Building my own trailer - need some advice

[N8TGK]

Stacked 330 gal IBC totes filled with water on a single axle trailer behind a 1/2 ton truck.


What could go wrong!!

Yeah water... If something does happen I can dump it out to reduce weight.

9000lb axle, 8000lbs of payload on the rare occasion I'm actually maxed...

half ton truck with 9500lbs towing capacity, actually towing 8000lbs...

I'm sorry but I just don't see the problem here, if someone would like to explain it that'd be great. A whole lotta people saying it's a bad idea, but not specifically why. All the numbers seem to add up to me...

 

[rabler]

Why mess with 2 axles instead of 1 big / heavy one? I'm never gonna have more than 8000lbs counting the weight of the trailer itself so why would I go through the added trouble of making 2 axles play nice together when I can buy 1 9000lb axle and call it a day?

Check the cost and size of appropriate tires. Not sure you can even find something in a reasonable size that will run without going dually on a 9k axle. Also note that with two tires per side, a flat is much more manageable. With dually, you now have width considerations, wider fenders, etc.

I've towed large/overweight loads long distances. Hi pucker factor, and there are undoubtably safety issues. Big question in my mind would be is this for local use or long haul?

 

[N8TGK]

Check the cost and size of appropriate tires. Not sure you can even find something in a reasonable size that will run without going dually on a 9k axle. Also note that with two tires per side, a flat is much more manageable. With dually, you now have width considerations, wider fenders, etc.

I've towed large/overweight loads long distances. Hi pucker factor, and there are undoubtably safety issues. Big question in my mind would be is this for local use or long haul?

Local only, never on any highways, gonna spend alot of its time on dirt roads or private roads. Rural area so if something were to happen there's no problem with dumping my water on the side of the road to reduce weight in an emergency.

Actually yeah, dually might be a good compromise. Pain in the ass if I get a flat, but at least I wouldn't need to buy and build around a second axle... I'm gonna make the deck 4' maybe 4.5' max so the extra width fenders shouldn't be a problem.

And realistically I'll very rarely need more than 330 gallons so I'll probably keep the top tank empty most of the time (although I'm definitely concerned about the center of gravity with 2 stacked ibc totes full of water) and only fill it when I know in advance I'll need it. So I won't be at my max weight very often at all.

 

[rabler]

Personally I'd prefer two axles over single dually. Many things like cracks in the road run across the road so with a dually both tires take the impact at the same time. That's harder on the tires, and the ride. (My big trailer is a dual axle dually tires, 22k gooseneck). Keep in mind that without a dually pickup, dually axles extend wider than your truck. That's just asking for problems.

 

[Ultradog MN]

Last year I bought a 5x8 utility trailer and upgraded the heck out of it while teaching myself how to weld. Well now I enjoyed that so much I want to try something bigger.
I plan on building a pressure washing, hydroseeding, and fire fighting trailer unit, gonna have a skid mount hydroseeder, a big pressure washer, a water pump, and 2 ibc totes full of water.

The majority of the weight on the trailer will be about 5500lbs of water when its full (assuming 2 full 330 gallon ibc totes), and that plus all the equipment I figure to be safe that's about 7000lbs total, so I'm thinking an 8000 or 9000lb axle.

With leaf springs do I get them by the weight rating on the spring or on the axle? Would I get 2 8000lb springs for a trailer with a 8000lb axle, or would I get 2 4000lb springs for it? What do y'all suggest for the main frame / body of the trailer? Is C channel enough or should I go for square tubing? What thickness? I'm really new to metalworking in general and want to make sure to overbuild everything for safety since I'll be driving it on the road. If I need 3 1/4" angle iron braces I'll put 4 3/8" braces...

Is there some guide or source material I can read that will teach me how to calculate the weight a given profile needs to permanently deform? I want to learn how to pick/calculate what thickness material I need for a given project.

