Math Question on WDH's

[KU9L]

I am trying to understand the math to see what I may be overlooking or missing. We have owned 2 5W's, 2 TT's, and a truck camper, so I am accustomed to researching to make the weights work out before we start shopping at RV shows.

Assumptions for full-time RV living:

Classic 33FBT:
UVW 8,261
GVW 10,000
Base TW 1,175 (14%)
Approximate weight of our stuff and a full tank of water added: 9511
Real TW 1,400??? (balanced loads)

This appears to be at the limit of most 14K style hitches and does not include accounting for Me/Wife/Dog (400#), Generator (100#), Fuel (90#), spare 20# LP (38.50#), my Tools (150#), misc camping stuff (50#), or rear Fiberglass Cap (150#) of which part of this load in several ways needs to be factored in as TW also, I have not even mentioned the weight of the Stinger yet (Propride, Equalizer, etc).

We are planning on an F-250/350 upgrade from our current F-150, but since I run an eCommerce business online, I have to have a few extra toys with me than a bare minimum "weekend" style of camping.

Have I met my match or is there a way for the data to make sense so I am not overloading the WDH?

Thank you,

Dave

[Bill M.]

I do not understand yet. The tools, generator, camper shell, wife/dog are payload in the truck, are they not? Then they would not count in the tongue weight (TW). Just in the payload and axle weights. I have see F250's with a 34' and over the rear axle limit. So you need to get a truck with a lot of payload. I am seeing maybe 1400 lbs TW and about 1000 lbs load for a total of 2400 lbs in what you wrote. That should be doable. Even more load if it is in the truck. Maybe get the 350 and check the payload and rear axle stickers carefully. I do not know about hitches for that much tongue weight.

[KU9L]

Originally Posted by Bill M.

I do not understand yet. The tools, generator, camper shell, wife/dog are payload in the truck, are they not? Then they would not count in the tongue weight (TW). Just in the payload and axle weights. I have see F250's with a 34' and over the rear axle limit. So you need to get a truck with a lot of payload. I am seeing maybe 1400 lbs TW and about 1000 lbs load for a total of 2400 lbs in what you wrote. That should be doable. Even more load if it is in the truck. Maybe get the 350 and check the payload and rear axle stickers carefully.

According to Sean at Propride, some of the weight in the truck bed needed to be considered as TW if it was located behind the rear axle of the truck. I think I read the CCC of the truck at 3250# for the 4x4 SB version of the diesel srw 1T. I can deal with that, but I got really confused about what in the back of the truck would be apples and what would be oranges when it came time to calculate WDH requirements. I just did not want to assume I was okay when I may be overlooking something.

I learned the hard way there is never anything such as too much truck when towing 5W's, so getting a solid base with the bumper pull setup to me is crucial considering I will have at least a couple hundred pounds of truck cargo behind the rear axle and a TW of the TT at or near the spring bar limit of 1400 pounds already. I have already determined that another cup of coffee has not given me any real clarity.

Dave

[Bobbo]

Originally Posted by KU9L

According to Sean at Propride, some of the weight in the truck bed needed to be considered as TW if it was located behind the rear axle of the truck.

I don't think this is correct. The tongue weight limit is set by the HITCH. The weight in the bed of the truck, while behind the rear wheels is not ON the hitch.

[slowmover]

Originally Posted by KU9L

I am trying to understand the math to see what I may be overlooking or missing. We have owned 2 5W's, 2 TT's, and a truck camper, so I am accustomed to researching to make the weights work out before we start shopping at RV shows.

Assumptions for full-time RV living:

Classic 33FBT:
UVW 8,261
GVW 10,000
Base TW 1,175 (14%)
Approximate weight of our stuff and a full tank of water added: 9511
Real TW 1,400??? (balanced loads)

This appears to be at the limit of most 14K style hitches and does not include accounting for Me/Wife/Dog (400#), Generator (100#), Fuel (90#), spare 20# LP (38.50#), my Tools (150#), misc camping stuff (50#), or rear Fiberglass Cap (150#) of which part of this load in several ways needs to be factored in as TW also, I have not even mentioned the weight of the Stinger yet (Propride, Equalizer, etc).

We are planning on an F-250/350 upgrade from our current F-150, but since I run an eCommerce business online, I have to have a few extra toys with me than a bare minimum "weekend" style of camping.

Have I met my match or is there a way for the data to make sense so I am not overloading the WDH?

Thank you,

Dave

Armchair “work” isn’t work. Not on a subject prone to misunderstanding (to be generous).

Guesstimates aren’t the thing. Check tire pressure from cold; overnight. Download the Cat Scale App. Head over to nearest and get TARE weight after maxing out fuel carried where the truck carries only driver plus gear kept permanently aboard. This is the adjusted “empty weight” (as opposed to shipping weight).

Adjust tire pressure to lowest point recommended by vehicle manufacturer precedence over Load & Pressure Table; come closest to recommendation. Record all on scale ticket.

