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TheHardWay

Towing Question about hitch extenders

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TheHardWay

So I'm thinking of getting a slide in pickup camper for my truck, but have some concerns when it would come to towing the boat. I found a 10' camper for sale. I have an 8' bed, so of course it is going to hang out the back. I have seen people using those hitch extenders to tow trailers when they have their campers on, but they just look like a disaster waiting to happen to me. Anyone here use an extender? I'm am sure they are perfectly fine.

However, my truck is lifted, and I use a 12" drop hitch to get my boat trailer to travel level. It seems to me that using that much of a drop, plus an extension might not be the safest way to travel . They are rated for 4500-6000lbs

http://www.etrailer.com/Hitch-Accessories/Draw-Tite/RP45292.html

Am I just being paranoid? Thoughts?

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Living the Dream

I think by having the extension it would reduce the tongue weight in HALF. I read a few of the reviews. I personally would not take the risk. I think the extension is great for bikes and extra load capacity but imagine the pressure it would put on on the receiver while towing a boat...

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electricjohn

The laws of physics tell me to tell you not to do it.

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jkendallmsce

I think by having the extension it would reduce the tongue weight in HALF. I read a few of the reviews. I personally would not take the risk. I think the extension is great for bikes and extra load capacity but imagine the pressure it would put on on the receiver while towing a boat...

it would actually double, not half...check out moment arm. you mutliple load (tongue weight) by distance, in Rum's case he is doubling (not sure the exact extension distance) but for this example...it is good enough for govt work.

http://www.engineeringcalculator.net/beam_calculator.html

use cantileaver, 3rd diagram down, plug in your numbers, and it is the second from the bottom chart

So where maybe he had 300 # w/o the extension, he now has about 600#, plus that 2 foot moment arm when moving around corners...well you square the velocity.

Edited by jkendallmsce

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Bill_AirJunky

I have a buddy who hauls a 23' LSV behind a Dodge dually with a slide in camper. Obviously he's using some kind of extension to do it, but I'm not sure how they are rigged or if there is more hardware to help handle the tongue weight.

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glasslake

Could you use a load leveler with it? This thing would really start to look like Frankenstein's monster's ride.

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mp3mike05

it would actually double, not half...check out moment arm. you mutliple load (tongue weight) by distance, in Rum's case he is doubling (not sure the exact extension distance) but for this example...it is good enough for govt work.

http://www.engineeringcalculator.net/beam_calculator.html

use cantileaver, 3rd diagram down, plug in your numbers, and it is the second from the bottom chart

So where maybe he had 300 # w/o the extension, he now has about 600#, plus that 2 foot moment arm when moving around corners...well you square the velocity.

It would decrease not double, think about using a breaker bar to loosen a nut, the longer the lever the less force you need to apply. Also to find out how much the tounge weight changes you really need to measure the distance from the wheels to the ball currently.

Edited by mp3mike05

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TallRedRider

It would decrease not double, think about using a breaker bar to loosen a nut, the longer the lever the less force you need to apply. Also to find out how much the tounge weight changes you really need to measure the distance from the wheels to the ball currently.

Your logic is exactly backwards. You can use a breaker bar to break something loose because you can generate twice as much pressure with a longer lever.

He is essentially talking about putting a longer lever on the hitch.

In other words, he could break his receiver off with half as much weight :biggrin:

But like you said, it would take some calculating to see if the force is doubled or just increased by a certain percentage.

Edited by TallRedRider

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Soon2BV

I will try to answer this with some basic engineering. I attached a PDF of a sketch.

Assume you have a bar that is 12" from the pin to the ball.

Also assume there is 6" 'back' from the pin to the back side of the receiver that is attached to your truck.

If you have a 300 pound tongue weight, you are creating a 300 foot-pound "moment" around the pin in the hitch bar. That pin is the pivot for this system.

The back side of the receiver has to react the 300 foot pound moment, and it only has 6" of a lever arm, so the effective load pushing up onto the back of the receiver is 600 pounds. that part of the system has to be strong enough to react that force.

