Payload Tolerances: how close to max is too much?

[mog]

Regarding the F-550/5500 class trucks...

I'm realizing a big part of my challenge in finding trucks has been that my design called for a very specific truck:

1. Crew Cab (family of 4).
2. 4WD (no off-roading planned, but I live in snow country and want to use it as a snowboard home base and maybe even take it on a beach if possible).
3. Extra-long wheelbase, because I wanted to maximize the habitat size.

Of these three criteria, item 1 + 3 seems to be the hard-to-find combo.

I can find plenty of crew cabs, and a good amount of standard cab long wheelbase F-550's. Finding them together has been damn near impossible unless I'm ok with a rig with 150k+ miles on it.

If I can make the shorter wheelbase work (and clearly I can since I'm looking at F-350's), then it gets a lot more viable.

Here you go. All the benefits of a cabover and longnose combined. Extral long wheelbase. Already has super-singles (the single headache with Kodiaks) Low mileage and killer price with all the existing upgrades (super singles, Kelderman Air Ride suspension, FASS lift pump, most of the factory options, etc.

2007.5 GMC C5500 4x4 CREWCAB - build prepped

- 2007.5 GMC C5500 4x4
- 243" WB / 121" CA (well suited to a 16-18' floor habitat)
- 153,000km (95,000miles)

 

[simple]

For the build your talking about with an RV's worth of stuff, it seems a dually is the best option since your not off-roading.

When I build mine, it will be way more stripped down so I can stay single rear wheel. I like the idea of a shell with camping gear in it. Same idea as my spacekap but with a little more sleeping room and bath/closet for privacy as my child gets older.

 

[ReluctantTraveler]

Perhaps you could give a synopsis of your build plans so it is not necessary to read 15 years of @IdaSHO posts.
It looks like from your materials list you are planning an (unknown size) habitat with 1/4" plywood sheets on the outside, framed with (unknown size) wood 'studs' with (unknown thickness) foam and 1/8" plywood sheets on the inside. No FRP sheeting, inside or out, correct?

Oh yea, good call! Sorry, I've talked about it so much over in the DIY section that I didn't want to bore people by giving a detailed explainer again, but happy to explain!

• 8' box + 2' departure for 10' combined living area
• 5-6' cabover sleeping area
• Basically the 8' version of this: https://totalcomposites.com/flatbedtruckcamperwithdepartureangle/
• 2" studs set every 24"
• 1/4" marine ply exterior, 1/8" marine ply interior
• 1.5" thick XPS foam board insulation interior
• Glue the whole thing together with something like SikaFlex, with brad nails to hold stuff in place while it sets up
• No FRP, but I was going to seal all of the wood before sealing it up, and glass the exterior (and maybe the interior too, maybe)

 

[ReluctantTraveler]

I don’t know the details of your planned construction, but your habitat weight seems very low, especially with all that marine ply. I have a TC flatbed camper, opted for some reinforcement in the rear wall, and I came in well over your shell weight.
40 gallons is a huge amount of gray water.
Flatbed weight seems quite low, but have no idea what you envision. No under-bed boxes? No headache rack?
Need to attach the camper to bed, what will you use? Torklift Fastguns + brackets bolted to flatbed will probably be 50 lbs
Quite a few other weights are pretty obviously low: 3 empty water tanks can’t possibly be 6 pounds, Lagun mount can’t be 1 pound, the Tern door definitely more than 15 lbs, 4 Tern hatches can’t be 2 lbs, you’ll need a MaxxFan for ventilation or something similar
You haven’t accounted for plumbing and wire and power distribution.
Account for fuel and tanks for heat system.
only 5 lbs for tools? and no recovery gear?

this is a start

Also, it could just be that our sensors are awful, but we fill our 26 gallon gray tank in our current travel trailer really quickly, and I'd prefer to not have to hunt for dump stations all the time.

 

[simple]

Also, it could just be that our sensors are awful, but we fill our 26 gallon gray tank in our current travel trailer really quickly, and I'd prefer to not have to hunt for dump stations all the time.

Do you have low flow aerators on all your faucets?

 

[ReluctantTraveler]

So you are laminating the foam panels w marine ply I guess? That will need some not insubstantial coating (more than just paint) to be weather resistant, so that’s more weight. What about the framing and corners? Going to reinforce those w alum angle or something? More weight.

I don’t go “off-road” either, but often on FS and BLM roads and manage to get stuck fairly regularly (4x last year) usually in mud. If you’re often without a truck partner, think hard about a winch. Also a jack, hilift or similar. And even if you don’t expand your tool chest, at least get a patch kit and learn correct use. Has saved my bacon many times.

