Weight estimation - DIY Ram 3500 with Total Composites or Box Manufaktur

[MilesBFree]

hi, thinking of building a flatbed camper on a Ram 3500 with single cab and 8' bed. That Ram's payload is 4,600 lbs for the single rear tire axle version and GCW of 11,000 lbs.

I put together a spreadsheet to estimate the weight and while i can get the weight right at the payload ON PAPER, i suspect in the real world weight will be more, perhaps significantly more so. But if I didn't fill the fresh water tank until i got to the last mile before the campsite, it might work.

Wanted to ask if anyone who has built one of these what your finished weight was, if your weight estimation was pretty close, and if it looks like I covered most all of the components. (I know if will vary significantly.) I'm not gonna force this onto a chassis that won't handle it so ok with the answer that i should give up on the 3500 single axle and go to the duellie or even to a 4500 or 5500.

I don't want to go to the duellie version of the 3500 as that adds expense not just for the truck itself, but for the conversion to super singles, lift required for the larger tires, etc. A couple of places show prices around $20k for the conversion. I could very likely DIY that as well and save on the labor cost, but trying to not complicate this or stretch the build time out. Other drawbacks include the weight of the tires when changing a flat, cost for new ones, difficulty balancing, body mods for huge tires, etc. It just snowballs...

And the 4500 or 5500 alternative loses a number of nice cab features / comfort items.

(However, the payload of the duellie version of the 3500 has a payload of around 7,200 - 7,500 lbs so lots of fun to be had outfitting it.)

Looking at this habitat box since i can fit in all mods cons we are looking for:

Wolverine Flatbed with Departure Angle Camper Shell - Total Composites

Wolverine Flatbed with Departure Angle Camper Shell The Wolverine is a premium 4-season empty truck camper shell designed and engineered by Total Composites. This empty shell comes in 2 sizes and it's specifically designed for full-size truck flatbeds. Our proprietary system of extrusions and...

totalcomposites.com

Here is the layout I am thinking (not to scale but this was drawn on graph paper first so design-wise it fits):







Here is the spreadsheet I started:

 

[Victorian]

Thank you for considering a TC camper.
The finished weight can certainly vary by a huge margin all depending on the components and materials you are adding throughout the outfitting. EVERYTHING ads up!! Your 40 gallons of water for example could be down sized to 20. We are 3 people and carry 30 gallons. For us that's enough for 4-5 days. Most times we can spread it even further by using lake water to do dishes etc. Instead of carrying huge amounts of water with you, I would rather bring a decent portable filter system with you like the Stream from Guzzle. guzzle-h2o-expedition-bundle
On average our customers are ending up around 2000lb with a fully outfitted 8' Wolverine FB.

Hope this helps!

 

[mog]

I don't know if it is in your calculations, but if you are installing a flatbed, figure around 400-500 pounds removed for the factory 8' bed.


And if you are going to 37s, did you add in the weight increase for the 4 tires and rims?

 

[MilesBFree]

Thanks Victorian and mog!

Great point on the water. My thought was 40 gallons would go a long way even in the desert, at 2 gallons per person per day (2 - 3 people) plus a couple of showers (2 x 3 x 5 = 30 with no showers). But i tend to plan for all cases; may be better to do a typical case and 20 gallons would do for most. And we could add a couple of jerry cans for the odd occasion where there isn't a lake or stream around.

I like the aquamira drops and those can be used in large quantities. iirc the instructions discuss sterilizing a 55 gallon drum of water. (and filtering - belt and suspenders.)

I will update the spreadsheet to deduct the original bed, mog.

 

[MilesBFree]

Another thought is ditching the generator - the 3500 can be optioned with dual 380A alternators (and the diesel i think are over 400 each?). It's kinda stupid levels of overkill to charge the habitat batteries with a 6.4 liter generator but easy to set up. I am not 100% sure how fast you can charge LiFePo batteries but however fast that is those twin alternators should do it. Guessing that's not how it works... One of the things on my list to research.

But if we were on the move going down the highway i would be charging from the truck engine.

Might run out of battery if we went somewhere and parked for a week and ran the AC every night, though.

