Measureing Pin Weight on a Gooseneck

[WM-300]

I would like to measure my Pin weight on my Gooseneck trailer with my different trucks on the trailer. I dont have a scale that goes high enough to directly measure the oin weight. But, I remember many years ago in High School Physics about a method using bathroom scales, a length of 4x4 and a pipe as a pivot point. Your weight goes at a point on the 4x4 and a conversion factor is used with the scale weight for the real weight.



I was sleeping that day in high school and forgot how it was done. Any one know ?? or how do you measure your pin weight.



Thanks

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[klenger]

Two weighings at a CAT scale. One with the truck only, and one with the trailer attached. Then subtract. Cost is about $8 per weighing. Go to http://www.catscale.com for locations.

 

[Gary - K7GLD]

My poor grades in Physics class may let me down, but I think a 5 foot (for instance) length of 4x4, with a stationary support at one end, and carefully applying downforce at the 1 foot marker from THAT end, will weigh out at a 5:1 ratio at the far end - so if the scale indicated 100 lbs, pin weight would be 500 lbs. , etc...



(here come the flames... )

 

[Gary - K7GLD]

"Two weighings at a CAT scale. One with the truck only, and one with the trailer attached. Then subtract. Cost is about $8 per weighing. Go to http://www.catscale.com for locations. "



Well JEEZE Ken - ANYONE can go to a *scale* and get the weight - we're trying to do it the cheapskate BACKYARD way!

 

[WM-300]

There are no Cat or other truck scales up here in the Mountains. nned the backyard way.



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[Gary - K7GLD]

Actually, I've never specifically weighed my hitch weight either - I know it's spec'd at 950 lbs dry - but I've added enough stuff to channge that - might give it a try myself just for grins...

 

[Gary - K7GLD]

Well, having a little extra time on my hands, I decided to try weighing my 24 foot Kit 5er using the method I suggested above. I used an 8 foot 4x4, resting one end on a steady-rest, placed the 5er pin in exactly 12 inches - and the loading point of the bathroom scales out at the 6 foot mark:



THEN, after zeroing the scale, dropped the weight of the 5er onto the 4x4, and THIS is the result:



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196 pounds, times the 6 foot overall length of the 4x4 gives us 1176 lbs. The manufacturers claimed dry pin weight for my trailer is 950 pounds - but I have added a pair of large and heavy golf car batteries up at the front of the 5er, and have 2 full propane tanks there as well - I also have added an air conditioner and full length awning, plus a few other items kept packed inside the trailer for travel - so that pretty well accounts for an added 225 pounds or so - and I also acknowledge that this test was done on slightly uneven ground, so actual weight could be slightly off - but certainly close enough for this purpose...

 

[Beast2B]

Hey Gary, maybe you could adjust the length from the pivot point to the hitch pin or the hitch pin to the scale and verify the relationship of the distances to the ratio... I'm at work hardly working thought I might help the science class experiment!

 

[klenger]

Gary's process looks correct to me, 'cept for the angle of the timber.

 

[Gary - K7GLD]

The beam angle is more level than it appears - the camera wasn't precisely level...



Isn't intended as laboratory accurate, but only to demonstrate the principle - and sure, the specific lengths of the beam and pivot point can easily be adjusted for specific weight ranges - a heavier tongue weight might need a 10 foot beam, or a lighter one might get by with a shorter one - it's just simple math...

 

[klenger]

In looking at Gary's example, it looks like it would be a good idea to keep the landing gear as close to the ground as possible, just in case ...



Rather than elevating the scale and beam, it seems like it might be safer to keep the scale and beam at ground level and then use a short beam between the king pin and horiz. beam.

 

[Gary - K7GLD]

"Rather than elevating the scale and beam, it seems like it might be safer to keep the scale and beam at ground level and then use a short beam between the king pin and horiz. beam. "



YUP - ya just use whatever your source allows - I happened to have the heavy duty supports, so it worked out fine for me - and yes, by ALL means, lift the trailer support legs no more than needed to obtain full loading on the scale, for safety's sake!

 

[WM-300]

Thanks Gary;

I will do it on Friday when I load my Trailer. I will post the results



Thank You

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[PatrickCampbell]

If you really just want to know about the trailer and want to only pay $8 not $16, you can detach the trailer while on the scale. if it's not busy, nobody will care. Wherever there are interstates, there are scales... where in the Adirondacks are you? We used to go up to Keene Valley a lot and hike up Cascade and Porter. . really beautiful country up there.

 

[Gary - K7GLD]

3 problems weighing for pin weight:



1. Hooking up the trailer and GETTING it to the nearest scale - then unhitching it to weigh, then re-hitching.



2. Weighing only for pin weight by unhitching usually places the actual pin at the extreme end of the scale, whuch MIGHT affect weight accuracy, depending on the scale - plus the need for some sort of support for the pin by itself.



3, Trying to weight a 1000 lb pin weight on a 50 ton scale (or whatever it's upper limit is) might be like trying to get accurate weight of a letter on a bathroom scale.



Maybe someone here has first hand info on some of the above?



It only took me about 10 minutes to weigh mine and take photos using the method above, and I didn;t have to move a thing...

 

[WM-300]

Patrick.

Schroon Lake, we also hike the 46 and are licensed Guides



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[WM-300]

Using Gary's procedure today, I was able to load my truck and mark the deck for repeated loadings. I wanted 15% pin weight of 1521. I was able to easily find 1500 on the scales. Now to load my otehr truck and also mark the bed. Thanks Gary



Wm-300

KS2K

 

[Tony T.]

Gary did you calibrate your scales before the experiment for a precise measure of weight. I have a similar set an they are exactly 10lbs off.