trailer build steel question

[Brankulo]

so i have to change the tracks from my original plan. NT 5x8 trailer is on backorder and i also just learned that even if it wasnt, i would have to take a trip from Denver to Omaha to pick it up or pay another 4k for shipping.
so my next plan is to build one myself. i took welding class and my neighbor has fluxcore welder that i will be using. the welder says max thickness is 3/16" for steel.
my plan is to use NT design as a base and add center pipe to extend the tongue.
will 12ga or 1/8" thickness for or all the tubing except center one sufficient? i would do 3/16" for center one.
seems like 1/4" would be overkill. not intend to do any heavy off roading, just highway and some mild dirt roads.

thanks

[Squigie]

I understand wanting to make the center 3/16", but it is overkill unless your build will suffer bloat and end up heavy.
You really shouldn't need anything over 1/8", except as sandwich plates or crush tubes (where through-bolting).

I don't recall who it was, but someone posted a chart a few years ago, showing ideal dimensions and thicknesses for various parts of a specific frame design.
2x4", 0.090-0.093" wall rectangular tubing for the longitudinal supports and 0.060" cross-bracing was lighter and stronger than 1/8" (or 0.120") wall 2x2" square tube.
*assuming proper welds.

The amateur's approach to not knowing is to just go thicker with the material and pour weld wire/rod into it until they feel good about their, "that ain't goin' nowhere."
But we tend to do so with bad designs that don't end up stronger, just heavier.

[Hubert]

There is a tongue strength thread here: viewtopic.php?f=35&t=56880. The links in the thread no longer work, but you can find an archived version on the wayback machine: https://web.archive.org/web/20160530091 ... tear84.htm

There is an excel spreadsheet on the page that allows you to calculate strength for different cross sections and thicknesses. An 11ga 2" square section should be sufficient for any reasonable tongue length unless you put brakes on the trailer.

[Brankulo]

ah, that is very helpful. now is there a good way to approximate the weight of the actual cabin and trailer? is the weight considered just the build weight or build plus cabin? and once i know my weight, any way how to figure out proper tongue weight in relation to position of the axle? lots of questions but unfortunately , most of the links are broken on the forum.

[Hubert]

ah, that is very helpful. now is there a good way to approximate the weight of the actual cabin and trailer? is the weight considered just the build weight or build plus cabin? and once i know my weight, any way how to figure out proper tongue weight in relation to position of the axle? lots of questions but unfortunately , most of the links are broken on the forum.

There is some old info here: viewtopic.php?f=38&t=68446. You can dig up the links on the wayback machine and there are some spreadsheets that might be helpful. The basic math behind it is easy, getting all the data seems like a bit of an effort though.

[KCStudly]

Consider your ability to weld thinner materials well, without burning through. 11ga or 1/8 inch is easier for a beginner.

Also, consider using 3/16 for the 1st crossmember. Other than the tongue, this will be the most highly stressed member (for a 3-member tongue, 1/8 should be plenty, but if doing a 2-pc A-frame I would also recommend 3/16 here).

Don't weld along the front or back of the front xmbr where the tongue parts cross it, only weld along the tongue members from front to back under the 1st xmbr. This helps avoid stress cracks there, especially in thinner material.

[tony.latham]

any way how to figure out proper tongue weight in relation to position of the axle?

Locate the axle at the 60/40 point on the chassis frame (don't include the tongue), and it'll tow like a dream.



Tony

[Brankulo]

thanks all for responses. super helpful and about to get started on the build.
i also wander if i need to put brakes on the trailer. ideally, i probably would, but my tow vehicle is q5 that came without tow package. i did install hitch and basic wiring but to get true towing wiring installed i would be looking at outrageous fees from the dealer. so i am curious, how necessary is to have brakes for small trailer like these square drops are. what are your typical trailer weight for 5x8 builds? at what weight would you consider adding brakes to the trailer?
thanks

[tony.latham]

i also wander if i need to put brakes on the trailer.

Unless you're pulling with a 3/4 ton pickup, I suggest it's always a good idea. 99% of the time, they are not needed, but there's that one time. The time you need to dynamite the breaks and 1300 pounds of mass is pushing behind you.

Tony

[Brankulo]

i agree its a good idea for a peace of mind. i can always build with brakes and then add appropriate wiring to the car some time later. i assume using trailer with brakes without actually having the breaks hooked up is not an issue, right?

[tony.latham]

i assume using trailer with brakes without actually having the breaks hooked up is not an issue, right?

Yes, no problemo.

Tony

[gudmund]

