Weight question

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rubysamm

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I Know I know you all have seen and answered this question tons of times.  I also know how important it is to get it right.  I simply get a bit confused with "maximum payload" " GVWR" "axle ratio" etc. and so forth.
So here it is.
If the 5TH-WHEEL TOWING vehicle specs Maximum Loaded Trailer Weight (lbs) =14,700  -- max pay load 3200  --  gvwr 9200  -- axle ratio 12500

and the 5th wheel spec is GVWR 11,620  -- Ship weight is 7,850  --  Axle weight -- 6,390  -- Hitch weight 1,460

Would you say it is a compatible tow vehicle? Have I given enough info to answer this question correctly?
Thanks for your help
Lori
 

Karl

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Lori,

If you click on the "Library" button above, then select "Glossary of RV terms" in the "Resources Menu" section on the left of the screen, you'll be able to find concise definitions for all those terms. Once you have familiarized yourself with them and have a specific question about your setup, please feel free to ask away. :D
 

Gary RV_Wizard

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Chances are your tow vehicle is ok for that load, but you really need to familiarize yourself with the terms. They are described in our Glossary, which you can find from the rvforum.net home page.

Towing a fifth wheel, the main concerns are the difference between the actual, loaded tow vehic;le weight and the tow vehicle's GCWR (not GVWR). You can safely tow the difference between those two numbers as long as the trailer's hitch weight does not exceed the carrying capacity (payload of the truck).  The trailer you are looking at will probably have about a 2000 lb hitch weight once it is loaded for the road (not the 1460 in the trailer specs - that's an unloaded weight), so its probably OK.  However, the tow vehicle's max payload has to cover everything you put in/on the truck, including passengers and gear, so weigh it loaded for the road, not as it came from the factory.

Read the Glossary (LOTS of good info there) and then check back here
 

md3500

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Apr 24, 2006
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Lori,

I also get confused reading the terms, which also have different terms on other sites or in Canada.? RV Roamer is correct in that you need to know what your Gross Combined Vehicle Weight Ratio (GCWR) which is the total weight of the Tow vehicle and the Trailer. So if the total weight of your trailer is 11620 + 9200 total weight of your tow vehicle = 20820 GCWR.? So if your tow vehicle GCWR is rated at more than 21000 than you're okay.
 

md3500

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My question for thiose more informed is is the hitch/pin wight doubled counted when determining Gross weight?  For example, BTW this is not in the glossary, nor can I find this specific example anywhere,  Lets say:
Gross Vehicle Weght is = 11400 (Vehicle weight 7450, Payload capacity 3950)
Towing Vehicle Gross Towing Capacity = 16700
Max Payload = 3950
Gross Combined Vehicle Weight Ratio (GCWR) = 23000
Fifth Wheel Gross Vehicle Weight = 15500
Fifth Wheel Hitch Weight = 2750

Actual GCWR if both truck and trailer are individually at the max weight = 26900 (which would be over weight, unless there was no other payload weight.

So here's my question;  does the hitch weight get counted twice?  Once as weight of trailer and  then again payload weight? Since the truck should be carrying ~20% of the trailer weight  In my example above or does it really matter as long as you account for the weight?
 

davidsimmonds

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Correct me if I am wrong, but the hitch weight is a metric of the force exhibited into the bed of the truck. You add the value to the total cargo capacity of the tow vehicle. You truck has a Max Payload of 3950, so take away the hitch weight and you have 1200. Now take away the weight of the fuel, passengers, and any cargo that you put into the truck. The 1200 lbs remaining will quickly go down. As noted before, the hitch weight is calculated on an empty trailer, so the 2750 weight could be larger.
 

Gary RV_Wizard

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So here's my question;  does the hitch weight get counted twice?  Once as weight of trailer and  then again payload weight? Since the truck should be carrying ~20% of the trailer weight  In my example above or does it really matter as long as you account for the weight?

No, you don't count it twice when determining the GCW for the entire rig. Either weigh the truck & trailer together at one time to get the total or weigh them separately, in which case the hitch weight is not on th etruck when you weigh it.

