Hitch position question or poll

[S_Parker]

So hi, I'm new here, done some readin here before but need someone with some experience. I've talked to a few people including a mechanic and rv place about placing the hitch back of the centreline. Many people say you can do it but I am unsure.

It's a 25 foot '77 vanguard round 5000lbs and my new truck is a 91 chev dually 1 ton.

There is a flat bed on the dually. With two I beams running atop the frame. And the hitch will be welded on top. I assume, I installed the last one but I'm taking this to a welding shop this time, the bed is extended about a foot past the fram. If I remember right from centre of rear axle to bumper was 67" or so and that means my bumper is touching my trailer. I know I want to have a few inches clearance, considering angling my corners of my flat bed as well.

But I'm just curios as to experience anyone has had with bringing the hitch back of centreline 3-6" people say yes but hitch manuals say different

[S_Parker]

Great thanks

[jaycocamprs]

Take a 62" string and make a arc from center over axle. Any thing outside that arc should be removed.

[S_Parker]

Thanks all for the help and opinions.

Well shovelled off a foot and a half of snow, got my line laser out and market everything out.

So from centreline to back of truck is 65"
As I said kingpin box to front is 67"

So I figured it could work if I install my hitch over centreline and I could maybe just angle to the two back corners of my bed.

Now here are my thoughts if I go an do that only leaves me with a few inches clearance. Not to sure if I'd be comfortable. To explain a bit more, I'm a full timer. First winter in a few years ive lived in a house. Most of my work is felling so I'm out in butfuck nowhere usually require some off roading. Last year I dented my box due to a big dip before a big hill. Hence why new truck I wanted a flat bed.

So a lot of times truck is twisted on way and trailer is twisted another. Soo I really wants to make sure I have space.

So I think I will chop some of my deck off make sure my hitch is where is should....

First question, better to have it over centreline or inch or so in front. As I said my hitch is installed is directly over the centreline now. This is my first 5er and was my first installation of a hitch.

Gonna be a big difference if I keep it right over the centreline vs an inch or two forward?

And gonna get someone to install this hitch as it's a lot of welding and not sure about attaching the brackets to the Ibeam vs the frame.


Next, I've googled a lot of deck designs to desire how I might wanna remake my deck. So I like the idea of that angled rear corners. Anyone have any ideal how much clearance I would need to give?


Thanks again for all the help do appreciate it

[laknox]

S.Parker wrote:

steveksfc wrote:
Can you mount the hitch behind the rear axle? Yes, Should you? I wouldn't if it was me. Would I have the bed shortened? Yes I would. I have seen several that the rear wheels were close to the rear of the bed. In fact some actually mount the hitch a few inches ahead of the axle. My first question is "What is the total length of the hitch box? You can install a longer hitch box on the 5th wheel. What was the truck used for before?

Hitch box is straight up and down. I've seen the kingpin extenders. But from what I think puts extra stress on different part of the frame in a way it might not of been ment for. Kinda of abandoned that thought a while back.maybe I'm wrong

Most FWs are built with an extended pin box in mind, whether one is used, or not. Personally, I wouldn't at all be afraid to replace the pin box with one that will give you the clearance to have the pin over or 1-2" ahead of the axle centerline.

Lyle

[boogie_4wheel]

Plenty of welding rigs with their hitches mounted behind the axle, so that it clears all their equipment in the bed. But they do have the welders mounted at the very front of the bed adding a fair amount of weight to the front axle. They are pulling trailers heavier than yours.

Try it with the hitch mounted. If it doesn't feel good, then think about modifying the flatbed.

[memtb]

steveksfc wrote:
Can you mount the hitch behind the rear axle? Yes, Should you? I wouldn't if it was me. Would I have the bed shortened? Yes I would. I have seen several that the rear wheels were close to the rear of the bed. In fact some actually mount the hitch a few inches ahead of the axle. My first question is "What is the total length of the hitch box? You can install a longer hitch box on the 5th wheel. What was the truck used for before?

As stated by others.... it can be done. With your truck and the light trailer...no problem. Though again as stated....it “will” tow a bit like a tow behind. I also would shorten the deck!

This was all repeated, to get this point. if you choose to go with a larger, heavier 5er, you have rendered your set-up a real “tow” liability. Most folks who start out small, light... quickly go larger. Greater pin weight with this set-up....would put you in a place you don’t wash to be!

[valhalla360]

Given a big 1 ton truck and a small 5k trailer, you can probably get away with 3-6" behind the axle. If you are talking a couple feet behind the axle, I would get nervous.

It won't be as good as the correct position but no where near as bad as a bumper pull setup in terms of towing feel.