in 2018, I bought a different PU along with my second teardrop which came with trailer brakes. For the first year I towed it without any brake system hooked-up which worked fine - being the PU's brakes worked good - trailer weight was under 1400lb(at the time) During that year, I did have a few people tell me that there -could- be a legal issue down the road "if I ever ended up being in a accident" and it was found out that I had trailer brakes -but- they were never hooked up.... ??don't know if there was any truth to that, but?? I did later that year buy and install a brake controller that mounts on the trailer itself = wasn't very cheap = but worked "GREAT".... along with it being so much easier to install and wire in. (after seeing how 'little' under-dash room there was - along with the wiring maze I said 'no way'... = ended up just needing a single power lead-wire run directly from the battery to the 7-pin connector at the rear of the PU. Now it's 4/5 years later with a 'NEW PU' which came with the 'whole' towing package option completely installed along "with" a brake controller factory mounted in the dash...... = nice.....
but now for the "complicated" question??? which 'set-up' do I use? after spending about $300 for the one I already have (which now today costs over $400+ to buy one) and "love" or use the new one that came with the new PU??? After doing my research on each controller set-up - reading the owner's Manuel and talking to the brake controller maker = could leave everything as is and have the choice of using 'either'..... and yes = test drive proved this out = both set-up's worked just fine. Ended up deciding on the factory installed set-up being the 'claims' of it to being able to work with the anti-skid vehicle braking system along with the controller switch being now dash mounted = thus now being 'so much' easier to access and find when needed in it's fixed location (the other was controlled by a hand held switch unit that is plugged into the dash power outlet - which sometimes when 'need-be' was not always where the 'hand' had thought it still was???......... did end up removing that whole set-up from the trailer and now will probably be selling it someday............PS today that 1400lb trailer weights in at just over 1800lbs - fully loaded with probably more lbs. to be added in the future.........

the roof rack & 3 awnings ended up adding over 100++lbs......so far ......

[KCStudly]

In Connecticut it is illegal to tow a trailer equipped with brakes using a TV that is not equipped to apply them, regardless of whether the trailer requires them (i.e. in CT you only need brakes for 3k lbs and up, but if I put brakes on my 1200 lb trailer, then I'm required to be equipped to use them). The dedicated self contained actuator or a standard actuator set up self contained on the trailer (you don't need to spend big bucks for the one that is marketed for self contained operation so long as you go to the trouble of setting it properly and don't need to change it frequently) may be exceptions that suit this law. Will you ever have a problem or get called out by a cop for not having a brake controller? Probably not, but they are reasonably priced and compared to the added cost of brakes, why wouldn't you? It's not hard decision if you ask me, and I have never once heard anybody comment, "gee, I wish I had never bothered to add brakes". It's always, "wish I had done it from the beginning, they're so much better".

[working on it]

Sorry to hijack the "trailer steel" thread, but I just had to respond to KC's post, and comment on my trailer brake situation.

In Connecticut it is illegal to tow a trailer equipped with brakes using a TV that is not equipped to apply them, regardless of whether the trailer requires them (i.e. in CT you only need brakes for 3k lbs and up, but if I put brakes on my 1200 lb trailer, then I'm required to be equipped to use them)...

Texas is more lenient (quoted from the Texas Dept. of Insurance website, and it's also on the Texas Dept. of Public Safety website)

A trailer, semitrailer, or pole trailer is not required to have brakes if:

1)its gross weight is 4,500 pounds or less; or
2)its gross weight is heavier than 4,500 pounds but not heavier than 15,000 pounds, and it is drawn at a speed of not more than 30 miles per hour.

My 4x8 squareback is heavy, at 2225 lbs, so when I upgraded to a 3500 lb axle in 2014, I added brakes. My tow vehicle, a 2004 Chevy 2500HD, has big 4-wheel disc brakes, and really didn't need any help from the trailer brakes (not even while descending an Oklahoma mountain, nor from 75 mph). However, I have a 2001 BMW X5 3.0i (a semi-mechanically-restored project car/daily driver that I want to tow the little trailer with sometime), but it only has a 4-way flat wiring connection (no brakes), as wired in by the previous owner (he's an electrical engineer, so I'm not sure how it's wired, unlike any of the ways I'd wired up others myself).

If i decide I absolutely need the 7-way wiring for my trailer brakes, I'll need to spend hundreds to either get the factory BMW wiring harness and module, or rig-up my own work-around from parts found on Etrailer and Ebay, with no guarantee of functionality. The X5 (an early generation E53 model) needs special wiring or the electronic light module (that controls all lighting) goes nuts; I'd get the previous owner, who wired it up earlier. to rig it up again, this time for trailer brakes, but he's no longer my next-door neighbor, and he's moved away, and incommunicado it seems.

So, I might just tow the 4x8 TTT without brakes hooked-up (or my 4.5x12 utility trailer that doesn't have any brakes), since the X5 has a towing capacity of 5000 lbs (if it had the 4.4l V-8, it'd be 6000 lbs), and pretty large 4-wheel disc brakes.

Specs, my X5 compared to my '04 2500 HD:

2001 BMW X5 E53 3.0i
• Maximum Towing Capacity (lbs) 5,000
• Gross Vehicle Weight Rating (GVWR) (lbs) 6,005
• Curb Weight (lbs) 4,519
• Payload Capacity (lbs) 1,486
• Horsepower (hp) 225
• Torque (lb-ft) 214
• Axle Ratio 4.10

2004 Chevy 2500HD 6.0l
• Maximum Towing Capacity (lbs) 12,000 (increased by adding booster springs to 13,000+)
• Gross Vehicle Weight Rating (GVWR) (lbs) 9,200
• Curb Weight (lbs) 5,153
• Payload Capacity (lbs) 4,047
• Horsepower (hp) 300
• Torque (lb-ft) 360
• Axle Ratio 4.10

The 2500HD doesn't feel the trailer back there, the X5 probably will; but since I traverse mostly flatlands, It's not a great concern, and I'll only take the X5 to local spots for camping (if ever), because the 2500HD's bed has been outfitted with more "camping-specific" gear, I'd need for longer trips.