Calculating Tow Capacity of an F350...

[JimmyFisher]

Just purchased a new 375 RES-R and own a SRW F-350 King Cab Lariat with the 6.7L diesel engine. I thought I was going to be good to go on towing capacity, but have been reading and seeing that there are some of you who don't feel like the SRW F350 is enough truck to tow the 16,800 lb. trailer. Can someone teach me how to calculate my towing capacity in simple form? I have the following information on my TV and Trailer:

TV:
GVWR: 11,500 lbs.
GCWR: 26,500 lbs.
Maximum Loaded Trailer Weight Rating: According to my truck manual you calculate this by:
GCWR - (Curb Weight + Hitch Weight + Passengers + Fuel + Additional Payload + Accessories) = Max. Loaded Trailer Weight Rating [IS THIS CORRECT???]
Maximum King Pin Weight Rating: I have no idea how to get this? The Pullrite 20K hitch I have is listed at 5,000 lbs. But what is the truck? Isn't it the lesser of the two?
RGAWR: 7,230 lbs. according to my door tag
GVW: I have no idea how to get this?
Rear Gross Axle Weight: I have no idea how to get this?

5th Wheel Trailer:
Gross Vehicle Weight: 16,800
Fifth Wheel Trailer King Pin Weight: 2,900 [I think - Grand Design info from their specs on the website says "Hitch Weight: 2900 lbs."

Please help me assess my situation.

[JimmyFisher]

Also, how do I find my curb weight? Is it GVWR - payload capacity. So 11,500 - 3,363 = 8,137 lbs.?

[JKellerJr]

Its not the tow capacity they are referring to, its the payload/pin weight. Loaded your probably going to run 3600-3800lbs on the pin which I'm sure is already over the payload sticker on the door. And you still need too add in for passengers and cargo in the truck.

[xrated]

Jimmy Don't be concerned with the towing capacity, you will run out of payload capacity long before you reach the truck's towing capacity....when you are towing a fifth wheel type CAMPING trailer. So it looks like you have 3363 lbs of payload capacity on the truck. That is the payload number for your truck when it was built. If you have added anything to it since then, the available payload will be reduced by the amount of weight of the items added. For example, let's say you added a toolbox for the truck bed and the toolbox and everything you have in it weighs 200 lbs. Your available payload is now.....3163 lbs.

So let's look at the trailer you bought. 16,800 lbs for the GVWR. If you load the trailer to the GVWR, or near that weight, your pin weight is going to be in the ~ 3360 lb range...and possibly a little. The hitch weight/pin weight number that you stated from Grand Design is an empty trailer pin weight, which is all they can give you because they do not know how heavy you will load the trailer (lots of stuff or very little stuff). And I as well, have know idea how heavy or lightly you will pack it to go camping...only you know that. What I will say is this. The accepted method of calculating the correct truck size is to use the trailer GVWR number (16,800 lbs) and multiply that number by at least 20%. Sometimes that actual number will be higher than the 20%, but seldom will it be lower on a 5ver camping trailer. Next, you need to add the weight of the 5ver hitch (175-200 lbs), then add ask of the weight of things that are going in the truck and on the truck....passenger(s), toolbox and tools, extra fuel, firewood, grill, etc. I can also tell you that by using that accepted formula for GVWR and 20%, you are at max payload already, and you still have the other stuff I talked about. It's pretty easy to see how a fully loaded trailer plus passengers and other things in the truck could easily reach 4000 lbs, and that would be on a truck that has a 3363 lb payload capacity....maybe less if you've added stuff to the truck after it was built new.

[JKellerJr]

Also, how do I find my curb weight? Is it GVWR - payload capacity. So 11,500 - 3,363 = 8,137 lbs.?

Yes

That 3363 number is what is being referred to as being to little. I beefed up my suspension and tires and moved on but that is not a popular opinion around here.

[Txfivver]

JimmyFisher I have that same trailer and I hate to say it but you may not have enough truck for it. The 6.7 will pull it fine but the payload will get you. It is very easy to load the 375 up quick. My factory weight sheet showed 3100 pin weight empty. The 200 pound difference is probably the front outdoor kitchen I have, you didn't mention if you did. I added the Onan generator and washer/dryer, both up front, and now I scale at 3860 pounds on the pin. Even if yours is 3100-3200 pounds by the time you load up the truck with people and gear your way over the payload rating on your truck. Only you can decide if your comfortable with that. I found the trailer I wanted, the 375RES, and then bought the dually to safely pull and carry it. My truck has a 5260 pound payload rating so I really couldn't reach that if I tried. Pin weights over 3000 pounds sure pull nicer and more stable with 4 wheels on the rear carrying the load. Good luck and I know you'll love the 375, it's pretty amazing.

[JimmyFisher]

Thanks for all of your feedback. Very helpful. Sounds like i need to invest in some airbags at the back axle of my truck for stability.

JF

[JKellerJr]

Thanks for all of your feedback. Very helpful. Sounds like i need to invest in some airbags at the back axle of my truck for stability.

JF

Just to beat everyone to the punch "it wont change the payload limit according to the sticker".

I would check the tires, more than likely that will be the weak point. I would guess that your rear axle rating will be either really close too or exactly the total of the two rear tires combined.

[JimmyFisher]

So my tires are 3750 lbs at 80 psi, so my combined weight limit is 7500 lbs correct?

[315RLTSinPA]

You will be over loaded on the pin weight. And don't forget the added weight of the hitch and passengers. We looked at a 375 just to look and the salesman wanted to know if we would like to buy one. I told him our F350 wasn't big enough. He said they tow them to shows all the time with SRW trucks. Problem is, we don't go camping with an empty trailer.