Post pics of all PLUS door sticker of axle limits.

Second trip, load the vehicle as though for camping. All pax aboard. New tire reading. Adjust tires per new info. Record all on scale ticket.

The stuff you assume you’ll carry in TT, toss in truck for final of the this stage for a separate weighing. That plus calculated water and full propane is added to TT ship weight.

As to TW, take .78 of the guesstimated number and assume a 40/60 split on FF/RR axles. 440 to Steer Axle and 650 to Drive Axle of a 1.4k TW is close enough. (Only the 650 counts against Payload).

The range of load against axle ratings is the thing when using a WDH. There’s a measured minimum established. Same for tires, which won’t ever be lower than in above (but this is subject to testing, first).

IOW, have working numbers!

Payload and cargo aren’t critical categories. It’s a mistake to try and prop them up as such. Once past TT design, road-going stability is a function of TV design which is steering, handling and braking. Which is specifics of suspension and steering design. Compromise those, and one compromises what was important.

These TTs were designed to be towed by the family car. Nothing new on that. For best all around performance it’s solo duty that dominates vehicle choice.

Experience = hitch rigging quality

Inexperience = buy bigger tow vehicle.

To go from an IFS half ton with rack & pinion steering on a 130” wheelbase to a live axle 170” one ton with steering completely dead is going from barely desirable to thoroughly undesirable.

Same here with “max” in a question about the hitch receiver and hitch specifics. Best performance isn’t necessarily about a “rating” it’s about weight transference. Will it or won’t it achieve FALR? Will that matter?

On a VPP hitch it won’t affect integrated sway control. The TT won’t move out of alignment with 0 or 100% applied. What still matters is braking and handling.

On the first, anti-lock TT disc brakes compensates for heavier pickup problems.

But nothing will fix steering that won’t call for decreased performance with an inferior hitch design (which is all other types).

The likelihood of a TT at GVWR is low, as is a 14% TW. As is a TT above .85 to .92. Try to find some scale ticket comparables where TW is isolated against actual loaded weight.

Get a handle on real numbers. The rest is hot air otherwise. The primrose path. Won’t achieve what you want.

.

[joshjack]

Originally Posted by KU9L

According to Sean at Propride, some of the weight in the truck bed needed to be considered as TW if it was located behind the rear axle of the truck.

That’s ridiculous. It goes the other way, you count tongue weight when adding up payload; but you don’t deduct payload from tongue weight.

The tongue weight is a limitation of the hitch, while total payload is the limitation of the vehicle.

[RandyNH]

Not necessarily, if looking at it as the letter of the law or at the micro detail level, Sean would be correct. It doesn't matter whether the weight is up against the tailgate or on the ball, anything behind the axle will cause said axle to act as the fulcrum, the difference is the further back the greater affect.
When you consider how WD actually works, if just on the ball is dead weight, but where it's main purpose is to lift the middle and apply pressure to the ends (front and rear axles) then any weight in the area of the middle would need to be "lifted" too.
With all that, the amount would usually be fairly negligible, unless you only ride with generator right up against the tailgate only even then it's still closer to the axle and will have less if an affect.

[Bill M.]

I would never question Sean's statements or judgements about trailers.

To me, tongue weight (TW) is a property of the trailer and is determined independently of the truck. But how the hitch distributes that load to the truck varies and I am sure that weight behind the axle is somehow different than weight in front of the axle. So I guess the only thing I did not understand is the use of the term TW instead of some term for actual loading. So when you adjust the hitch to restore weight to the front axle you certainly have to deal with the load in the truck also.

I do not even know my TW. I do know that when hitched the trailer adds 800 lbs to the truck weight and that I restore most of the weight back to the front axle.

By the reference to 1400 wt hitch I assume the OP means the WD bar rating. And yes, it makes sense to me that the loading in the truck affects that.

[Sean Woodruff]

Tongue weight and hitch weight are used interchangeably by some. I don't believe that is correct.

Tongue weight comes from the trailer as the load on the hitch ball.

Hitch weight, the weight to be distributed by the weight distribution hitch, is tongue weight PLUS the weight of any hitch equipment and anything loaded BEHIND the rear axle of the tow vehicle.

I don't use tongue weight and hitch weight to mean the same thing.



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[dznf0g]

Originally Posted by Sean Woodruff

Tongue weight and hitch weight are used interchangeably by some. I don't believe that is correct.

Tongue weight comes from the trailer as the load on the hitch ball.

Hitch weight, the weight to be distributed by the weight distribution hitch, is tongue weight PLUS the weight of any hitch equipment and anything loaded BEHIND the rear axle of the tow vehicle.

I don't use tongue weight and hitch weight to mean the same thing.



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Me neither, however I use term, "receiver weight". This is not tongue weight, as many use the term incorrectly.

[Bobbo]

Originally Posted by Sean Woodruff

Tongue weight and hitch weight are used interchangeably by some. I don't believe that is correct.

Tongue weight comes from the trailer as the load on the hitch ball.

