Weight distribution on a generator trailer

Discussion in 'Towing & Trailer Tech' started by Crawdaddy, Mar 4, 2013.

  1. Crawdaddy

    Crawdaddy Moderator Staff Member

    I heard from a friend that Harbor Freight currently has a good price on their biggest trailer. Here's a link to it: http://www.harborfreight.com/automo...-12-inch-five-lug-wheels-and-tires-94564.html . Well, I figured that this is a perfect time for me to build my generator trailer that I've been wanting to build for some time now.

    The trailer claims a weight capacity of 1720 pounds. Well, the generator weighs in the neighborhood of 1200 pounds and I have a 100 gallon diesel tank to put on the trailer too which will weight around 720 pounds, plus other miscellaneous weight of cables, ground rods, etc, for another 100 pounds. So, total weight is closer to 2000 pounds. I'd be overweight by 300 pounds, but this trailer wouldn't see a lot of hard highway miles. To stiffen things up and to provide solid mounting for the gear, I'd be adding in additional braces and bars under the deck.

    The killer for me is deciding where to put everything on the trailer. With the genset weighing 1200 and the diesel tank weighing 720, I've got to figure out how to balance this trailer so I'm not tongue or tail heavy. One thing's for sure, the weight of the generator is a known, but the tank is variable. So, my thoughts are to put the tank over the axle or slightly rear of it, and then put the generator as close to the tank as possible to try to keep tongue weight low and everything over the axle.

    Any thoughts on how to balance this thing?
  2. SurrealOne

    SurrealOne Former Member

    You may be a mechanical or structural engineer who happens to also have the fabrication skills and equipment to not only do the proper math to compute the weak points in an overload scenario, but also compensate for them. However, I am doubting this, as someone with those skills would also be able to scientifically compute/calculate/optimize load placement.

    If I were in your shoes, I would start by choosing a trailer that isn't already overloaded. You may feel the risk is low, however, on that day where you slam on your brakes to avoid a deer or kids or some other ... and hit something ... your insurance company may feel they don't need to pay for your loss or the damage you caused because you were towing an overloaded trailer.

    Is the money you save by going cheap, now, potentially worth a life and/or being poor for the rest of yours? Only you can decide that. For me, it wouldn't be worth the risk...
  3. Pikey

    Pikey Moderator Staff Member

    I agree with [MENTION=50075]SurrealOne[/MENTION] , But a bigger trailer. The weight limit may not be only based on the structure steel used to make the trailer but, the wheel hubs (or spindles) and bearings. They may not be able to handle the weight that you want to put on the trailer. Even if you disperse the weight as you want, the axle might not take the load well.
  4. Conlan Rose

    Conlan Rose Super Moderator

    If you read the owners manual for the HFT trailer it says the axle is rated a little higher, but the springs will totally compress at that weight.
  5. dsfloyd

    dsfloyd New Member

    Going to agree with what is said above so far. I can see the axles and hubs being the weak points. I have one of those trailers (a little smaller one 1090-lb-capacity-40-1-2-half-inch-x-48-inch-mini-utility-trailer-with-12-inch-four-lug-wheels-and-tires-90153) from harbor freight and I mainly just have a 65 gallon water tank making up the wieght. Looking at the two the one you are looking at has the full tube axle where mine doesnt (has a C channel and the spindle goes in about 4 inches on each side). Now the trailer works well and drives well. I even take it on some longer highway trips. The one thing I say about their trailers is to switch the tires. They are crappy chinese made and I already had one blowout. I switched the tires out for some carlisle trailer tires.
  6. Crawdaddy

    Crawdaddy Moderator Staff Member

    I've been planning on this trailer for some time now, but I haven't been able to find an affordable platform to build off of. So far the cheapest trailer I can find that will hold the claimed weight is over $700. So, I haven't done it yet. I know that's not a bad price for a trailer, but for something so small that will primarily sit, it's high. I've considered building one from scratch, but I'm sure it'll cost more in steel for the frame than what I can buy one already made for. So, this project will get thrown on the back burner again.
  7. SurrealOne

    SurrealOne Former Member

    That's the trouble with trailers ... they spend a lot of time sitting unless you make money with them. I hated to spend what I spent on my tandem axle trailer, but I also know that most trailers don't lose a lot of value over time if kept in good condition -- as evidenced by pretty much every trailer I could find on Craigslist being $200-$400 dollars less than a new one.