But when comparing the truck's actual weight to its GVWR, you have to add in the hitch weight, since it is carried on the truck as part of its payload.

The confusing area is with the trailer's GVWR.  The hitch weight is not actually carried by the trailer suspension and you will notice that the axles on most fifth wheels do not have enough capacity for the entire GVWR of the trailer. That's because the hitch (pin) weight in on the tow vehicle when traveling and on the landing gear when parked, so the trailer axles never have to carry that portion of the load.  But that's not relevant to much of anything except computing trailer tire and axle requirements.
 

md3500

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RV Roamer said:
No, you don't count it twice when determining the GCW for the entire rig. Either weigh the truck & trailer together at one time to get the total or weigh them separately, in which case the hitch weight is not on th etruck when you weigh it.

But when comparing the truck's actual weight to its GVWR, you have to add in the hitch weight, since it is carried on the truck as part of its payload.

The confusing area is with the trailer's GVWR.? The hitch weight is not actually carried by the trailer suspension and you will notice that the axles on most fifth wheels do not have enough capacity for the entire GVWR of the trailer. That's because the hitch (pin) weight in on the tow vehicle when traveling and on the landing gear when parked, so the trailer axles never have to carry that portion of the load.? But that's not relevant to much of anything except computing trailer tire and axle requirements.

Gary,  Thanks for the reply.  If I understand it correctly then, the weight of the trailer is not fully carried by the trailer axles, so you have to account for the weght/force that the trailer is putting on the tow vehicle.  Then as a rule of thumb (unless you actually weigh it) the trailer hitch weight/force that the trailer puts on the Tow vehicle is ~20% of the weight of the trailer.  This weight needs to be accounted for as part of the Tow vehicle's payload or Gross Vehicle Weight.   

(4x4 crew cab GVW) 11400-6552 (Curb Weight)=4848 (Available Payload before Trailer)    4848-3100 (Trailer Hitch Weight 20% of 15500 Trailer GVWR) = 1748 (Remaining Payload available after Trailer)

6552+1748=8300+15500=23300 GCWR which is 300lbs more than the the tow vehicle is rated for.  So if this was my situation, I would need to make sure I did not max out the trailer weight and/or reduce the truck weight.
 

Gary RV_Wizard

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No.  You have double counted the hitch(pin) weight in your GCW calculation.  Nothing should ever get counted twice.

You add in the hitch (pin) weight when evaluating the the truck's GVW because it is part of the load that must be covered by the truck's GVWR, but do not include it in both the truck and trailer portions when you do GCW.  Note that if you actually weighed the entire rig, it wouldn't  weigh twice.

The 20-25% hitch weight factor applies only to fifth wheels. Any trailer on a conventional hitch, whether weight carrying or weight distributing type, will be about 12-15%.

 

Bill_Frisbee

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I do not know if it helps or confuses the discussion but I thought I would provide the specifics of my situation. If it helps clarify, great. If not, ignore!

According to the scales at our local Recycling Centre, our TV weighs approximately 7,900 lbs when we are on board along with our clothes, a full load of diesel, etc. but WITHOUT the 5er attached. The 5er has a GVWR of 13,975 lbs.  So if the RV were loaded to its max (which it NEVER is), my GCWR (the total weight I am actually moving down the road) would be 7,900 lbs + 13,975 lbs = 21,875 lbs, well within the truck's 23,000 lbs limit.

In my case (and the case of many people hauling large 5ers), a far greater concern is the truck's GVWR of 9,900 lbs. Given that the truck weighs 7,900 lbs when loaded for the road, I have 2,000 lbs left for the pin weight if I am to stay within the GVWR. The "out the factory door" pin weight on my 5er is listed as either 1,770 lbs. or 1,975 lbs, depending on which set of specs you look at. I assume the larger number. The fact that I am carrying two batteries and two 30 lb. LP tanks immediately eliminates any possibility that my pin weight is 2,000 lbs or less. So I am overweight.

