your floor, the crossmembers are overkill. With a leaf spring setup it is probably good to have one in the area of the hangers. I two interior crossmembers but even these are not necessary from a structural standpoint since I used an insulated, torsion box, style floor. (I did use a torsion axle which functions like a crossmember.)

hey aggie i like how you timed your reply to the question....sep (9) 9, 2009 @ 9:09

d yours setup dont sound that bad in fact i think my is more overkilled than yours....i am using 1/2 ply with 2 x 4 framing with 1" foam insulation than with another 1/2 ply on the bottom than all of this on a 1-3/4" x 4" c channel trailer frame...this sounds overkill to me...yours sounds alright to me.....in fact the axle i have is a 3500lb axle with out leaf springs and then i have 5 or 6 leafs springs underneath the axle so i am guessing the setup is about 4500lbs...and just to let you know i am using a boat trailer for my TD

[greekspeedoman]

davkrat,

My build was a tube frame (2") with 1" x 2" c channel cross members. I have used it off road quite a bit with no problems. Some may say it is overkill but I'd rather that then to break my frame in the middle of the wilderness. You can see my design Here: http://jpodbuild.wordpress.com/chassis/

The only thing I plan to add to it is a place to mount a propane tank & some monroe shocks to tame the springs.

I have a friend who copied my frame design & it is working well for him too. You can see his build at: http://www.melwade.com/teardrop/chassis

[davkrat]

Thanks for the replies, I have seen the JPOD build and that is exactly what I am going for. I did some math and the difference between the various tubes/angle is only about 50 pounds for a 5'X10' which has about 50' of tubing, the tongue will be 2"X3" regardless. I am thinking that maybe 1"X2" might be the way to go, probably have similar vertical strength as 2"X2" but about a 30% reduction in weight. I think that if I don't add all the bells and whistles (sinks, grey water, entertainment center) Ishould be able to keep the weight down. I've been burning up a ton of flux core practicing for my frame hopefully in the next month I'll be able to get started. Thanks for the info!

[emiller]

Check out Larry's and Diane's build sounds like the same chassis your talking about http://www.outbackteardrop.com/

[greekspeedoman]

Actually, the outback teardrop is similar to the jpod but not the same. Theirs is even burlier than mine. They used 2" tube steel everywhere instead of the c channel & they have a center tube down the whole frame. I'm sure theirs will never fall apart. But mine hasn't either & it is lighter.

A 1" x 2" could save you some weight & would probably be just fine for most needs. Keep us posted on your progress. If I build again, I may use your specs. I'm glad the jpodbuild has been helpful.

[davkrat]

So here are the calculations for the various forms of steel. I got the information from the PDM Steel catalog: http://www.pdmsteel.com/PDF/pdm_cat2006c.pdf They are located near me in Stockton and I will probably get my steel from them. Here are the weights:

2"X2" .120 angle - 1.652 lbs./ft.

2"X1" .120 rect. - 2.254 lbs./ft.

2"X2" .120 square - 2.940 lbs./ft.

2"X3" .120 rect. - 3.890 lbs./ft.

For a 5'X10' frame with a total of six cross members (1 front, 1 back and 4 on 24" centers) there is 50' linear feet of tubing. The three options I have had in mind are an all square tube frame, a square perimeter with angle cross and an all 2"X1" frame. You'll see that the differences in weight are pretty slight.

All square: 50' X 2.940 = 147 lbs. total

Square perimeter 30' X 2.940 = 88.2 lbs
angle cross members: 20' X 1.652 = 33 lbs. 121 lbs. total


2"X1" rectangle: 50' X 2.254 lbs.= 112.7 lbs. total

The tongue 8' 2"X3" : 31.1 lbs. will be the same regardless as will the axles, etc.

So of all these methods I am looking at a 35 lbs. difference in the basic frame weight. I know eventually every little bit adds up but this seems to small be that big of a deal. I do not plan on towing the trailer with a small car. I think I'll just go ahead with the 2"X2" square. If someone did want to make one completely out of angle it would only weigh in at 50' X 1.652 = 82 lbs. If you were towing only on asphalt with a compact 4 cylinder I can see how that would start to be attractive.

[oldtamiyaphile]

I do not plan on towing the trailer with a small car.

Last I checked, the CJ7 is a small car. It will handle the load no problem, but a SWB Jeep on off road tyres can become unstable when towing (especially since it's not really stable to begin with). Wheelbase is why the Unlimited versions have double the tow capacity.

I believe the CJ7 is rated the same as the TJ, 1000# unbraked. It's not hard to exceed that if you're not careful. You're already close to 200#, by the time you add 31" tyres, suspension, coupling etc, you'll be up near 400 odd. That leaves you with 600# for your body and payload.

Personally, I'm aiming for 600# with a light off road build and still fitting brakes for towing with my TJ.

[davkrat]

You mean how they made a Jeep no longer a Jeep. Sorry, I couldn't resist, I just can't stand the bigger is better thing some times, that 4 door H3 wannabe is hideous. By small car I meant a small 4 cylinder. I should have said a "mini" car. I know that wheelbase come into play as far as towing stability but I doubt I'll have any trouble pulling a TD with my Jeep, I have pulled plenty of boat trailers with it. The longer body of a 5X10 should make the tow a little more stable. For serious offroad I would deffinately be adding brakes. I'm more concerned with it surviving washboard roads, unexpected potholes and drop offs at washouts/stream crossings.