People have different opinions about SRW vs DRW, but DRW can substantially limit the roads you can go on. That goes for the width and height of your camper too.

Oh and even if you dont raise the truck, at least consider larger wheels, like 35s if they fit without modding, for better clearance and flotation. Oh, and you should get an air compressor if you want to go in sand, or adjust pressure for washboard. And to inflate a fixed flat.

The weight of all this stuff adds up quick.

All really good points. The width in particular is why I was hoping I could make a 1-ton SRW work. Even if you super-single an F-550, they're just wider.

I did plan to glass the rig, didn't think about the added weight there. Thanks!

Which led me to this conclusion about an hour ago...

But point noted: this list is almost certainly under-estimating the weight. Which means the F-350/3500 SRW is almost certainly NOT up-to-the-task even at max available payload.

 

[ReluctantTraveler]

Do you have low flow aerators on all your faucets?

Not on the faucets, but on the shower. With four people, it adds up fast (even taking navy showers).

 

[ReluctantTraveler]

Here you go. All the benefits of a cabover and longnose combined. Extral long wheelbase. Already has super-singles (the single headache with Kodiaks) Low mileage and killer price with all the existing upgrades (super singles, Kelderman Air Ride suspension, FASS lift pump, most of the factory options, etc.

2007.5 GMC C5500 4x4 CREWCAB - build prepped

- 2007.5 GMC C5500 4x4
- 243" WB / 121" CA (well suited to a 16-18' floor habitat)
- 153,000km (95,000miles)

Saw that last week. Sadly over budget for me, or I'd snatch it up in a heartbeat.

 

[simple]

Not on the faucets, but on the shower. With four people, it adds up fast (even taking navy showers).

Good on the sinks too. They are cheap and worth an experiment. Stop your drain and run your sink for 20 seconds. Swap the aerator and see how much difference it makes in volume.

 

[calameda]

I did plan to glass the rig, didn't think about the added weight there. Thanks!

If you’re glassing the plywood and weight is a primary consideration, then why not dispense w the ply and use a FG skin? Will certainly be lighter and just generally better quality, unless you’re particularly good w layups. or you just enjoy many many hours of sanding.

 

[ReluctantTraveler]

Scott and one of his guests discussed this very thing on an EP podcast. They said no more than 80 percent of GVWR.

OHH who is Scott, and do you have a link to this? I'm assuming he's an important Expedition Portal person that I should already be aware of 😂😂😂

 

[ReluctantTraveler]

If you’re glassing the plywood and weight is a primary consideration, then why not dispense w the ply and use a FG skin? Will certainly be lighter and just generally better quality, unless you’re particularly good w layups. or you just enjoy many many hours of sanding.

Ease of working with the material, primarily. And cost.

 

[IdaSHO]

Perhaps you could give a synopsis of your build plans so it is not necessary to read 15 years of @IdaSHO posts.
It looks like from your materials list you are planning an (unknown size) habitat with 1/4" plywood sheets on the outside, framed with (unknown size) wood 'studs' with (unknown thickness) foam and 1/8" plywood sheets on the inside. No FRP sheeting, inside or out, correct?

See if this works....

For what its worth...

Ours is a 7'x14' unit, essentially a 10' cabover camper. Shell itself weighed right about 700#
Been on the road now for 10 years. And looking and performing better than ever.

Fair warning. This method isnt for everyone. It labor intensive, and if you do not mind your weights,
you will be HEAVY. If I were to do it again, Id loose some of the framing as well as drop to a 4mm okoume.
It works great as is, and is absolutely bomb proof, but I feel I could save a bit of weight and cost otherwise.

I drew the entire thing up in Google Sketchup and constructed using the following:

1.5 x 1.5 12ga square steel tube base
Framed with VG fir 1x2's all joints wet set with PL premium and pocket screws
Skinned with 6mm BS1088 okoume using PL premium and stainless brads
Wall cavities filled with XPS foam, tight fit, glued with PL premium
Interior skinned with 2mm birch ply using pl premium and stainless brads
Exterior joints glassed, entire exterior saturated with CPES, alkyd primer, alkyd industrial enamel top coat (recently color change using Monstaliner)
Interior epoxy painted then finish painted with Marine Topside paint

A few photos below... and feel free to snoop in my Flickr that hosts the photos.