First of all, what are you going to pull the trailer with?
No sense building a trailer that has a max rating higher than the rating of your tow vehicle.
Secondly, at 7000+ you need a tandem axle trailer. Period
Trailer axles generally come in different weight ratings. Most tandem axle car haulers will use 3500 lb or 7000 lb rated axles.
Tandem 3500 lb axles will give you a 7000 capacity trailer.
7000 lb axles will give you a 14000 lb tandem trailer.
But remember, those weights are for Combined weight of the trailer plus the load.
The cost of materials for a 14K trailer will be more than TWICE the cost of a 7K trailer.
Think about it: you will need the axles, brake kits, springs, shackles, walking beams, coupler (2" for 7k, 2 5/16" for 14k)
And check your local laws to see if you need the breakaway kit. You will need the brake controller in your tow vehicle. Plus lights, pigtail, wiring, safety chains, etc.
I have a 14k 16' car hauler. It requires load range E rims and tires (8 bolt).
It weighs about a ton. Empty.
That is a lot of steel to buy.
In today's hyper litigious world are your welding skills up to that task? Can you engineer your trailer with appropriate materials so the trailer componants are sized properly? Not too light so it breakes somewhere and not too heavy so you are hauling around unnecessary weight?
I get the love of a project - especially the love of a good welding project as I'm an old stick man myself that could lay in some pretty good 7018 welds in my day.
But now, since my skills aren't what they were, with the prices of steel and all the componants, and the laws, and the blood sucking attorneys, I think I would look for a decent used trailer if I needed one and pass all the gotchas on to someone else.

 

[den-den]

I recommend you check the regulations more closely (both federal and state) if you might ever get on an interstate hwy. Regardless of regulations, I would not want to tow that without trailer brakes.

 

[N8TGK]

First of all, what are you going to pull the trailer with?
No sense building a trailer that has a max rating higher than the rating of your tow vehicle.
Secondly, at 7000+ you need a tandem axle trailer. Period
Trailer axles generally come in different weight ratings. Most tandem axle car haulers will use 3500 lb or 7000 lb rated axles.
Tandem 3500 lb axles will give you a 7000 capacity trailer.
7000 lb axles will give you a 14000 lb tandem trailer.
But remember, those weights are for Combined weight of the trailer plus the load.
The cost of materials for a 14K trailer will be more than TWICE the cost of a 7K trailer.
Think about it: you will need the axles, brake kits, springs, shackles, walking beams, coupler (2" for 7k, 2 5/16" for 14k)
And check your local laws to see if you need the breakaway kit. You will need the brake controller in your tow vehicle. Plus lights, pigtail, wiring, safety chains, etc.
I have a 14k 16' car hauler. It requires load range E rims and tires (8 bolt).
It weighs about a ton. Empty.
That is a lot of steel to buy.
In today's hyper litigious world are your welding skills up to that task? Can you engineer your trailer with appropriate materials so the trailer componants are sized properly? Not too light so it breakes somewhere and not too heavy so you are hauling around unnecessary weight?
I get the love of a project - especially the love of a good welding project as I'm an old stick man myself that could lay in some pretty good 7018 welds in my day.
But now, since my skills aren't what they were, with the prices of steel and all the componants, and the laws, and the blood sucking attorneys, I think I would look for a decent used trailer if I needed one and pass all the gotchas on to someone else.

I'd tow it with a GMC Sierra 1500 with a 9500lb towing capacity. With the weight of the trailer and everything on it I estimate it'll never be more than 8000lbs, and since I plan on keeping one of the totes empty except for when I need it it'll rarely even be that.

I have the brake controller already, I'm familiar with towing heavy trailers from renting a dump trailer several times and that's way wider than the truck is and I've never had a problem.
If the trailer weighs over 1500lbs empty then it needs a breakaway cable, but that's cheap and easy to do. I'm already familiar with trailer wiring and whatnot and not worried about it, I wired up my little utility trailer with a 7 blade connector and backup lights with a switch so they double as auxillary work lights.

Why do I need tandem axle if I have a 9000lb axle with 8000lbs of weight towed by a vehicle with a capacity of 9500lbs. All those numbers seem to line up. Why would I pay so much more for materials to go with 2 say 4500lb axles instead of 1 9000lb one?
I get that that might be the case given how many people have told me that I need multiple axles, but purely based on the numbers I don't understand why when I can just buy a 9000lb axle... And nobody has said why, aside from possibly safety or redundancy.
How exactly is there a problem with 1 9000lb axle with electric brakes?

