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KKELLER14K's avatar
KKELLER14K
Explorer II
Oct 25, 2016

5th wheel hitch position in the bed

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?

30 Replies

  • I think I'm going with the trailer pin weight up front as far forward in the bed as I can get and enough to clear the cab as it seems that the weight forward of the rear axels will add some weight to the front axel, not much but, simple as it may seem, it as a whole, the balance of the tow rig seems to be the the issue also. I know that the weight distribution of the trailer itself on the tongue has it limits. Geometrically does it make sense? I have carried as much as 5000+ in the bed with this truck and as to Kingpin weight, this is not my biggest concern because it will never be that heavy. Over all it is stability that I am looking for. I have those 4 tires in the back of that truck that makes a difference, I can't see why it would not be but the position of the hitch head is again my concern. I understand that a light pin weight on the trailer is not good either as if you loaded heavy in the rear of the trailer. So the overall weight of the tow rig should have how much percentage of weight on the pin and where in position inside of the bed of the truck? That is my question. Example: so I have a toy hauler VS. a regular domestic version. If I'm hauling toys in the rear which is a lot heavier.... weight distribution changes right? I'm just trying to understand it all and not trying to be a pain in the butt...this is new to me and I need the real world experience to tell me I'm crazy out of my mind to overthink it but no question is a stupid question only ignorant mistakes can be avoided.. so forgive me for not knowing...any help...helps.
  • Rails are installed and that was not an issue at all...actually easy for me install was a breeze...Again, what I want is advice on the head placement...I get level and side rail clearance of the bed but the forward and aft issue was more a concern....and I get the cab clearance...I just want to know from the professionals here what they know about adjusting the head position correctly....and what is the effect of going on centerline vs. aft or forward....I mean I have the Dually but what is a correct spot for the head of the hitch?
  • if its a longbed the back rail sits at 28 5/16 if its a shortbed the rear rail sits at 26 5/16 from the back edge of the bed
  • 'Chucking' is for/aft movement of 5th wheel ....sway rarely is an issue with 5th wheel unless heavy winds then that is just getting blown around.
    Chucking can be due to pin weight too light (low % of trailers GVWR), trailer braking too soon/too aggressive and hitch placement (king pin)
    Forward of axle center will result in better towing

    Specific instructions for rail placement for your year/brand/model of truck should be the ones followed.
    I know different mfgs have different instructions but they are based on their rails and their hitches

    Use the B&W fixed rail installation instructions

    Here is a 'article' about placement-----LINK
  • So a little forward adds some stability? OK Chucking is the front to back banging around tendency of the trailer? Have not heard this term yet.. sorry I'm learning. My truck is an 02. MMM...my install of the rail kit to my understanding only mentions that the centerline of the Kingpins' base has to be 2 inches forward of center in my bed as to clear the bed supports (sills), not to where the hitch Kingpin head should be or could be... a B & W has many ways to adjust the head position (up, down ,forward, aft)...this is why I ask these questions. IS it just so as your trailer can clear the cab and the head position doesn't matter? As I read all of the install instructions of bed rails for different trucks, it seams to me it has to do with clearances of the base rails to sills of the bed not the Kingpin head position on the base of the hitch. It is all over the map as to measurements of the base. So now I am confused.
  • Old-Biscuit wrote:
    5th wheel hitch can be installed forward/centered/aft of trucks rear axle.

    Mine is 2" forward as per mfg. installation instructions.

    Little weight gets transferred to front axle using a 5th wheel hitch with it forward of center line.

    for best towing and less chucking this is the correct answer
  • 5th wheel hitch can be installed forward/centered/aft of trucks rear axle.

    Mine is 2" forward as per mfg. installation instructions.

    Little weight gets transferred to front axle using a 5th wheel hitch with it forward of center line.
  • To add another question...if your able to have the Kingpin forward of center without hitting the cab, does it add more weight to the front axle and in turn take more load off the rear axle? Oh, BTW I'm talking about DRW Dodge with a B & W with a fixed rail system but you have a lot of adjustment so if anyone wanted to know what the tow vehicle and hitch was.
  • Centered over the rear axle is best. Some short beds are just behind, but that can make for poor handling.

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