Personally, I would go with a modest extension hitch box and put the hitch in the correct position. Yes, it will put more strain on the trailer frame but such a light trailer and modest extension should be minimal increase and highly unlikely to be an issue.

[4x4ord]

S.Parker wrote:

4x4ord wrote:
I deal is to have the king pin over or slightly ahead of the truck axle. Obviously that is not going to work in your case. You need to get the measurement from the kingpin to the front of your trailer. Then make the distance from the rear outside corner of your truck's bumper to the center of the truck's hitch a few inches more than that measurement. The further the king pin is behind the rear axle the more your fifth wheel will pull like a tag axle trailer.
It's not going to be ideal but it will work.

Distance from kingpin to trailer is also 67" so I assume my corners on my bed will 70-80 something lol not to sure how a tag axle trailer pulls

There are two main reasons a fifth wheel tows nicer than a tag:

1. While cruising down the highway with a fifth wheel in tow, if you turn the truck to the right the front of the truck immediately starts moving to the right.....very shortly after the front of the trailer follows, moving to the right as well.

With a tag trailer in tow any movement on the trucks front end initiates a movement in the opposite direction on the front of the trailer. So there is a natural tendency for a tag trailer to sway back and forth as it's being towed down the highway.

2. Because the hitch of a fifth wheel is generally over the truck axles no weight is taken off the steering axle....a tag trailer bounces 4 feet behind the rear truck axle causing negative effects on the steering geometry and traction of the front tires to road surface.


So the further you move your hitch behind the rear axle the more like a tag your trailer will pull. Because a fifth wheel is designed to transfer its pin weight over the rear truck axle they are designed with heavier pin weights. Even though your old trailer is only 5000 lbs It could have a pin plus hitch weight of 1700 lbs When loaded. If you move your hitch back 12" that 1700 lbs will only remove about 150 lbs off your front end.

[S_Parker]

steveksfc wrote:
Can you mount the hitch behind the rear axle? Yes, Should you? I wouldn't if it was me. Would I have the bed shortened? Yes I would. I have seen several that the rear wheels were close to the rear of the bed. In fact some actually mount the hitch a few inches ahead of the axle. My first question is "What is the total length of the hitch box? You can install a longer hitch box on the 5th wheel. What was the truck used for before?

Hitch box is straight up and down. I've seen the kingpin extenders. But from what I think puts extra stress on different part of the frame in a way it might not of been ment for. Kinda of abandoned that thought a while back.maybe I'm wrong

[S_Parker]

ScottG wrote:
I'm not sure I understand what your saying but I think with a 1T dually you won't have any issues at all with a trailer that size, no matter where the hitch is mounted.

Good luck!

Scott

Well basically everything I have been told or read when I installed my hitch on my 3/4 ton said 1-2" I front of the rear axle centreline because I want to keep my deck size. I'd like to have the hitch 3-6" back of centreline. Curious if people have done this or how it handles. Will it put extra stress on he truck. Curious about anyone's experience if they have done this.

[S_Parker]

4x4ord wrote:
I deal is to have the king pin over or slightly ahead of the truck axle. Obviously that is not going to work in your case. You need to get the measurement from the kingpin to the front of your trailer. Then make the distance from the rear outside corner of your truck's bumper to the center of the truck's hitch a few inches more than that measurement. The further the king pin is behind the rear axle the more your fifth wheel will pull like a tag axle trailer.
It's not going to be ideal but it will work.

Distance from kingpin to trailer is also 67" so I assume my corners on my bed will 70-80 something lol not to sure how a tag axle trailer pulls

[steveksfc]

Can you mount the hitch behind the rear axle? Yes, Should you? I wouldn't if it was me. Would I have the bed shortened? Yes I would. I have seen several that the rear wheels were close to the rear of the bed. In fact some actually mount the hitch a few inches ahead of the axle. My first question is "What is the total length of the hitch box? You can install a longer hitch box on the 5th wheel. What was the truck used for before?

[ScottG]

I'm not sure I understand what your saying but I think with a 1T dually you won't have any issues at all with a trailer that size, no matter where the hitch is mounted.

Good luck!

Scott

[4x4ord]

I deal is to have the king pin over or slightly ahead of the truck axle. Obviously that is not going to work in your case. You need to get the measurement from the kingpin to the front of your trailer. Then make the distance from the rear outside corner of your truck's bumper to the center of the truck's hitch a few inches more than that measurement. The further the king pin is behind the rear axle the more your fifth wheel will pull like a tag axle trailer.
It's not going to be ideal but it will work.