Ran across a scale today

[Chad Heiser]

So, I took the new DRV out for a shake down run and a quick over night stay.  I wanted to test the new solar (I will report on this in a different thread when I have a little more data) and I wanted to get my actual weights now that the 5er is all set up.  I pulled into a TA and filled the truck up with fuel.  This was its own problem.  The clerk who tried to help me first ran two of my credit cards multiple times and somehow got them each declined multiple times.  She was adamant it was a problem with my cards.  I went to a different clerk and she was able to get my card to work on the first try.  Not sure what the issue was, but it resulted in several calls from both my credit card companies making sure there was no fraud involved (at least that was good).

Once the truck was full of fuel and carrying my normal load (less my DW), I ran the complete rig over the CAT scale (it's not individual wheel weights, but it's the best I can do for now).  The trailer is fully outfitted now with my large (and heavy) battery bank (1040 amp hours), Onan 6500 watt commercial generator, 1410 watts of solar, two inverters, and all of our "stuff."  I had full propane (two 40 lb bottles) and full water (approximately 100 gallons).  Basically it is set up as we would travel.  Typically I don't travel with a full freshwater tank (unless I absolutely need to), but I have only minimal food and clothes in the trailer for this overnight trip so I'll call that a wash (a typical load would have more food and clothes, but less than half a tank of water - just in case).

Combined weight was 39920 lbs.

Truck weight was 18520 lbs.

5th wheel weight was 21400 lbs.  

The 5th wheel GVWR is 21500 lbs., so I am close but under weight.

Truck front axle with trailer attached was 9940 lbs. Truck front axle without trailer attached was 10720 lbs.  So I am unloading my front axle by 780 lbs. when the trailer is attached, but I am well under my 12500 lb. axle rating either way.

Truck rear axle with trailer attached was 13100 lbs.  Truck rear axle without trailer attached was 7800 lbs.  Also well under the axle rating.

Trailer axles were 16880 lbs.  Well under the 18000 lb. rating of my two 9000 lb. MorRyde IS and the 19220 lb. combined rating of my Goodyear G114 tires.

The trailer pin weight was 4520 lbs.  That is 21% of the total trailer weight, right in the sweet spot between 20% and 25%.

All in all I am happy with everything.  I was afraid my trailer was going to be over weight with all the stuff I added, but I came in just under (happy days  ).

[Radar274]

Nice Numbers.  Thanks for all the help, sent my build sheet in yesterday after factory visit. 

Have a safe trip,

Bob

[DJohns]

Am I wrong but rear axle loaded 13100 minus 7800 rear axle unloaded be more than 4520 pin weight? More like 5300 pounds or am I doing something wrong.

[rickeieio]

20 minutes ago, Dan Johnson said:

Am I wrong but rear axle loaded 13100 minus 7800 rear axle unloaded be more than 4520 pin weight? More like 5300 pounds or am I doing something wrong.

I'm only on my third cup of coffee, so won't attempt the cipher'n, but the difference is caused by the pin being behind the axle, thus the lighter front axle weight when hooked up.

[Tahoe Shark]

Chad,

wouldn't pin weight be 5300 as Dan suggested? If not you are way under my pin weight and I don't have the gen or 300 extra ,bs of batteries.

[Nigel]

I think Chad has is right.  The actual pin weight of the trailer is 4520 add to that the 780 that came off the front axle and that is where you get the 5300 load on the rear axle.  If the hitch was moved further back you would get more weight on the rear axle, less on the front but the trailer pin weight hasn't changed.

Nigel

[Tahoe Shark]

Not saying I'm wrong or right, but when I had RVSEF weigh my unit they calculated our pin weight by weighing our rear axle weight loaded with trailer and subtracted the unhooked truck rear axle weight. I will let the experts here correct me but it seems to me the transference of the 780lbs front to rear on Chads truck has nothing to do with actual pin weight. Axle weight yes but not pin. Please set me straight.

[Ronbo]

Weigh the truck by itself, both axles. Then get the truck weight hooked to rv, both axles. The difference is the pin weight. Get the axle weights of the rv. Add the pin weight. That is the total weight of your rv.

[Big5er]

Ronbo is right. The truck unhitched is 10720+7800=18520
                                         hitched it is  9940+13100=23040

23040 (hitched) - 18520 (unhitched) = 4520 additional, which can only come from the weight of the tongue.

[Ronbo]

Thanks Big5er, I didn't want to do the math. 

[Big5er]

Just now, Ronbo said:

Thanks Big5er, I didn't want to do the math. 