Because of this situation, I do not carry anything in the 5er (and especially in the "basement") that is not absolutely necessary. The total weight of everything I carry in the basement (water hoses, shore power line, etc) is less than 100 lbs. The unit came equipped with one of those "sliding trays" in the basement. It weighs 85 lbs. I got rid of it. I do not carry a generator in the front hatch. Because we do not do any drycamping or boondocking at this point, I am seriously considering removing one of the batteries. In short, I am doing everything I can to keep my pin weight as close to 2,000 lbs as possible.

That having been said, the Gross Axle Weight Ratings (GAWR) on my truck are 5,200 lbs in the front and 6,200 lbs in the rear. The combined GAWR for the truck is thus 11,400 lbs, 1,500 lbs greater than the GVWR. The tires on the rear of my truck are rated to carry 3,100 lbs/tire @ 75 psi. Note that the combined weight-carrying capacity of the tires is precisely the GAWR of the rear axle.

Finally, the specs on my truck state that, when unloaded, the distribution of weight in the truck is 60% on the front axle and 40% on the rear axle. Using that as an approximation, that would indicate that 40% of the 7,900 lbs loaded weight (stated above) is being carried by the rear. Thus, .4 x 7,900 = 3,160 lbs. In order to remain within the 6,200 lbs GAWR of the rear axle, my pin weight must thus be 6,200 - 3,160 = 3,040 lbs. I am absolutely confident that I am not even remotely close to a pin weight of 3,000 lbs.

Without any question, my truck WILL handle the weight (both the pin weight and the total weight) of my 5er. The issue, however, is one which many members of this forum discuss frequently ... can your truck handle the weight SAFELY and CONTROL the weight in an emergency situation on the highway? This question explains my paranoia about removing every lb of unnecessary weight, my absolute  refusal to travel at speeds in excess of 100 km/hour (62 mph), and my willingness to spend (probably over-spend) whatever money is necessary to ensure myself that both my truck and my RV (especially brakes and tires) are in the very best mechanical and operating condition possible at all times. I have had one emergency situation on a high-speed, multi-lane highway within a densly-populated urban area. It actually occurred during the road test for my Class A driver's license! The truck and the RV stopped quickly, in a totally straight line, without locking the brakes, and with no damage of any kind. That convinced me that my paranoias are well-directed!

Bill
   

 

Bill_Frisbee

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Guelph, Ontario
Thanks, Gary. Lessons from the "school of experience"!

I also wanted to add that our choice of tow vehicle was a compromise. The truck is my daily driver, we live in a city with numerous narrow streets and old parking lots with small spaces, and we deal with snow in the winter. In addition, our travels with the 5er at this point are restricted to locations within a 1-day drive from home. We are still working full-time and prefer not to spend our limited vacation time on the road if possible. All of this led to our choice of a 1-ton pickup with Single Rear Wheels (SRW), a short bed, and a 9,900 lb GVWR. Once we retire, however, we intend to do more long distance touring and avoiding the snow in the winter. I anticipate that we will trade our current pickup in for a long-bed dually with its significantly greater weight-carrying capacity at that time. We are also waiting to see what is going to happen with regard to diesel engines, diesel fuel, etc in the next few years. It sounds like significant changes are likely.

Putting together the right combination of TV and RV can be extremely difficult, especially if an individual is inexperienced in these matters. RV manufacturers routinely publish figures that significantly understate the actual weights of their units when in use by normal people. Truck manufacturers routinely overstate the actual weight-carrying capacity of their vehicles, again when being used by normal people to haul RVs. Salespeople for fifth wheels and the trucks we buy to haul them NEVER explain these realities ... just like they never tell customers (even when asked directly) that in order to legally tow a large 5er in most jurisdictions (in Ontario, towing any trailer in excess of 10,000 lbs measured by GVWR) requires people to obtain a special license.

Online forums in which issues such as this are discussed are invaluable. Unfortunately, too many people discover the forums after they have made their mistakes rather than before.



Bill
 
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