Determining kingpin weight?

At a CAT scale with multiple scales:
http://learntorv.com/how-to-weigh-a-fifth-wheel-camper-at-cat-scales/

Once you have weigh slips, you can then use this calculator:
http://www.towingplanner.com/ActualWeights/FifthWheelCatScales

At a single-scale location:
http://learntorv.com/how-to-weigh-a-fifth-wheel-camper-on-a-single-scale/

For scale weight information this reference has great charts. Starts in chapter #4 page #55.

Click Here!

While we are on the subject of weighing, someone mentioned an easy way to check your camper weight at a public scale, on your first weigh, weigh the truck and camper together. On your second pass (leaving the truck/camper as is) all you have to do is unlock the hitch and raise the landing gear until the hitch isnt contacting the plate anymore. I'm assuming until you can see daylight between them.

The second weigh will show a difference, and thats the camper weight?

I'll bet I'm missing something here.....

Ron W

wilber1 wrote:
If you really mean pin weight, the difference between the weight of the truck hooked and unhooked will be the pin weight. Hitch location has nothing to do with it, the pin is on the trailer and will be the same wherever you put it.. Weight on the rear axle is something else but for practical purposes, I would consider it the same.

YES...total weight of truck/trailer combo minus total weight of truck is pin weight of trailer

Pin weight distribution when hitched is total weight increase on both truck axles...which is affected by hitch placement in truck bed

Forward of, on or behind center line of rear axle.
With mu hitch 2" forward of center line....150# is added to front axle weight along with the added weight to rear axle

If you really mean pin weight, the difference between the weight of the truck hooked and unhooked will be the pin weight. Hitch location has nothing to do with it, the pin is on the trailer and will be the same wherever you put it.. Weight on the rear axle is something else but for practical purposes, I would consider it the same.

The weight on the jacks should be fairly close to pin weight, but a little heavier than the weight at the pin. If you visualize moving the jacks toward the rear five feet it is easy to see that the farther back they are the more weight on them. If the jacks were moved back to the center of the front to back weight, then most all the weight would be on the jacks. The more the overhang in the front of the jacks, the more the lever effect.

Ahh..ok I'm getting it! That makes total sense. I'm thinking that 2 inches forward is not going to make much difference but that the rear axle weight loaded and then unloaded would be the difference and that would be your king pin weight. Great... thank you for the education!

Actually weight of trucks F/R axles with 5th wheel hitched MINUS weight of trucks F/R axles w/o 5th wheel will be the pin weight of 5th wheel

Depends on 5th wheel hitch placement in truck bed and how truck suspension transfers weight

My Front axle gains 150# and Rear axle gains 2980# for a total of 3130# pin weight
Hitch is 2" forward of rear axle center line (as per hitch mfg. installation instructions)

rhagfo wrote:
Easiest way it to weigh the truck 5er combo at each axle, the drop 5er and reweigh just the truck, difference between the two weights is king pin weight.

Actually the difference between the trucks rear axle weight is the weight of kingpin/pin/hitch. Just the difference between the 2 weights with and w/o 5er is weight of 5er/truck themselves.

This is going to be a ignorant question but...weight for it...LOL!! Seriously....if you weigh your 5th wheel at the front landing gear, will this give you a rough idea of the kingpin weight? I know this is all about geometry and leverage but since the kingpin is fairly close to the landing gear I thought it would be close or maybe a little lighter?

The best determination of weight would be at the scales. However, as an estimate the landing gear's weight would be close to the pin weight.