 

[Victorian]

Thanks Victorian and mog!

Great point on the water. My thought was 40 gallons would go a long way even in the desert, at 2 gallons per person per day (2 - 3 people) plus a couple of showers (2 x 3 x 5 = 30 with no showers). But i tend to plan for all cases; may be better to do a typical case and 20 gallons would do for most. And we could add a couple of jerry cans for the odd occasion where there isn't a lake or stream around.

I like the aquamira drops and those can be used in large quantities. iirc the instructions discuss sterilizing a 55 gallon drum of water. (and filtering - belt and suspenders.)

I will update the spreadsheet to deduct the original bed, mog.

LOL the " shower" comes up all the time when we talk customers through the purchase. I personally would not plan for an actual shower in a small camper like that. The divider walls for the enclosure take a lot of the "open" space feel away. Instead, I would try to work with a curtain system and something that gets you clean without spashing water everywhere. We have been using the Geyser system and it works fantastic! Almost no splashes and less than a gallon of water to get clean. I can usually do this without a curtain standing in a plastic "shoe storage mat" from Home Depot.

It's much much easier on your truck (especialy when off roading) by going as lightweight as possible. I would rather bring more food and drinks than dead weight.

 

[simple]

Thank you for considering a TC camper.
The finished weight can certainly vary by a huge margin all depending on the components and materials you are adding throughout the outfitting. EVERYTHING ads up!! Your 40 gallons of water for example could be down sized to 20. We are 3 people and carry 30 gallons. For us that's enough for 4-5 days. Most times we can spread it even further by using lake water to do dishes etc. Instead of carrying huge amounts of water with you, I would rather bring a decent portable filter system with you like the Stream from Guzzle. guzzle-h2o-expedition-bundle
On average our customers are ending up around 2000lb with a fully outfitted 8' Wolverine FB.

Hope this helps!

Good info.

MilesBFree, can you post a spreadsheet without recreational gear and personal items to make an apples to apples weight comparison between your design and the average 2000lb build that Victorian is reporting?

 

[MilesBFree]

Sure, here you go!

I suspect my numbers are still low, given we want all mod cons, so will keep working on it. But so far it is in line.

I will upload the entire spreadsheet once it is in a bit better shape, in case it is of use to anyone.

Total figures:

Weight of load			4163​
Safety margin	1​	416.3​	416.3​
Load weight plus safety margin			4579.3​
Gross weight			10979.3​

 

[MilesBFree]

LOL the " shower" comes up all the time when we talk customers through the purchase. I personally would not plan for an actual shower in a small camper like that. The divider walls for the enclosure take a lot of the "open" space feel away. Instead, I would try to work with a curtain system and something that gets you clean without spashing water everywhere. We have been using the Geyser system and it works fantastic! Almost no splashes and less than a gallon of water to get clean. I can usually do this without a curtain standing in a plastic "shoe storage mat" from Home Depot.

It's much much easier on your truck (especialy when off roading) by going as lightweight as possible. I would rather bring more food and drinks than dead weight.

I considered the fact that the shower is a) quite large, and b) would visually take away space in addition to actually taking up space.

but whereas a decent shower for some people is a WAF, for us it is a H&WAF. And the size is due to the H (me) having extra broad shoulders - I was measured for a tux for a wedding and i am 22" wide (thankfully not as deep). Not to say shallow I got in the shower in a Sprinter van conversion and literally almost did not fit inside the shower. my wife had a lot of fun shoving me in and closing the door. I only went in if i faced the side of the van, and being 6' 2" tall my head sort of stuck oput above the shower door top given the slope of the Sprinter walls. to get the other side i would have had to open the door, step out, and have my wife shove me in again. Not making this up. Long story short, 32" is about the least i would be willing to put up with.

I did think of doing just the shower curtain on 2 sides with the right side of the habitat wall (covered) and the side facing the bed being panels (like a little privacy on the bed). But with the toilet in the shower area we would be drawing the curtain somewhat frequently and (ahem) after morning coffee not wanting to hear the, um, dropping a deuce sounds plus odors.

