Extending Trailer Length

[RGRIFFIN]

Hello,

I would appreciate some opinions. My business partner and I have a heavy duty 20' tandem axle bumper pull trailer that we think we can convert to a
40' trailer by chopping the tung, extending the front by 20' and then welding the tongue back on. I have checked with the licensing department in our state and they have stated that a 40' homemade trailer complies with the rules as long as the gross weight is less than 4000 lbs, which it would be.

We think the axles are OK where they are and we believe that extending it does not pose any problems from a strength or hauling down the road perspective.

As far as why we need a 40' trailer, we build custom tower stands for deer hunting and have a big order several states away and with fuel prices are trying to avoid two trucks and trailers. A 40' trailer would allow us to take one trip. The stands are not heavy so weight is an issue just space. We are also trying to spare the expense of purchasing a new or used trailer.

The construction of the trailer is heavy C channel runners with "ribs" going out from the C channel to the edge of the trailer. The tongue is the typical V shape and it extends under the trailer about 2.5' to 3' until it each V side of the tongue reaches the edge of the trailer. We we weld the tongue back on in this same fashion. We would plywood the trailer bed. Again it will only be loaded with about 800 lbs or cargo.

Does anyone see any blatant errors with this plan? Has anyone here ever done such a thing before as extend a trailer length? Does this sound like a sound plan?

I have done my share of welding and cannot see any problems with it but would like to get some second opinions.

Thank you for your time,

Rob

[whateg0]

Well, I've pondered this. And I'm still pondering it. I've got a 12' trailer with a long tongue that I'd like to replace with a 20'. Or I could extend this one.

My trailer, which is pretty light still tops the scales at 1150#. It uses 4" channel, some 3" channel, and 2x2 angle cross-ways. Making it 3 times the length would make it about 3500#. You called your trailer a heavy duty one. If it truly is, I think you'd be hard pressed to fit the trailer under the 4k# limit. Mfr'd trailers of the 20' variety normally have frames of 5-6" channel and cross beams of 3" channel or 2x3" angle. I'll have to do some figurin', but with a payload of 800#, you'd have to stay under 3200#. That's not much weight. Not saying it can't be done, but I'd err on the light side, because weight seems to add up when you're trying to stay light. Heck, a pair of axles and tires is going to weigh almost 500#.

On the extending part, don't cut the tongue off and try to weld it back on. Instead, to make it easier, chop it behind where the tongue meets the frame rails. Then weld in the stretch portion. I'd box the backside with a single piece of plate at least as thick as the web of the channel, extending well past the joint in both directions.

I don't know squat about your welding skills, but this is something to do a good job on. With a trailer that long, it's going to have some tremendous stresses, especially when traversing bumpy or wavy roads. The back of the trailer is going to want to bounce, causing the frame to flex behind the axles. The section between the axles and the hitch are going to want to bounce also, causing the frame to flex there. My TLAR engineering tells me that you'd do well to go at least 1.5X the height of the existing frame rail to counter that, which of course adds more weight. Anyway, you don't want this thing to bounce itself apart going down the road. And because things like deer stands are often 'off the beaten path' anyway, the roads it's going to have to go over are likely to be even worse.

You mentioned leaving the axles where they are. Do you mean that if the center line of the axles is 8' from the rear of the trailer now, you'd keep it 8' from the rear of the trailer? That'll make it about 35' between the hitch and the axles. That's a big turning radius. Again, think about the roads you'll go down and decide if you can fit it, and turn around if you need to. Aside from that, if you put that much of an imbalance there, the truck is not going to handle safely because you'll have probably around 40-45% of the trailer's weight on the bumper of the truck. NOT SAFE!

You can take my words with a grain of salt, as I'm no expert, but at least from the cheap seats, this seems like a bit much.