When you go with a longer bar (assume that this one is 24" from the pin to the ball to make tha math easy), you have not changed the tongue weight. It is still a 300 pound load. But, you have doubled the moment arm (stress), because now that 300 pounds has a 24" (2 foot) lever arm. Your moment (bending stress) just went to 600 foot pounds (300 pounds x 2 feet).

This did two things. One, it doubled the force on the back of your receiver. It now has to react a 600 foot pound moment with 1/2 of a foot, so it is absoring a 1200 pound load.

The other thing this did is double the bending load on the 24" bar. This bar now has to withstand 2x the bending load that the shorted bar had. Depending on how strong the bar is, this means it could bend under load, or it could "tear" apart at the receiver.

Think of it like this - if you cannot break a bolt loose with a 12" breaker bar, what do you do? You get a 24" one. That lets the same force from your arm create 2x the torque on the bolt, so it will break free.

Another way - extend your arm and hang 20 pounds from your elbow. Not too hard to hold. Now move that 20 pounds out to your wrist and do the same. You arm is more likely to "bend" with the load further from your shoulder (the pivot).

Bottom line - I assume the hitches are designed for "standard" length bars and will not bend or break up to their rated weight. You are doubling some of the stresses on that system - and we do not know how much of a safety factor was in the design.

Going to a larger bar and larger receiver would buy you more margin if you still want to do this.

Trailer Hitch.pdf

Edited by Soon2BV

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jkendallmsce

It would decrease not double, think about using a breaker bar to loosen a nut, the longer the lever the less force you need to apply. Also to find out how much the tounge weight changes you really need to measure the distance from the wheels to the ball currently.

gotta disagree with ya. think about it, with the longer breaker bar, you have to use less force as you would with a shorter bar ....BUT with Rum's issue, the load (tongue weight) is a constant. P= load applied, L=length of moment arm...Look at the link...you'll see I am right.

unless the trailer changes, the tongue weight will remain relatively the same.. sure it will change if the incline changes, and will also change if you are moving (then you go from a static load to a dynamic load), but in a static case, the tongue weight remains the same.

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WoodyBC

Sure tounge weight stays constant, but think of the material. Not designed to stick out past the bumper 3-4 feet. It's designed for less. Go see a fabricator and tell him what you want. Have him (or her) weld up some braces and John Wayne the heck out of it with supports. Haul strong and safe, dont chance it with "I hope it will work" theorys.

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jkendallmsce

I will try to answer this with some basic engineering. I attached a PDF of a sketch.

Assume you have a bar that is 12" from the pin to the ball.

Also assume there is 6" 'back' from the pin to the back side of the receiver that is attached to your truck.

If you have a 300 pound tongue weight, you are creating a 300 foot-pound "moment" around the pin in the hitch bar. That pin is the pivot for this system.

The back side of the receiver has to react the 300 foot pound moment, and it only has 6" of a lever arm, so the effective load pushing up onto the back of the receiver is 600 pounds. that part of the system has to be strong enough to react that force.

When you go with a longer bar (assume that this one is 24" from the pin to the ball to make tha math easy), you have not changed the tongue weight. It is still a 300 pound load. But, you have doubled the moment arm (stress), because now that 300 pounds has a 24" (2 foot) lever arm. Your moment (bending stress) just went to 600 foot pounds (300 pounds x 2 feet).

This did two things. One, it doubled the force on the back of your receiver. It now has to react a 600 foot pound moment with 1/2 of a foot, so it is absoring a 1200 pound load.

The other thing this did is double the bending load on the 24" bar. This bar now has to withstand 2x the bending load that the shorted bar had. Depending on how strong the bar is, this means it could bend under load, or it could "tear" apart at the receiver.

Think of it like this - if you cannot break a bolt loose with a 12" breaker bar, what do you do? You get a 24" one. That lets the same force from your arm create 2x the torque on the bolt, so it will break free.