DIY EarthRoamer (sorta)... newbie questions

I was referring to how the back end of a long bus moves when the bus is turned. The long overhang allows a shorter wheelbase for a given length vehicle (which is great for twisting narrow neighborhood streets), but does require the driver to be aware of how the back of the vehicle moves. For...

expeditionportal.com

And

yes, 700# for shell only. Complete dry weight as it sits is about 2200#
Wet and loaded, its a bit more than 3000#

---

There are very few penetrations in the exterior (by design)

The exterior grab handle is the only item that is fastened to framing, as it needs a ton of strength to prevent pull-out.
The rear eye-bolts and the front under cabo-over eyes are bolted thru the body, with stainless hardware and rubber washers for seals.
The rest, the solar panel mounts, the roof hatch, lights, etc are all simply fastened to the 6mm ply skin. All are gasketed, some have a bit of silicone.

Truck is a 2011 superduty. Its a heavy-spec F250 (10kGVWR) We still run overweight, (near 12k fully loaded with gear, two adults and two dogs) but it does great.
Extended cab, long bed. I stretched the frame 24" to allow for the 24" x full width cross body box, while maintaining an 8' bed.
I also built the bed, complete with said cross body box, 3-point torsion free subframe, integrated stairs, under bed stowage, etc, etc...

DIY EarthRoamer (sorta)... newbie questions

I was referring to how the back end of a long bus moves when the bus is turned. The long overhang allows a shorter wheelbase for a given length vehicle (which is great for twisting narrow neighborhood streets), but does require the driver to be aware of how the back of the vehicle moves. For...

expeditionportal.com

 

[mog]

Oh yea, good call! Sorry, I've talked about it so much over in the DIY section that I didn't want to bore people by giving a detailed explainer again, but happy to explain!

• 8' box + 2' departure for 10' combined living area
• 5-6' cabover sleeping area
• Basically the 8' version of this: https://totalcomposites.com/flatbedtruckcamperwithdepartureangle/
• 2" studs set every 24"
• 1/4" marine ply exterior, 1/8" marine ply interior
• 1.5" thick XPS foam board insulation interior
• Glue the whole thing together with something like SikaFlex, with brad nails to hold stuff in place while it sets up
• No FRP, but I was going to seal all of the wood before sealing it up, and glass the exterior (and maybe the interior too, maybe)

So a real-world weight if you want to use some calculations to come up with your projected weight.

The professionally built habitat on my Kodiak (flatbed mounted, removable with jacks as I believe you are planning?). 96 inches wide, 96 inches high, 144 inches long (132" at bottom).
The walls are FRP-plywood-foam-plywood-FRP construction, so deduct the weight of the inside and outside FRP, and reduce the weight of the plywood from 5/8" to your planned 1/4" and the 1/2" to your planned 1/8". They were molded as single panels, so perhaps add in your framing. The reason this might be helpful besides the use of plywood, is it is completely finished, windows, door, cabinets, equipment (stove, AC, microwave, sink, water pump, heater, water tank, etc. So with your reductions in weight with lighter construction (this is crazily overbuilt), and add in your cabover section should give you a good guestimation.

FRP-plywood-foam-plywood-FRP construction


Its overall, dry weight with NO water, food, clothes etc is 4040 pounds (weighed on a commercial scale) So IdaSHO's cabin at the low end, and this fat pig at the high end (of course neither the MB1017A or Kodiak care about the weight)
Disclaimer - YMMV

 

[ReluctantTraveler]

So a real-world weight if you want to use some calculations to come up with your projected weight.

The professionally built habitat on my Kodiak (flatbed mounted, removable with jacks as I believe you are planning?). 96 inches wide, 96 inches high, 144 inches long (132" at bottom).
The walls are FRP-plywood-foam-plywood-FRP construction, so deduct the weight of the inside and outside FRP, and reduce the weight of the plywood from 5/8" to your planned 1/4" and the 1/2" to your planned 1/8". They were molded as single panels, so perhaps add in your framing. The reason this might be helpful besides the use of plywood, is it is completely finished, windows, door, cabinets, equipment (stove, AC, microwave, sink, water pump, heater, water tank, etc. So with your reductions in weight with lighter construction (this is crazily overbuilt), and add in your cabover section should give you a good guestimation.

FRP-plywood-foam-plywood-FRP construction
View attachment 817052

Its overall, dry weight with NO water, food, clothes etc is 4040 pounds (weighed on a commercial scale)
Disclaimer - YMMV

Nice! I'd been using Kenny's build (similar size and construction approach) and the weight of a total composites box as comparisons. Yours seems like a bigger build, which makes getting a good comparison from it harder for my smooth brain. But that's cool to see! Thanks!