King pin weight

mikec557 · 07-22-2018, 07:01 PM

We're looking at upgrading our TV now and anticipate upgrading from our TT to a 5th wheel in the next year or so.

In anticipating the weight on the rear axle of the new TV, I thought I would ask...

How much has your pin weight increased after you loaded your 5W? For instance, if the empty 5W from the factory has a pin weight of 1600 pounds, what is it after your 5W is loaded up with 1500 pounds of stuff? Is there a rule of thumb?

Any thoughts and advice are appreciated.

Mike

mcmeadows1 · 07-22-2018, 07:17 PM

The general rule of thumb is that a loaded 5th wheel’s king pin will exert 20% of the the trailer’s gross vehicle weight. For example, if the trailer weighs a total of 10,000 lbs, the king pin will exert 2,000 lbs.

Obviously, each individual trailer will be different depending upon where cargo (weight) is loaded, in relation to the trailer’s axle(s), and where the fresh water tank is positioned, and if it is empty, full, or somewhere in between. Also, the weight of effluent in the black and grey tanks will also have an affect on the king pin weight.

Frank G · 07-22-2018, 07:21 PM

A better way to do it is look at the GVWR of the 5th wheel, about 22% of that will be pin weight. To be safe add about 1000 lbs for passengers, dogs, hitch and other stuff. Add those two numbers together along with the empty (scaled) truck weight and that number must be lower than the GVWR of the TV as stated on the "B" pillar.

rhagfo · 07-22-2018, 08:41 PM

If you really want to be safe figure 25% of GVWR of the 5er.

mikec557 · 07-22-2018, 09:28 PM

Thanks to everyone. That gives me a rule of thumb I can use.

Mike

NotyetMHCowner · 07-23-2018, 05:12 AM

We are at 27% of our actual weight. Pin weight 3660 with trailer weight around 13400. We do have golf cart batteries, generator and washer dryer all up front so that contributes to our front heavy weight.

KOZKO · 07-23-2018, 12:29 PM

Just to be sure, the manufacturers stated pin weight is with an empty trailer?

**JRTJH** · 07-23-2018, 01:16 PM

Quote:

Originally Posted by KOZKO

Just to be sure, the manufacturers stated pin weight is with an empty trailer?

The brochure or website pin weight is for the empty trailer as it leaves the assembly line, empty propane tanks, no battery and no fluids in any tank. Depending on the model, you'll need to add the weight of the propane (usually 60 pounds for fifth wheels) and about 30 pounds for each battery. Remember that the "website weights" are for a standard build trailer, so if a second A/C is added, if upgraded furniture and/or if other options are added, they will add to the pin weight (if forward of the axles) and possibly reduce the pin weight (if aft of the axles).

fjr vfr · 07-23-2018, 03:24 PM

My Laredo lists pin weight of 1361 lbs. The base weight empty is 7,750 lbs. This comes out to 17.6 %. The total gvwr is 10600 lbs so 17.6 % comes out to be 1861 lbs.
That said I am not going to rely on those figures. I plan on weighing the trailer with the truck and the truck separately. that's the only way to know for sure.
Our trailer is pretty new to us and that's the only reason I haven't done it yet.

fjr vfr · 07-27-2018, 12:20 PM

Quote:

Originally Posted by fjr vfr

My Laredo lists pin weight of 1361 lbs. The base weight empty is 7,750 lbs. This comes out to 17.6 %. The total gvwr is 10600 lbs so 17.6 % comes out to be 1861 lbs.
That said I am not going to rely on those figures. I plan on weighing the trailer with the truck and the truck separately. that's the only way to know for sure.
Our trailer is pretty new to us and that's the only reason I haven't done it yet.

I weighed our Laredo 265rl earlier today. Here are the results. Hitch weight came out to 1,780 lbs, trailer axle weight 7,380 lbs and trailer total 9,160 lbs.
Compare that to the listed weights above. The pin weight comes out to 19.4% of the trailer.
Some more info, trailer was loaded to about 90% of traveling weight. The fridg was empty, no food and most of our clothing not loaded. Most everything else we travel with was in the trailer. Numbers will go up some.

Tbos · 07-23-2018, 04:58 PM

The brochure says 2695 pin weight for my Alpine 3651. Actual is 3260 or about 22% of my loaded 5er weight. I’m glad my 2016 F350 Diesel CC has a cargo capacity of 5601. FYI, I travel with 1/4 fresh water and black and grey tanks empty.
Edit, I was surprised how nice and helpful the folks at the Cat scales were.

mikec557 · 07-23-2018, 05:17 PM

Quote:

Originally Posted by Tbos

... I’m glad my 2016 F350 Diesel CC has a cargo capacity of 5601...

