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

[MilesBFree]

It's going to be overweight, or if not, suffer from poor handling. This is purely speculation, so I am open to being wrong. The TC campers that are now 50mm all around will be lighter than the the ones built with the 83 mm roof and floor, so that could work in your favor going with 50 mm all around but once you add up everything in a 'real world' scenario I can see this thing being heavy, maybe not overweight but enough to make the handling suffer.

I agree on the handling. I have done a lot of suspension work on track cars so this wouldn't be completely new territory and I'm pretty confident i could come up with the right mods for a 3500 to handle the weight at or close to GVWR, but that will add weight too...

But likely won't be under GVWR so am likely going to scrap this idea

 

[andy_b]

We took a few days off to get our kid to college but are back now.

I agree that this isn't likely going to work. I thought of several more non-trivial items to add and it's looking closer to 11,500 - 12k lbs GVW and likely to go higher. So the 3500 platform is likely out for what we want to do.

And in terms of travel goals / journeys, we aren't looking at weekend trips but rather extended overlanding-type things, like out for a couple of months at a time (with short stints at more traditional campgrounds for laundry, resupply, etc. So the weight as used is likely to be higher.

The reasoning behind the 3500 was to get a truck with more comfort and safey options than the 500 offers (in a single cab), stay within some of the National Park road restrictions, 5-ton bridge limits (yeah, I know 11k is over 5 tons , easier maneuverability, 37s instead of super singles (I'm not getting any younger and wrangling 200lb-plus tires isn't terribly appealing), the MPT 81s* have a bad reputation for balancing, roundness, etc.

Just doesn't look do-able in a hard-sided box. Popup, could probabl;y make it work.

Going to step back for a little while and reconsider the 5500 or F550 option. But then it might snowball and add another 2' to the box since the floor plan i came up with was a bit cramped. But at that point you are basically building a more robust and much more capable C-class RV that is also a lot more expensive. The option to buy a used C-class even cheaper and tow our old Land-Rover behind (or trade our other car for a jeep or new Land Cruiser) starts to come back into play. It's not apples to apples but if we change direction i would want to consider all alternatives.

* has anyone used the Goodyear G275 instead of the MPT81? I haven't seen a whole lot of info on it other than some basic specs and that it wears a lot longer.

The 550 is available in Lariat trim and the 5500 is available in Limited - IDK exactly what "comfort and safety" options you're looking for, but it isn't as though these are only available with vinyl floors and milk crates for seats.

There is also no reason why you necessarily need to go to MPTs/G275 on super singles on a 550/5500 as long as your build doesn't eventually creep past the weight ratings. Toyo makes a 40" with a 4190lb weight rating.

The camper plus the gear you described building in your initial post will cost about $70-90k, not including labor. It could easily remain in the 3k-4k wet weight range. When mounted on a 550/5500 chassis, you'd be safely within the weight rating and with none of the issues of the 350/3500. Likewise, you don't have to commit to the truly huge and expensive MPTs or G275s if you can avoid approaching the max weight rating of the 550/5500 chassis. Then, you'd have a camper that is still a convenient size, easier to drive (due to the 550/5500's better turning radius), and much more robust.

 

[MilesBFree]

Thanks for all the inputs, @andy_b, much appreciated.

The 5500 Limited is only available in a crew/double cab and i was hoping to keep it to a single cab since there will only be 2 of us, to keep the length down. Will check the F550 Lariat.

Agreed I wouldn't be sitting on milk crates (but actually did that back in the day in the Scout I learned to drive on for a couple of days until we fixed the seats).

And I am not fussed about things like contrast stitching in leather on the dash. But the SLT (highest 5500 trim available for a single cab) you lose the cooled (fan) seats, some seat adjustability, better stereo, power and heated mirrors with memory, interior storage, etc. Not sure if i would spend the money to upgrade seats and stereo. If scheel-mann offered theirs with cooling fans, it would actually be better for the truck to come from the factory with cheaper seats as i would buy those in a heart beat after sitting in them.

