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Something I don't understand about weights and capacities


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Looking at the specs on some 5th wheels, something about the weight capacities doesn't add up. I'll try to explain...


The example 5th wheel has a shipping weight of 13,140. It has an indicated carrying capacity of 3745. Am I wrong to add these two to reach a GVWR of 16,885?


Assuming that's correct, there are two axels rated at 7000 apiece. This would seem to suggest a max carrying capacity of 14,000. Is that right?


If so, this is a trailer with a GVWR of 16,885 and an axel rating of that is 2885 short of the GVWR. Am I missing something?

"A good engineer is always a wee bit conservative, at least on paper." -Scotty, "Star Trek: The Next Generation: Relics"


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You're on the right track. One thing to consider is the weight that will be on the hitch. Subtract the hitch weight from the total and you should be under 14k. I had the same question on our 5th wheel when we went from a MH to the trailer.


Good question.

The richest are not those who have the most, but those who need the least.

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The general rule is 20-25% of the total weight on the hitch, thus on the tow vehicle rather than the fiver axles. 20% of your 16,885 = 3,377. Thus 13,508 on your two 7k axles.


My fiver for example has a GVWR of 20k and two 9k axles, thus I need at least 2k pin weight. Mine lands at 21% so I have 4,200 lbs pin weight - plenty of leeway.


This is the reason we are always weighing our individual rigs so we can figure out exactly where the weight is sitting.

Dennis & Nancy
Tucson, AZ in winter, on the road in summer.

1999 Volvo 610 "Bud" 425 HP Volvo, Super 10 spd.
2005 Mountain Aire 35 BLKS
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(Replaced '05 smart first loaded in '06

and '11 smart that gave it's life to save me!)
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Don't worry.. you're not alone. Weight ratings can be confusing.


To start with, the dry/shipping weight is simply an estimate and a rigs actual weight generally varies.. as does the cargo capacity.. so those "published" weights are really kind of worthless in real life but are there to "get you in the ball park". The number you really want is the 5r's GVWR. From there you would get an actual weight of your 5r at the scales to be entirely accurate. It's generally best to have it loaded out as you would for a trip. From there you would subtract that weight from the GVWR to determine what additional cargo capacity you have remaining.


The axle ratings are for "under tow".. not necessarily sitting under a static load, however, not all of your 5r's actual weight is being carried only on the axles. A portion of total weight will be carried on the hitch and should put you under the combined axle ratings.


One addition point to note is that weight distribution of your rig must be closely adjusted.. as well as setting your 5r to tow level.. so that one axle and tire set is not loaded more heavily than the other.

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We find most units weighed when loaded for full time or snowbird travel run pretty close to GVWR on the sticker. Or maybe a tad or more... Over.


Forget dry or empty weights as mentioned. It's the GVWR you want to use.


Of course once your loaded and ready weigh your unit. Preferable by individual wheel.


All the advise mentioned in the posts are right on.

Bill and Joan and 3 Collie pups

2001 Volvo VNL 770 "The Doghouse" Singled short, "ET" hItch VED12 465HP Gen 1 Autoshift 3.58 ratio  2005 Mobile Suite 38RL3  2011 Smart Passion loaded piggybacK

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Don't forget to include the weight of fresh water and black & gray water from the carrying capacity. Granted you may not always travel with full water & holding tanks, but there is a huge amount potential weight there. Water is ~8.3 pounds per gallon. 70 gallons of water is around 560 pounds of that carrying capacity.

Al & Sharon
2006 Winnebago Journey 36G 
2020 Chevy Colorado Toad
San Antonio, TX


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I have a Jayco Featherweight Trailer that I just bought used. GAWR = 3300 pounds. Individual tires are rated at 1710 lbs each. Hitch weight is 415 lbs. GVWR is 3500. Is my tire capacity sufficient? It doesn't add up to the GVWR of 3500 lbs but it is in excess of the GAWR of 3300 (1710x2=3420).

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Because your tire capacity exceeds the rated GAWR, they're sufficient. Your GAWR plus the tongue weight rating of 415# exceeds the rated GVWR, and the tires need not account for that.


Tongue/hitch weight on a travel trailer works just as the pin weight does in the above examples for fifth wheel trailers -- it's covered by the GVWR, but doesn't have to be accounted for in the GAWRs, of which the tires are a part -- since that portion of the trailer's weight is being transferred to the tow vehicle.



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