Also, you're not staring at a shower pan and toilet with the curtain pulled back.

Plus the 3rd wall by the entry door would have coat hooks, maybe fire extinguisher, light switches, etc, on it.

So it might be wash (ha!) to looking at the larger structure vs all of that. My reasoning anyway.

Also, 32: is enough to change clothes in, even for me, so if we had a family member or friend stay with us, we could change in there in a pinch.

The Geyser system looks really interesting! Will look at it

But thanks for the thoughts - much appreciate all input and ideas!

 

[MilesBFree]

Numbers are fun so I'll take a stab...

Is the truck curb wt base trim (max payload) or with the options you'd order/buy with ?

Box delete: don't know for Ram but Ford was 366# for box,tailgate,rear bumper, std tire, rim, wheel carrier. before going AL (2017MY) that number was 545#

Might want to check habitat panels being a wash vs windows, entry door, ventilation fan. In an ideal world that would be easy info to acquire.

Wt allowance for a rack for spare tire, rack for kayaks

Is recovery equipment covered by winch, hi lift, tools ?

Thanks for the bed weight numbers!

Yeah, i got a little lazy on the window calc. The Tern windows I checked were pretty light, e.g., 13 lbs for a smaller one such as in the bed overhang. Figured I would cut out at least several pounds of composite panel wall for each, so the net difference was going to be just a few lbs difference.

But thinking about it again now, you might also add a bit more weight for adhesive.

If I add 5 - 6 windows, that could add up. Will need to check the weight for the panels per sq ft.

Good catch on the recovery gear - will add that. I had the HiLift in the spreadsheet, but other stuff like a heavy static strap for an 11k lb vehicle, blocks, etc. will add weight.

I am thinking inflatable kayaks - we aren't hardcore so will be more of a paddle around a calm lake type of thing.

Thanks for the thoughts and questions!

 

[MilesBFree]

The tray is another area i haven't fully figured out.

Norweld makes a cover for the spare tire, which is the angled silver panel just aft of the headache rack in the photo below. I was thinking out the spare there on one side, and the water tank there (in a box made from the same composite panels for insulation), to concentrate the weight in the middle of the truck.

They make a 9' tray that seems to be meant to allow an 8' habitat box plus the spare. But the literature also says not to shift the box backward on the tray to put the spare where the photos show it, so i am confused.

I like the idea of the spare there for a cleaner, more streamlined look overall, but i suppose having it bolted to the rear of the vehicle is a more traditional overland look. I am not overly fussed about that though. Also, not putting that stuff in front of the habitat would allow a passthrough, which is on the list of nice-to-haves but again not overly fussed about it.

In any event, The spare tire carrier and cover if I wen witht something like the Norweld, will add a decent amount of weight.

 

[mog]

Figured I would cut out at least several pounds of composite panel wall for each, so the net difference was going to be just a few lbs difference. Will need to check the weight for the panels per sq ft.

Total Composite side walls (50mm) are 1.9 pounds per square foot. The rear wall could be heavier, depending on if added structure is built in during manufacturing for hanging stuff off the rear of the habitat. The floor (84mm) is 9.08 per square foot.

 

[simple]

There was another thread with good breakdowns on basic weights. I think Idasho had some insightful things to say. I'll see If I can dig it up unless he posts first.

I want to do the same thing you are proposing. Big light box on a single rear 3500.
Super single conversions add a ton of cost and complexity and the average repair shops wont work on anything larger than a 1 ton considering them commercial vehicles.

 

[Alloy]

My experience is not to trust the online data for truck weight. Go to a dealer and check out the payload shown on the door sticker.

 

[Alloy]

There was another thread with good breakdowns on basic weights. I think Idasho had some insightful things to say. I'll see If I can dig it up unless he posts first.

I want to do the same thing you are proposing. Big light box on a single rear 3500.
Super single conversions add a ton of cost and complexity and the average repair shops wont work on anything larger than a 1 ton considering them commercial vehicles.

You don't need to run duals or super singles. The GVWR of my F450 is 14,000lbs. With 2 of the back wheels taken off the capacity of the 4 remaining wheel and tires is 15,880lbs