Dave

[Mr Jimi]

Many years ago, I towed a 50' ham tower behind my Corvair with a permit and an orange flashing lite. I chained the bottom of tower to a small trailer and I mounted a ball coupler to the top and ran lites to the rear and it worked fine. very close to the same way they move phone poles
nothing to it
With what you want to make you will have a huge swing out to clip stuff with, not good
show us some pictures, we love pictures here
Jim

[Scott Young]

why don't you just use the tree stand as the trailer? all you do is mount a rear axle dolly that is pinned in place and attach a tongue that is pinned in place. the deer stand is the actual trailer framing. when you arrive on sight, pull the pins and load the axle and tongue into your truck and set your deer stand upright. you can either design the tongue and trailer to hold the keepers and the pin encloses the deer stand members, or you can weld ears onto the stand that will remain after the attachments are removed. once you get it built you can take it down to the dot and get the correct paper work. i hauled several stands this way.

we also have a setup like this that that we use at work to haul billboards with. now they require escorts due to height and width issues.

[mudbug]

I'm no expert by any stretch,but I thought the proper balance was around 60% in front of the axles centerline & 40% behind which would require -two- section cuts to find that balance. I would also think the front section should be after the tongue to avoid rebuilding that structure. It's much easier to add straight sections where needed to stretch the trailer,rather than cutting and building the tongue.

I don't know how many states you have to cross or the laws in those states,but you might find it easier to hook two trailers in tandem to carry the load. If the states you cross allow such a rig(most do) you could either rent an extra trailer(and dump it at your destination) or pull it up on the other trailer once you unload(nicer ride home loaded). I've seen lots of boats hauled this way as well as trailers from the manufacturers. They were stacked high with whatever they were hauling(and looked heavier than you describe). This way you can carry smaller loads without having to pull a 40' all the time-- just when needed. Your 2nd trailer could even be a 16' maybe,unless the 20' is absolutely necessary--Think $$$ here and work stretching the trailer you have.The stress mentioned above is a factor.

Just some food for thought---You did ask--LOL Good Luck!

[MAC702]

Without being able to be blamed for any advice taken, I would also suggest at least considering lengthening the portion between the tongue and wheels only half (or so) of what you need and then adding the rest to the part behind the wheels. That (or something similar based on your particular load) can keep it more balanced after lengthening.

[taylorkh]

Is this a bumper hitch trailer? A number of years ago I had a building contractor lined up to do some repairs for me. His crew jackknifed his trailer exiting the interstate. By the time he got to the scene the trailer had been picked clean. His insurance company refused to cover the claim because the trailer was too long to be pulled by a bumper hitch and required a 5th wheel. At least that was his story.

Ken

[whateg0]

I know there are auto transporters around here that use bumper-pull trailers long enough to haul 2 cars. That has to put them in the 40' realm. This allows them to haul 3 vehicles - one on the roll-back and two on the trailer.

Dave

[59halfstep]

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[Dog]

Their is a rule of thump to follow on fow far the axles shopuld be from the back of the trailer. Like others mentioned a 60/40 portion is correct I think. We had one that was long on the front side of the axle and a bent tounge was the result. I would not do it.

Another thought, i made a boat trailer into a utility trailer for the challenge. I would not do that again. To much cutting and welding and keeping things sguare. Start from scratech with new iron the best imo.

[triptester]

Beware of excess tounge weight most hitches even those rated for 10,000# towing are only rated for 500# tounge weight. A 5,000# trailer with 20% tounge weight would equal 1,000#

[Hammack_Welding]

Yes, you can extend it, but not like you are wanting to. There's no way to add 20' to the front of an existing bumper pull trailer without changing the axle location, and still manage to pull it on the back of the truck. You would stand a better chance if it was a goose neck or fifth wheel, but it will be just too much tongue weight for a bumper pull. Something else to consider. You say that you will be delivering your product to another state. You will also have to meet the laws and regulations of the states you will be traveling thru. Not just the one you live in. Also since this is a commercial venture you will need DOT numbers on your vehicle, and meet there regs as well.

[dabar39]

By the time I'm reading this I really hope to say DON'T EVEN TRY THIS.

There are many, many reasons for not doing this by the op's original question.

First off, If you gotta ask, you really don't know what you are doing and shouldn't be doing it to begin with.

Second off, A bumper pull should not even be considered at 40' much less anything over 20', and I'm not a big fan of anything over 20' as a bumper pull either.

This should be considered as a fifth wheel or gooseneck type of set up only.