Another way - extend your arm and hang 20 pounds from your elbow. Not too hard to hold. Now move that 20 pounds out to your wrist and do the same. You arm is more likely to "bend" with the load further from your shoulder (the pivot).

Bottom line - I assume the hitches are designed for "standard" length bars and will not bend or break up to their rated weight. You are doubling some of the stresses on that system - and we do not know how much of a safety factor was in the design.

Going to a larger bar and larger receiver would buy you more margin if you still want to do this.

well said. The link I provided shows exactly what you said above. ANd will provide the shear, bending diagrams for a simple beam, which is what this case is.

Edited by jkendallmsce

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Danno

We used tow a 23 foot race car trailer behind our 12 foot camper. Out trailer was over 9000#. No problem with the hitch extender.

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Molarbu

I saw two heavy duty trucks with piggy backs and pulling Malibus at Priest Lake last year. Both had hitch extenders. I don't have any experience or knowledge about how effective it is, I'm just telling what I saw.

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TheHardWay

Thanks for all the feedback guys. The physics was much more than I was expecting haha

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jkendallmsce

We used tow a 23 foot race car trailer behind our 12 foot camper. Out trailer was over 9000#. No problem with the hitch extender.

class IV has a max hitch weight of 750# and a max trailer weight of 7500 #

class V has a max hitch weight of 1200# and max trailer weight of 12,000#

also depends on what the vehilce is rated for (which class of trailer hitch)

Edited by jkendallmsce

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Soon2BV

The physics was much more than I was expecting haha

Sometimes it is hard to control my inner-engineer...

Another option, I wonder if anyone makes a trailer dolly (hitches to truck, 2 wheels, ball mount) like they use when they make tandem semi trailer hook-ups?

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nyryan2001

Using a hitch extender is akin to using a breaker bar over a ratchet. Depending on your setup, that 12-24" rear shift in the tongue weight can have dramatic effects. Tongue weight will remain the same, but the "lift" on the front of your truck with be much more pronounced.

FWIW, they do make campers without the overhang in the back, and others that are made that still allow you to tow WITHOUT a hitch extender...perhaps one of those could meet your needs.

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TheHardWay

FWIW, they do make campers without the overhang in the back, and others that are made that still allow you to tow WITHOUT a hitch extender...perhaps one of those could meet your needs.

Yeah, I have seen those styles too, and that would be ideal. If I were to buy a new camper, this is the route that I would go, but I am looking at used ones, and the price of the one I found is almost too good to pass up.

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Mechmaster

I used to run an 8' slide-in camper on my 6'-6" bed Duramax with the tail gate down. This configuration yielded approximately an 18" overhang past the bumper on my truck (due to the tailgate being down).

As has been said, a hitch extender will derate the capacity of your hitch. In my case, I would have needed to go with a class 5 hitch + extender to get the capacity I needed for my '98 VLX (which is quite a bit smaller than your boat). The new hitch, extender, and ball mount were also fairly expensive.

What worked for me was this: http://www.etrailer..../Curt/D900.html. This ball mount is 16 inches long (it was the longest one I could find) and worked with my conventional class 4 hitch on the Duramax. The rated capacity with my configuration was 7,500 lb (if you have a class 3 hitch, it will be less).

The tongue on my trailer was long enough to slide under the remaining 2" of overhang from my camper and still let me turn without hitting the boat.

Edited by Mechmaster

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hukk

I have a 9.5 foot camper on a 8' truck bed. I use a SuperHitch and SuperTruss drawbar which are mfg. by Torklift. A safe and strong way to tow with and extended drawbar. I also use the Torklift tiedown system to secure the camper to the truck. Another alternative for an extended drawbar is by Reese, their Titan system. The SuperHitch and Titan are both Class V rated.

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Devin Perry

Here is a link to the super hitch here This is what I would be most comfertable with.

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TheHardWay

My truck is a 1 ton so I am fairly certain it is a class IV hitch. Correct me if I am wrong, but a class V has a 2 1/2" receiver, right?

Any idea of what those super truss hitches run? That looks like a stout set up.

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