No problem Ron. That's the kinda math I do daily. I have more spreadsheets and apps just for those numbers than I can count. 
Maybe I need a spreadsheet for the spreadsheets?? 

[Chad Heiser]

Thanks Big5er, you beat me to it.  Yes my pin weight is 4520 lbs.

At first I had the same question, "How do I factor in the weight removed from the front axle?"  Then I sat down and did the actual math and it all made sense.   Total combined weight of truck and 5er is 39920 lbs.  Total weight of truck without trailer is 18520 lbs.  This means the trailer has to weigh 21400 lbs.

39920 - 18520 = 21400

Axle weight of trailer is 16880 lbs.  Subtract this from the trailer total weight and that is the pin weight.

21400 - 16880 = 4520

While there is a weight transfer from the front to rear axle on the truck when the 5er is hooked up, it is just that - a transfer.  The truck weighs what it weighs and the trailer weighs what it weighs.  

[TreyandSusan]

Agreed (Chad, Ron, Phil). Just to be clear RVSEF calculates pin weight this way, too. (Not as mentioned above)

 

[billr]

We do it the same way. Total truck with and without   Diff is pin.

nice numbers to start with. 

[Tahoe Shark]

55 minutes ago, TreyandSusan said:

Agreed (Chad, Ron, Phil). Just to be clear RVSEF calculates pin weight this way, too. (Not as mentioned above)

 

Thanks for clearing this up for me and giving me the formula. I had a great time getting weighed by Trey & Susan and made a lot of packing changes when I got home. As it turns out with my weights the way I did it returns almost the same pin weight. It must be a coincidence with that particular combination. That will teach me to double check all of my figures and formulas.

Chad,

now we have to figure out why my trailer pin is so much heavier than yours. Maybe mine is just longer in the front because of the larger basement shifting more weight on the pin.

Anyway thanks everyone for the lesson.

[Chad Heiser]

4 hours ago, Tahoe Shark said:

Chad,

now we have to figure out why my trailer pin is so much heavier than yours. Maybe mine is just longer in the front because of the larger basement shifting more weight on the pin.

Anyway thanks everyone for the lesson.

I'm not sure what the differences would be.  What was your pin weight?

Your trailer is built on the same length frame as mine, but it has a bigger basement (by at least a foot and a half wider).  There could be more steel in that box to support the larger basement.  I think your platform for the bedroom and bathroom area is larger than mine as well (which is how you get the bigger basement).  There could be more weight in the way that is constructed as well.  I have more weight in batteries and the generator, plus I had extra steel put in the basement floor to help support this weight.  I would think these areas would somewhat cancel each other out between our trailers, but who knows.  Your floor plan is a stretched version of what it was originally supposed to be. I don't think this would affect the axle placement, but maybe your axles are slightly farther back than mine, resulting in more pin weight?

It could just come down to what we have loaded in the trailer.  We have very little in the bedroom right now.  I also don't really have any heavy items in my basement (besides my batteries).  All I have down there is my Weber Q grill (with stand), some chairs, a couple of folding plastic tables, my folding ladder and a small easy up.  Jen says I haul too much "stuff" but really I don't take a lot.  My floor plan has some extra storage compartments along the frame that allowed me to move all my miscellaneous hoses and electrical connections out of the basement also, but that isn't really all that much weight either.

[DJohns]

Thanks everyone. This explanes  how NH got my pin weight. They weighed my truck and trailer then we went back to weight truck only. I figured the pin weight they wrote down was a engineered weight.

[Tahoe Shark]

10 hours ago, Chad Heiser said:

I'm not sure what the differences would be.  What was your pin weight?

At the time of the weighing it was 4950. I really need to do it again after the solar install and removing some weight. We are going out next weekend and I am going to measure from the front of the tires to the generator doors on the vertical and then to the pin. I can't imagine they changed the cap but maybe the axle to front spacing. It will be interesting to see. I will let you know so we can compare like to like.

[NoDirectionHome]

You guys need to compare trailer wheelbases from pin to center of axles.  Nothing makes more of a difference in balance.

[Jack Mayer]

No Direction has the answer. If the upper deck is different (larger) then it will add weight to the pin. It does not take much. Adding just 18" to our upper deck increased the pin weight on our NH by about 1000 lbs. I also added some weight in the larger basement. 

Chad, nice weights. You did not unload the front much. I did not figure the ratio front/rear yet but I will and add it to my numbers I'm keeping on various rigs.