I live in a very rural area, it'll always be within a few miles of home, never on the highway, and mostly on private roads and dirt roads in the middle of nowhere. If something were to happen I can drain water to reduce weight.

yeah it is alot of steel, but I got some stuff I can repurpose.
No my welding skills aren't up to the task I'm very new to welding and taught myself. And nah I can't engineer it well either but that's why I said in my post that I want to know what size components from so I can overbuild it. "If I need 3 1/4" braces I'll put 4 3/8" braces"

I don't see anyone making a 4x10 utility trailer with a 9000lb capacity, and buying one new is way outside my budget anyway. That's basically the realm of heavy equipment trailers which I don't need.

I know very well about the cost, which is why I'm trying to keep it to one axle.

 

[N8TGK]

I recommend you check the regulations more closely (both federal and state) if you might ever get on an interstate hwy. Regardless of regulations, I would not want to tow that without trailer brakes.

Idk where y'all are getting no brakes from, I said a few times now that I'm going to use electric brakes whether it's required or not (it is for trailers with an empty weight above 1500lbs )

And it'll exclusively operate in a rural area with never being on any major highway. 2 lane rural roads, dirt roads, and private roads only.

 

[N8TGK]

Personally I'd prefer two axles over single dually. Many things like cracks in the road run across the road so with a dually both tires take the impact at the same time. That's harder on the tires, and the ride. (My big trailer is a dual axle dually tires, 22k gooseneck). Keep in mind that without a dually pickup, dually axles extend wider than your truck. That's just asking for problems.

Fair enough, but it's just so much extra initial cost and maintenance for the second axle. And I'm not too worried about the width, I'm familiar with towing a wide dump trailer or car hauler, both of which are way wider than the truck. And my hypothetical trailer even with dually still probably wouldn't be wider than the truck, and definitely narrower than the dump / car hauler trailers.

 

[Ultradog MN]

I'd tow it with a GMC Sierra 1500 with a 9500lb towing capacity. With the weight of the trailer and everything on it I estimate it'll never be more than 8000lbs, and since I plan on keeping one of the totes empty except for when I need it it'll rarely even be that.

I have the brake controller already, I'm familiar with towing heavy trailers from renting a dump trailer several times and that's way wider than the truck is and I've never had a problem.
If the trailer weighs over 1500lbs empty then it needs a breakaway cable, but that's cheap and easy to do. I'm already familiar with trailer wiring and whatnot and not worried about it, I wired up my little utility trailer with a 7 blade connector and backup lights with a switch so they double as auxillary work lights.

Why do I need tandem axle if I have a 9000lb axle with 8000lbs of weight towed by a vehicle with a capacity of 9500lbs. All those numbers seem to line up. Why would I pay so much more for materials to go with 2 say 4500lb axles instead of 1 9000lb one?
I get that that might be the case given how many people have told me that I need multiple axles, but purely based on the numbers I don't understand why when I can just buy a 9000lb axle... And nobody has said why, aside from possibly safety or redundancy.
How exactly is there a problem with 1 9000lb axle with electric brakes?

I live in a very rural area, it'll always be within a few miles of home, never on the highway, and mostly on private roads and dirt roads in the middle of nowhere. If something were to happen I can drain water to reduce weight.

yeah it is alot of steel, but I got some stuff I can repurpose.
No my welding skills aren't up to the task I'm very new to welding and taught myself. And nah I can't engineer it well either but that's why I said in my post that I want to know what size components from so I can overbuild it. "If I need 3 1/4" braces I'll put 4 3/8" braces"

I don't see anyone making a 4x10 utility trailer with a 9000lb capacity, and buying one new is way outside my budget anyway. That's basically the realm of heavy equipment trailers which I don't need.

I know very well about the cost, which is why I'm trying to keep it to one axle.

I did a quick look around for the CVWR or GVWR for a 1500 and didn't readily find it.
There should be a sticker in your door or maybe someone here has it at their fingertips.
Your 9500 sounds about right but I'm thinking that is your GVWR not the weight you can pull.
As for the one axle vs two...
I learned the reason you want two axles when I was still playing on these things.
Seriously, you want a tandem to haul that much weight.