Telescoping Trailer Tongue Extension Question

[adamis]

I currently have a 12 foot cargo trailer and I'm looking at purchasing a 26 foot travel trailer both of which will be towed by my truck with camper for business purposes (one at a time of course). I've considered having a local welding shop modify the tongues of both trailers to have a telescoping trailer tongue that can be extended / retracted depending on whether I have the camper on the truck or not. I already have a super truss hitch extension in place but I'm thinking that having the ability to extend the trailer tongue as needed will be more convenient for my use then having to add and remove the super truss. Doing a quick google search seems to be turning up a few results that look interesting.

On my Bigfoot 10.6E Camper it does extend past the bed of the truck by ~3ft but it does not drop below the height of the bed. I think I should have plenty of clearance for when the truck and trailer are at extreme angles to each other. Most of my time I'll be on pavement anyway and about the most extreme angles I'll likely encounter are driveway entrances and speed bumps.

I think I would need about 3ft of telescoping tongue to fit my needs. Does anyone have any experience with such a setup?

I found an example of someone doing this type of work here:

[Reddog1]

Looks great. I would really tighten those chains though, for several reasons.

Wayne

[adamis]

Just got the trailer back today. Very pleased with the quality of work done. Had it taken care of by San Martin Specialty Shop. I've only driven it a few miles but so far no problems. I went up a somewhat steep parking lot entrance to see how close the extension would get to the trailer and I had plenty of space.

One thing extra I had done was to raise the rear legs of my Bigfoot Camper. They typically extend past the bumper about 8" but the guy raised them as high as they would go. This gives more margin for dips and angled areas.

Photos on Google Plus

[adamis]

stevenal wrote:

adamis wrote:
Adding 75lbs of metal on the tongue can easily be offset by packing some weight over the axles or slightly behind to act as a counterbalance to offset the weight.

Still not getting it. It is not the few pounds of added metal, it is the changing lever arm length. When extended, you would want to move cargo forward not back in order to keep the same tongue weight.

Fair enough. The point of my statement though is that any changes made to the length of the tongue will be able to be offset by how the trailer is loaded. It's a fulcrum and optimal weight distribution can be achieved any number of ways. In my own case based off of the weights I anticipate hauling I just don't think it will make any appreciable negative difference. There should be a marked improvement on the truck because of the reduced lever arm from eliminating the super truss.

[stevenal]

adamis wrote:
Adding 75lbs of metal on the tongue can easily be offset by packing some weight over the axles or slightly behind to act as a counterbalance to offset the weight.

Still not getting it. It is not the few pounds of added metal, it is the changing lever arm length. When extended, you would want to move cargo forward not back in order to keep the same tongue weight.

[Bedlam]

Agreed. I learned on a short narrow trailer with 8" rims that was only 8' between the hitch ball and axle. I always wondered why it was so much easier for others until I tried a longer trailer.

[Reddog1]

You will discover it will react differently when backing up. The shorter the distance from the ball to the axle, the quicker it reacts. Personally I prefer the longer tongue.

Wayne

[adamis]

Trailer is at the shop, not certain how long it will be, could be a couple of days or maybe a week or two.

I have a thought for the many comments regarding tongue weight and such and how much heavier it will be with the modifications necessary to make this plan work. Yes, the tongue will be heavier but the only time that will actually matter at all is when the trailer is empty and when it is empty, a slightly heavier tongue isn't going to make any difference to the truck carrying it for practicality purposes.

What is really going to matter the most is how the trailer will be loaded and where the weight is going to be placed within the trailer. Adding 75lbs of metal on the tongue can easily be offset by packing some weight over the axles or slightly behind to act as a counterbalance to offset the weight. If we were all loading our trailer by the book, we would have to get a scale out and carefully monitor what we place where. Perhaps some people do that currently but I'm guessing the majority of us probably load the trailer by the more "guideline" approach of trying to keep the weight in front of the axles but then cramming stuff where it will fit and hoping the door will close. The point of my example is that as careful as we should be to ensure the weight is distributed correctly, often times we go with less than optimal and seem to be okay as long as we are not grossly outside the margins.