    I searched every day for the better part of 7 months ... in an area 200 miles in diameter. That's why I bit the bullet and bought one, new -- because I'll certainly get my $200-$400 dollars in use out of it ... and can sell it for nearly what was paid for it after doing so ... if I ever want to. (I doubt I will. I acutally put a permanent tag on it. :) )

    That's food for thought, for you. It might make the cost a bit more palatable when you begin to look at that angle of it...
  8. PantheraUncia

    PantheraUncia New Member

    I know everything comes down to "weight" but it really amuses me to see trailers that don't have a full on rear axle that matches that of the truck pulling the trailer. Not that I need a 1/2 silverado axle or 2 under a trailer, but it makes life simpler...

    I know what the truck axle can take, and I can go anywhere and get normal tires for it and 6 lug wheels...
  9. SurrealOne

    SurrealOne Former Member

    My trailer would look funny with 34" Trail Grapplers all the way around! (Nevermind the sheer cost of that ... for a tire that will spend most of its lfe sitting.) It'd be kinda cool, though .. especially if I had matched rims. :)
  10. Pikey

    Pikey Moderator Staff Member

    I would like to see that! It would make loading a bear. I have seen a guy around here running 33's on a new silverado. He made a trailer out of a color matching bed. He is running the same tires and rims on the trailer.
  11. SurrealOne

    SurrealOne Former Member

    I'd like to be able to afford it. :)

    E_HILLMAN New Member

  13. PantheraUncia

    PantheraUncia New Member

    I am not saying to use 33-37 inch grapplers on the the trailer, but I see these 10 inch or 14inch white rims with tiny tires on it and wonder when the balloon is going to pop.

    Why not go with axles and wheels and tires that support a standard 6 lug 5.5 pattern and 265/70/16's or something.

    I would feel much safer with a "standard" wheel and tire even if I was only pulling 500-1000 or more pounds on a small trailer.... than little latex balloon tires..... :)
  14. SurrealOne

    SurrealOne Former Member

    Cost -- plain and simple. Reputable trailer manufacturers do match wheel and tire capacity to rated trailer capacity -- even on the smaller wheels/tires. Cost is also why most trailers are standard with bias ply tires ... and radials are usually an upgrade.
  15. tbplus10

    tbplus10 Super Moderator Staff Member

    My Jeep trailer used to run the same Pro Comp 36 M/T's and 16" wheels that I have on the truck that way I had more spares for the trail. But the trailer was only a camp/utility trailer 5x8 for carrying tools and camping gear, it looked nice lifted as high as the truck and could tag along most of the trail but not all, the height also made it easier to keep the hitch flat, but on the highway at any speed over 60 it swayed like a kite in the wind. The new owner has 33's on it and lowered it 3" and it handles much better now.

    Christopher have you thought of using sliding mounts for your fuel tank? A few inch's forward or back will make a big difference in your balance point and as you burn or add fuel you could adjust where the tank sits.
    I've seen this done on agriculture trailer that runs a 600 gl tank and pumps, the owner put a hand crank with geared wheel and a geared track on the trailer to make his adjustments. You could do something simpler maybe metal slides and use a come along with attachment points at either end of the trailer. Use floor mounted clamps to secure the tank to the trailer floor.
    The Gen set you want to be solid mounted and since it's weight wont change isnt a variable in the equation.
  16. SurrealOne

    SurrealOne Former Member

    Mmm, center of gravity ... another reason to use smaller tires.

    Sliding mounts make a lot of sense for the tank.
  17. Crawdaddy

    Crawdaddy Moderator Staff Member

    Sliding mounts does sound like an interesting method. However, I'm not sure how I can keep the tank from binding on the rails when trying to slide it. If I put the tank over the axle, it shouldn't matter as much anyway.

    I'm planning on looking at an old boat trailer-turned-utility trailer this weekend. As of now I don't know what the weight capacity of it is, but that will be the first thing I look at. I'm figuring a boat trailer should have a decent capacity.
  18. steved

    steved Former Member

    My 4x6 utility trailer runs LT265x75r16s...and has a cut down Dana 60 for an axle, and aluminum Dodge wheels. Its purpose built...purposely built to go anywhere I can take the truck. It probably has more miles on it and has seen more states than most trucks/owners on this forum.

    Building a trailer isn't that bad...you can also find a local trailer builder and have them custom build the frame. I priced a custom trailer done that way once near Shreveport, LA...a 6x10, tandem, 7k pound GVW was something like $600?? Again, this is a backwoods builder, not a commercial guy.

    If I were to do it again, I would keep an eye on Craigslist for a frame (no title), then use the materials to build it how you want it. Mobile home axles are cheap, and work great for a trailer intended to stay local (they don't balance very well)...I bought a pair of axles, springs, and six newer tires/rims for under $100. And then you have enough axle/tire/springs for 6,000 pounds (and they typically come with brakes).

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