Do you know what your rear axle weighs with the 5W disconnected and the truck more or less empty? That is, how much of the total cargo capacity can the rear axle hold before it reaches its own GAWR?

We're looking at an F350 diesel CC and will of course weight it, but thought I'd ask if you know what yours weighs...

Thanks
Mike

Tbos · 07-28-2018, 06:04 AM

Quote:

Originally Posted by mikec557

Do you know what your rear axle weighs with the 5W disconnected and the truck more or less empty? That is, how much of the total cargo capacity can the rear axle hold before it reaches its own GAWR?

We're looking at an F350 diesel CC and will of course weight it, but thought I'd ask if you know what yours weighs...

Thanks
Mike

Truck GVWR 14000lbs
Rear GAWR 9650lbs
Front GAWR 5600lbs

Actual without 5er
Front 4880lbs
Rear 3800lbs
Gross total 8680lbs

With Alpine 3651RL
Front 4960lbs
Rear 6980lbs
5er axles 11580lbs
Combined gross 23520lbs

mikec557 · 07-28-2018, 06:24 AM

Quote:

Originally Posted by Tbos

Truck GVWR 14000lbs
Rear GAWR 9650lbs
Front GAWR 5600lbs

Actual without 5er
Front 4880lbs
Rear 3800lbs
Gross total 8680lbs

With Alpine 3651RL
Front 4960lbs
Rear 6980lbs
5er axles 11580lbs
Combined gross 23520lbs

Tbos:

That is awesome real world information. Thanks, that answers some of my unknowns.

Mike

labman · 07-25-2018, 05:37 AM

I saw the ultimate tv in Tucson last winter. a F450 lariat 6.7 powerstroke

and it was bulletproofed.

rhagfo · 07-29-2018, 04:22 PM

Quote:

Originally Posted by labman

I saw the ultimate tv in Tucson last winter. a F450 lariat 6.7 powerstroke

and it was bulletproofed.

Well a 6.7 doesn’t have the issues of the 6.0 and 6.4. No reason to bullet proof.

rhagfo · 07-29-2018, 04:29 PM

Quote:

Originally Posted by Tbos

The brochure says 2695 pin weight for my Alpine 3651. Actual is 3260 or about 22% of my loaded 5er weight. I’m glad my 2016 F350 Diesel CC has a cargo capacity of 5601. FYI, I travel with 1/4 fresh water and black and grey tanks empty.
Edit, I was surprised how nice and helpful the folks at the Cat scales were.

I NEVER count on being able to travel with black and grey empty! Spent five days at a horse show with only power and shared water. When we left nearest dump station was 20 miles the wrong direction! We towed it all home over Santiam Pass 4,800’+, always figure worst case!

Tbos · 07-30-2018, 05:04 PM

Quote:

Originally Posted by rhagfo

I NEVER count on being able to travel with black and grey empty! Spent five days at a horse show with only power and shared water. When we left nearest dump station was 20 miles the wrong direction! We towed it all home over Santiam Pass 4,800’+, always figure worst case!

Good point. I usually don’t camp unless I have dump facilities nearby. That is definitely something to take into consideration.

notanlines · 07-30-2018, 05:34 PM

"I'm saying why pay so much?" They are weighing each wheel individually. When weighed like that you get not only an axle by axle weight, but you find out if one axle or wheel is carrying an extraordinary amount of weight. No, I have never done it, but if I had one tire wearing in an odd pattern I might.

NotyetMHCowner · 07-31-2018, 08:17 AM

The good thing about weighing each tire is just as has been stated. If your fridge or something is really heavy for example, that tire may be overloaded even so the axle weight may not be. CAT scales will only show axle weights. Since most manufactures put the least possible capacity tire possible on their rigs, overloaded tires are a real possibility.

My way of thinking is the BARE minimum of truck should be able to handle the GVWR of the trailer, NOT empty weight or "I only load 1000 pounds of stuff". The GVWR only. I would use 25% for pin weight for any extra front loading you might want to do. If your only 20%, then great! You have an extra safe margin. If the trailer is 10k lbs or more, I would up grade the tires. If it came with D then go to E. If it came with E then go to G. I have never understood how someone could spend $30K, $40K, $50K or more and then gripe about $1000 worth of tires to have peace of mind.

My philosophy is the most important things with towing a camper are Tires, Bearings and Brakes. You can get home safely without the AC or fridge working or clogged black tank or broken couch springs.

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