5th wheel hitch position in the bed

[KKELLER14K]

Can anyone tell me or does it matter that the Kingpin head is directly over the centerline of the rear axle? Or is it just a matter of you having enough clearance to keep from hitting the cab and side rails and Kingpin base position is only relevant to clear the bed sills (supports underneath) with a fixed rail system?

[JIMNLIN]

I always tell my hitch installer where I want the pin/GN ball location in my trucks.
I prefer zero over the rear axle for a short bed truck. This gets the trailer as far as possible from the trucks cab.....and allows the most distance when using a sliding hitch.

On my long bed trucks for my heavy GN trailers and 5th wheel RV trailers I have the pin/ball 4" in front of the axle.

[Arcamper]

My pin weight is 3,400 and it only shifts 48 lbs to the front with the pin 2 inches forward of the rear axle. I set it up first right over the rear axle but was told on here that was wrong so I moved it. Could not tell any difference.

[Cummins12V98]

Industry "standard" is 2" forward of axle centerline. Old school when you had to lay out the hitch and do all your bracket placement that was the norm. I run my B&W RVK3600 puck hitch full forward. I have at least 5,800# pin and less than 200# is added to the front axle.

[Hannibal]

I had two sets of bed rails in my short bed CC F250 with our previous 5th wheel with 1900 lbs of pin weight. The forward set put the pin 2" ahead of the rear axle. The rear set put the pin 12" behind the rear axle. I honestly couldn't tell the difference towing in either position other than with the hitch in the rear position, I could make full lock U-turns without contact with the cab. Behind the rear axle is common with trucks hauling welding machines in the front of the bed.

[mkirsch]

The weight transfer difference 2" ahead or 2" behind the axle is minimal. It's real simple to calculate out and even if you put some ridiculous pin weight like 5000lbs, the difference is minimal.

A while ago I figured this out for truck campers: A 5000lb truck camper with it's COG 6" behind the rear axle has the same weight transfer effect on the truck as a 500lb tongue weight on the receiver hitch. You can equate that to a 5000lb pin weight.

1/3 the distance, and the weight transfer off the front wheels is equivalent to having a 166lb tongue weight on the receiver hitch.

If you've only got a 2500lb pin weight the effect is the same as 83lbs on the receiver hitch.

[KKELLER14K]

I will mention another comment the B & M person said. They said that the adjustment pattern on the base of their hitches is more for the trailer clearance than any kind of weight distribution or stability issues and just what some have said here....a couple of inches forward is better but over the axle is ok to. So in reality, after all is said and done, it's no big deal in the end.

[rhagfo]

mowermech wrote:
I have to ask, even though some may say it is incredibly rude:
Exactly what is wrong with following the instructions printed by the hitch manufacturer?
That is what I did when I installed a Husky fifth wheel hitch in the bed of my old 1994 Dodge Ram 3500 CTD dually. It worked great!

X2, rail systems come with a small book it seem of instructions, based on brand, style, and of the TV. The seem to be placed such that the use the strongest parts of the bed of the TV. This usually placed the pin either directly above the axle or slightly a head.

[IdaD]

As long as you're within a few inches of the axle either way I don't think it makes much difference. The geometry is such that it simply won't make much of a difference in the front axle weight or leverage on the tow vehicle.

[KKELLER14K]

I had a discussion with B & W today. Their advice was no surprise. This was their online answer...

Good afternoon Kevin,

Thank you for your inquiry. Generally when towing a trailer you will want the load positioned directly over the axle or slightly forward. This will allow the trailer weight to be dispersed through the truck frame and suspension evenly and provide a comfortable tow. As far as which position is truly better determines a lot on personal preference. If you have the clearance, I would recommend placing the hitch head slightly forward of the axle. However, towing directly over the axle is perfectly fine as well. If you have any questions, or if I can be of any further assistance please let me know.

Well that's the game. I want to thank you all for pitching in on the discussion.

[mowermech]

I have to ask, even though some may say it is incredibly rude:
Exactly what is wrong with following the instructions printed by the hitch manufacturer?
That is what I did when I installed a Husky fifth wheel hitch in the bed of my old 1994 Dodge Ram 3500 CTD dually. It worked great!

[KKELLER14K]

Thank you, thank you, I just needed that.

[goducks10]

KKELLER14K wrote:
The B & W patriot 18k is what I have and the head adjustments are numerous. The rails that the base is mounted to are limited to the bed supports of the truck you have and varies from truck to truck. I so happen to have a long bed. So can anyone explain why 2 inches forward is the optimal spot? Saying that it should be there, ok, but why should it be there? So regardless of where the base is mounted I can move that head all over the place. I can see maybe why mounting it just forward of the centerline would be a good thing vs. aft of center for stability geometrically... Now I also see why a slider would be necessary for a short bed for cab clearance in tight spots but when one of those are pulled up close to the cab I'm guessing your still shooting for the 2 inches ahead of the rear axle centerline? I'm learning here and it's starting to make sense. I can see some other brands are limited to fine tuning the Kingpin position so where the bed rails are mounted... that is what you get. Thanks everyone for your info...

Here's a real world opinion. I have a B&W Patriot on rails. I have a LB 2500. I've adjusted the hitch to be as far forward and rearward as possible. I notice zero difference in towing or weight transfer. I suppose someone could crunch some numbers and come up with some weight amount that gets moved around, but after going through the scales my front has been consistently 4800-4900lbs for the last 4 seasons when towing regardless of where the pin is located.
As far as clearance goes, well since I have LB and a standard 8'W 5er I don't worry about.

[Lantley]

Kennedycamper wrote:
You give the fifth wheel no leverage on the rear axle if the pin is in front of the axle. So you have more stability.

Correct . In general the idea is to not reduce the weight on the front axle by putting excess weight on the rear axle.
You do not want a see / saw effect by placing excess weight on the rear and thus raising the front.
By placing the hitch 2" forward you reduce the likelihood of reducing front axle weight or lifting the front wheels off the ground!

[Kennedycamper]

You give the fifth wheel no leverage on the rear axle if the pin is in front of the axle. So you have more stability.