Let's forget all about the stresses and flex and weight involved in trying to go with a 40' bumper pull, think of the logistics of the thing. To get the proper tongue weight (which is a guess at best) you need to place the spring equalizer at the 60% rearward mark. that would place the rearward axle at or about 304" from the front of the trailer deck meaning that the other 40% or approx 174" or 14 1/2'' of over hang would be trying to take up the 11' of available traffic lane when attempting to make a turn.

I have a few other reasons why not to do this but we'll start here and see where it goes if anywhere. Dave

[Sandy]

There are all kinds of specialty trailers out there. You see them every day. Yes they may be impractical for other uses and a handling nightmare, but they do exist and are many times necessary. Not everything has to fit the mold.

Legality is the biggest issue. The length limits can vary from state to state. These length limits are pretty much ignored for RV's or allowed through commercial licensing, but I don't know that they would be ignored for an ordinary 'joe' pulling a tower through small town USA.

As a parallel train of thought, it seems logical to make these towers sectionalized. Either ten or twenty foot increments with bases, mid sections and caps universal. Ease of fabrication, ease of transportation and ease of installation.

[whateg0]

...
Second off, A bumper pull should not even be considered at 40' much less anything over 20', ...

Yep, old post. Wonder why it was resurrected...

Anyway, 40+' trailers are commercially available in tag configuration. Heck, even standard racecar trailers are often of either 24' or 28'.

Here's a sample of a trailer that is commercially available.
http://www.trailersforless.com/2car_tag.htm

As far as the 60/40 rule, it is foolish to say that the axle placement must be a location X. If you are pulling a load that is heavily biased in such a way that most of the weight must be placed at the rear of the trailer, a trailer built to haul such a load should not have the axles at the 60% point. In fact, the axles in this case would likely be best placed near the rear of the trailer. Blanket statements like, "...you need to place the spring equalizer at the 60% rearward mark..." are just as dangerous as the guy who doesn't know, especially if the person building the trailer does not understand the reason behind the statement or the ramifications of altering the set of conditions that apply.

Dave

[down19992000]

i am sorry but i have to agree with pretty much everthing dabar said. if you are asking questions you might wanna think twice about this.

[dabar39]

Yep, old post. Wonder why it was resurrected...

Anyway, 40+' trailers are commercially available in tag configuration. Heck, even standard racecar trailers are often of either 24' or 28'.

Here's a sample of a trailer that is commercially available.
http://www.trailersforless.com/2car_tag.htm

As far as the 60/40 rule, it is foolish to say that the axle placement must be a location X. If you are pulling a load that is heavily biased in such a way that most of the weight must be placed at the rear of the trailer, a trailer built to haul such a load should not have the axles at the 60% point. In fact, the axles in this case would likely be best placed near the rear of the trailer. Blanket statements like, "...you need to place the spring equalizer at the 60% rearward mark..." are just as dangerous as the guy who doesn't know, especially if the person building the trailer does not understand the reason behind the statement or the ramifications of altering the set of conditions that apply.

Dave
Maybe I'm speaking out of turn here and you may have more experience building trailers than I do but I would doubt it. I am a trailer manufacturer and I have personally built 532 trailers to date and can tell you that you are comparing apples to a death trap.

You showed a link to a professional builder who has used a properly engineered truss design (and I can't tell by the picture but probably a torque tube as well and certainly over the op's weight limit) and compare it to a C channel perimeter frame that was not and is not designed to be extended to 40 feet. Do you have any idea of the amount of flex that this trailer would have? Do you have any idea of the change in forces that would directly and dramatically change the tongue weight continuously? Do you have any idea of how unstable a set up like this would be at highway cruising speeds? I'm not even going to get into areas like metal fatigue or weld fatigue but hopefully you get the idea and think again before you tell me I'm handing out DANGEROUS advice. I also think you should go back and re read your very first post on this thread and tell me I'm saying anything different than you said in that post. Oh and by the way, look at the axle placement of your linked picture, I'd say that's about a 60/ 40 split there



Axle placement on ANY bumper pull trailer should be at a 60/40 split with no exceptions otherwise the axle manufacturers would say to put them anywhere you want them at, but at last check they specify the 60/40 rule to maintain proper tongue weight. If you don't believe me look at the Dexter axle site or any number of other axle suppliers for their placement specs.