5th Wheel pin placement

[Whiskey Wish]

I have a converter, some call it a dolly, I use under my 5th wheel flat deck so I can pull it with a bumper pull, a quad or my tractors.

It has a conventional 5th wheel hook up on a single axle. Recently I did some re-working and re-welding on it to improve it and I wanted to move the 5th wheel pin ahead to put a small amount of weight back on the tongue of the converter.

I did get the 5th wheel pin ahead by approx 2 inches past the center line of the axle but the tongue is still weight neutral. It will almost hang balanced in mid-air with 14,000 pounds on the trailer.

My question is: Does anyone have any experience as to how far forward I have to move the 5th wheel pin to get some small percentage of weight on the tongue of the converter?

Trial and error is difficult because it means cutting, re-welding etc. so I thought I would ask around in case someone has the knowledge and is willing to share it.
Regards,
Dave.

[G Kenworth]

If you measure the distance from the axle to the tow hitch, take 10% of it and install your 5th wheel hitch that distance in front of the axle, should give you 10% tounge weight. Wouldn't it?

[Whiskey Wish]

You may be absolutely correct...I simply have no idea. Without going outside and actually measuring it I would guess it approx 6 feet or 72 inches. Using your 10% concept that would mean I need to be 7.2 inches in front of the axle to get 10% of load weight onto the hitch. 14,000 pounds loaded would make 1,400 pounds on the hitch.

( I would of course get the proper measurement first)

That means I have some serious welding to do.....lol. I was thinking in terms of 1 or 2 inches but to repeat, I have no idea I am just guessing.

I see the logic in your math though. Thanks for the input.
Regards,
Dave.

[ditch donkey]

Originally Posted by Whiskey Wish

That means I have some serious welding to do.....lol. I was thinking in terms of 1 or 2 inches but to repeat, I have no idea I am just guessing.

I see the logic in your math though. Thanks for the input.
Regards,
Dave.

Of you're already into some serious welding, I would put the hitch on a rail, that I could pin every two inches. That way you don't have all your eggs in one basket. Plus if you use your quad to pull it around 1400lbs tongue weight might be a bit much. Might be nice to lighten it a bit. It would also allow you to tailor the tongue weight if your pulling a diffrent trailer. Empty or full.

Just another idea anyway.

[Gunfighter]

To me it sounds as if the problem is your trailer design. If the trailer hitch is hanging netral while loaded, the problem would be in the axle to pin length of the actual trailer, not your hitch center line on the converter.

[Gunfighter]

How much weight actually transfers to the converter. I may have read your problem wrong?

[Dacotensis]

Originally Posted by Gunfighter

To me it sounds as if the problem is your trailer design. If the trailer hitch is hanging netral while loaded, the problem would be in the axle to pin length of the actual trailer, not your hitch center line on the converter.

This is what I was thinking as well

[JB_AOL]

Way too many variables.

Honestly.. If this is a farm yard only thing (low speed <10-20kmhr). I wouldn't worry too much about it.
If you are trying to make it versatile enough to pull with a quad & tractor (no idea what size), I'd leave as little tongue weight as possible on the dolly. The important part is having weight transfered to the dolly wheels. Not necessarily to the tongue.

NOW if you plan on using this behind trucks/on roads.. Then yes spend the time to figure out the proper tongue weights. Unfortunately this also means your quad will be severly overloaded.

I'd do an adjustable style hitch, build some kind of receiver that you can adjust the location of the pin (easily), depending on trailer load and tow vehicle.

[Whiskey Wish]

Thanks everyone for your ideas and tips.

As usual details matter and I was perhaps a bit vague.

I have a 24 foot tandem axle commercially built 5th wheel trailer. I use it behind my truck for hauling loads up and down the highway like anyone else. I also use it to haul hay off my fields in the fall and at this time I use a converter so that I can pull the trailer behind one of my tractors.

Rarely I might use a quad and the converter to move the EMPTY trailer around in the equipment yard. ie pull it forward to the shop so I can service the bearings on the trailer. The converter does not leave the farm... as in trucking up and down the highway. It does go down the gravel roads between my fields.

I have no issue with weight distribution when I am pulling the trailer as a conventional 5th wheel behind my truck.

I recently re-did a bunch of welding and moved my 5th wheel rails ahead on the converter in an attempt to put some weight on the tongue of the converter when it is loaded. I wanted this for two reasons;
1. This prevents the tongue from lifting in the air when loading or dollied off loaded.
2. This would put some weight on the rear axle of the tractor when pulling to give some added traction.

I did get the center of the 5th wheel pin about 1 1/2 - 2 inches ahead of the centerline of the converter axle but I am still weight neutral on the hitch of the converter. I was hoping someone might be able to give me an idea how much ahead of the centerline of the converter axle I need to be to actually put some weight on the tounge when loaded and I could avoid the "trial and error" method due to the amount of welding involved.

G Kenworth was kind enough to provide me with his idea and the math made sense to me.

I see the benefit of adjustable rails and will give that idea some consideration.
Regards,
Dave.

[G Kenworth]

A picture is worth a thousand words.