Hitch weight, the weight to be distributed by the weight distribution hitch, is tongue weight PLUS the weight of any hitch equipment and anything loaded BEHIND the rear axle of the tow vehicle.

I don't use tongue weight and hitch weight to mean the same thing.



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With all due respect, I disagree, somewhat. I think we should also differentiate between the "hitch" and the "receiver."

These are the terms I think we need to use to be clear in our conversation:

Tongue weight - weight the trailer tongue supplies

Receiver weight - weight the receiver is rated to carry and includes tongue weight AND WD hitch equipment. This is the number that the hitch label specifies and is often called the hitch weight.

Rear Axle Load - total weight that a WD hitch must try to redistribute to all of the axles.

I agree that tongue weight and receiver weight are different. Tongue weight is the weight the trailer tongue provides. Receiver weight is all weight that the receiver has to support, to include tongue weight and the weight of any WD setup that is in the receiver. The receiver weight is the weight that is trying to make the receiver fall off of the truck.

The weight that is redistributed by the WD hitch is separate from both. It includes the receiver weight (including the tongue weight as one component) and the weight in the bed of the truck behind the rear wheels. That is rear axle load. Receiver weight should not be considered the same as rear axle load any more than tongue weight should be considered the same as receiver weight.

If you have a hypothetical truck with a 24,000# payload and a receiver rated for 12,000#, and put 12,000# in the bed of the truck right beside the tailgate, you have not used up the receiver's rating. You can still put the full 12,000# load on the receiver and be within both the truck's payload rating and the receiver's rating.

I think the misconception is that instead of de-rating the load for the receiver, you should up rate the WD hitch needed for the higher load.

[DreamStreamr]

I like how simply Curt, the receiver company states it. Curt Mfg says, "(TW) The downward force that is exerted on the hitch ball by the coupler. The tongue weight will vary depending on where the load is positioned in relationship to the trailer axle(s)."

[Countryboy59]

Get an f350 with 4000 lb payload and go from there.

[RandyNH]

/\

That was my thought, but I didn't want to start THAT discussion....

[Countryboy59]

Originally Posted by RandyNH

/\

That was my thought, but I didn't want to start THAT discussion....

Well, 1400 lb on the ball will lighten the front axle of a 350 by like 300 lbs. plenty of weight left for steering. Why buy something where you have to even do the math?

My 350 hasn't shaken the trailer apart yet.

[Mollysdad]

Obsessing over payload and tongue weight is offset by a weight distributing hitch. The WD hitch takes some of that "Load" on the hitch and moves it to the front axle, and some to the trailer axles.
If you're towing just "on the ball", then yes, a load in the bed is a big factor. No one wants to over load a vehicle, but until you get weighed, and not just numbers of GVW, it's not correct.

[KU9L]

Ok fellows, I deeply appreciate all of the comments, advice, and wisdom, also because, after 30 years in aerospace I never once threw hardware together just to see if it worked okay. ;-)

We are going for the Classic 33FBT route in getting back to full-timing (been doing emergency eldercare for the past 3 years while we torture ourselves running a campground 100 hours per week). That will be ending next summer as our coach shopping is eventually completed. Looking forward to the Tampa RV Supershow to poke and prod the aluminum in person.

I am specifying the PP 3P-1400 for both WD and anti-sway features for our proposed new F-350 SB w/cap. We traded in our 2012 F-350 dually with 43K miles because it was impossible to park at the bank or any local store I needed parts.

However, Sheila wants a Jeep again. When we camp host in the NSF, we do a lot of AU prospecting (for fun) & the jeep goes places the F-350 only dreams about. We towed a jeep behind our truck camper for many years, so we know what it is like to full-time in a Bambi-sized box with 250w solar and an L.P. generator.

Is it possible to be the only AS owner who brings a jeep with them camping? This alternate proposed TV a friend has may solve my axle/hitch/TW weight issue, plus have an onboard 8KW generator, haul the jeep lengthwise (delete the 5W hitch in the photo during build), carries 100 gals of H2O or separate waste bladders as needed, all of my tools, contains onboard 12v Dometic fridge for the weekly long hauls of perishables back to the CG, ladders, metal detector storage & AU prospecting gear. The truck is titled as a MH in many states (not SD, unfortunately). And it gets around 12 mpg and Sheila drives the 12 spd automatic with ease (our friends' TV like this one). Hmmm, Sheila says we are rebels among rebels. But I still want that PP 3P-1400 hitch for the anti-sway features for the AS. TV (I would get the shorter 10'10" high version) has a way of shading the AS from insects while in route also. ;-)

[slowmover]

May as well get a New Horizons or similar. And spec a mid roof tractor, not a condo.

Too much “stuff”. We all have the tendency.

So how much vehicle weight to support two persons? It’s starting to get ridiculous. And expensive in time and needed tech expertise.

A Grand Cherokee or Durango can tow most all AS. Call up Andy Thomson at Can AM RV. He’s expert in this, when it’s all open-ended.