For my own uses, the trailer will likely never be loaded anywhere close to capacity (it is a 2 axle 12' trailer) so I'm pretty confident the added weight to the tongue is going to be a non-issue.

[Rubiranch]

So, whats the final verdict? 😄

[ticki2]

mkirsch wrote:
The one thing I would not be concerned about is the changing tongue weight.

First off the structure of the telescoping tongue only ADDS weight to the tongue. Second off a longer tongue tends to make the trailer more stable, requiring a smaller percentage of tongue weight.

But, it's still going to be heavier than it is now, extended or retracted. If it tows good now it will tow as good or better extended.

Not necessarily . It will add more overall weight to the trailer but as the tongue gets longer less weight will be applied to the tongue and more to the trailer axle on a single axle . It will be somewhat disproportionate because you are adding weight closer to the coupler , not at the COG of the trailer .A double axle is a little more complicated . As the front axle starts to unload you also change the fulcrum point .

[adamis]

Just a quick update... I took it over to the local trailer fabrication shop. I explained what I wanted, the guy took some measurements and gave me a price. Trailer is now in the shop and we will see what the results look like. I'll be certain to post some pics in a couple of weeks when the job is done.

One thing I may have to look at is that the rear jacks on my bigfoot might need to be raised about 8". I'll have to see once the trailer is hitched up.

[HMS_Beagle]

mkirsch wrote:
....Second off a longer tongue tends to make the trailer more stable, requiring a smaller percentage of tongue weight.

But, it's still going to be heavier than it is now, extended or retracted. If it tows good now it will tow as good or better extended.

Exactly right.

[stevenal]

mkirsch wrote:

First off the structure of the telescoping tongue only ADDS weight to the tongue.

I think we can safely neglect the weight of the added metal for this setup. The point is that when extended you have a longer lever arm than when retracted. If the center of gravity is a fixed distance in front of the trailer axle, this moment must be offset by the moment produced at the hitch. Since we know the trailer is not spinning end over end, the sum of the moments must be equal to zero; and this must be true for both the extended and retracted positions. The weight at the tongue therefore changes. In the extreme example, the tongue weight requiring a jack will be easily lifted with one finger when the lever arm is made long enough.

[mkirsch]

The one thing I would not be concerned about is the changing tongue weight.

First off the structure of the telescoping tongue only ADDS weight to the tongue. Second off a longer tongue tends to make the trailer more stable, requiring a smaller percentage of tongue weight.

But, it's still going to be heavier than it is now, extended or retracted. If it tows good now it will tow as good or better extended.

[wnjj]

towpro wrote:
think about this.
I currently have an object that is 19' long and weighs 5000 lbs.

1) The center of gravity. for this load is is 9' back from front.
2) There is a pivot point 10' back from front. (axle)
a) This pivot point is 10% behind the center of gravity.
b)In Theory to lift the front of weight, since its 10% more weight forward on pivot location, it would take 500 lbs (10% of 5000 lbs) of force to lift it (tong weight)

4) now if I extended a leaver on front of this weight, out 5' (50% more), would it still take 500 lbs of force to lift the front of this weight, or 500 lbs - 50% leaver = 250 lbs?
I mean your fulcrum is still the axle, but we just added a longer leaver (hitch extension)

I don't think hitch length extension is multiplying weight, I think its reducing it?


but now if I put a 5' leaver out of back of truck, that is fixed to truck, with center of truck as axis,
and have a pivot point where it connects to the front of this 500 lb weigh, (like a truss or hitch extension) that will multiply the 500 lb weight that is on the pivot end

Changing the tongue to axle length from 10' to 15' (i.e. 1.5x or 3/2) would result in 2/3 of the tongue weight. Force x distance is constant between the 2 scenarios.