I saw that Toyo last night but it was for a 20" wheel diameter, and the weight didn't seem to be all that much less for the tire and wheel combo.

The ideal combo would be an 18" diameter wheel and a 37" tire. I haven't been able to find a wheel like that in 10-lug pattern though - wondering if the brakes or other components made it necessary to go to a 20" wheel? Will do some more searching.

I agree - 5500 / F550 is looking like the way forward.

Oh, and totally agree on the bathroom being non-negotiable. Get rid of that and I might be considering a pop-up, an E350 4x4 van or something in that general vicinity, or RTT.

 

[andy_b]

Thanks for all the inputs, @andy_b, much appreciated.

The 5500 Limited is only available in a crew/double cab and i was hoping to keep it to a single cab since there will only be 2 of us, to keep the length down. Will check the F550 Lariat.

Agreed I wouldn't be sitting on milk crates (but actually did that back in the day in the Scout I learned to drive on for a couple of days until we fixed the seats).

And I am not fussed about things like contrast stitching in leather on the dash. But the SLT (highest 5500 trim available for a single cab) you lose the cooled (fan) seats, some seat adjustability, better stereo, power and heated mirrors with memory, interior storage, etc. Not sure if i would spend the money to upgrade seats and stereo. If scheel-mann offered theirs with cooling fans, it would actually be better for the truck to come from the factory with cheaper seats as i would buy those in a heart beat after sitting in them.

I saw that Toyo last night but it was for a 20" wheel diameter, and the weight didn't seem to be all that much less for the tire and wheel combo.

The ideal combo would be an 18" diameter wheel and a 37" tire. I haven't been able to find a wheel like that in 10-lug pattern though - wondering if the brakes or other components made it necessary to go to a 20" wheel? Will do some more searching.

I agree - 5500 / F550 is looking like the way forward.

Oh, and totally agree on the bathroom being non-negotiable. Get rid of that and I might be considering a pop-up, an E350 4x4 van or something in that general vicinity, or RTT.

Yeah, sorry if my reply seemed dismissive of your needs in terms of options - I agree with trying to get what you want. FWIW, if you decide to go the custom TC box route, I highly recommend considering a north-south bed configuration. In that scenario, the length of the cabover then becomes the same (approx) as a crew cab truck. Definitely adds to overall length, but not having to crawl over your partner may be worth a three point turn every now and again…

I have some Scheel-Manns: no amount of fans, AC, music or massage could make a factory seat better than them lol. I would add them to any truck we had. They’re so good, even my wife (Director of the Department of Skepticism) thinks they are a must do upgrade in the future.

TBH, I did not realize that the weights between the two were so comparable. However, at least the Toyos are Q rated for speed. I’ve had a set and they are loud, but not as loud MPTs. Also, although they get pricey in that size range, the Toyos are still slightly cheaper than MPTs and/or MSAs.

Getting wheels is tough - my plan was to have a set made by TrailReady. Buckstop also makes some nice wheels (I think they are made for them by TrailReady or vice-versa). The folks at TrailReady can make a wheel in any size, bolt pattern, and bead profile. They could provide a lot of useful info.

It will be expensive, but building a truck of this category is an expensive proposition. Doing it yourself though allows a lot more flexibility and value than buying one off the shelf. I also think it gets you a setup that is much more capable than many other commonly considered options (eg - popups, vans, etc).

 

[MilesBFree]

Oh no worries! It's good to poke lots of holes in this now before i spend any money. All comments and suggestions welcomed.

Could you put the longer overhang for a N-S bed on a single cab? Or is the torque on the panels too much with my rather large, ahem, personal frame hanging out that far from the main box? The box isn't braced to the truck cab or chassis, correct? The photos seem to have these just cantilevered out into space. I have seen some relatively small 90-degree brackets on the overhang but those were on a box with shorter overhang.

Maybe an issue with the air it would catch under the overhang and try to lift the box, if the N-S longer overhang box was installed on a single cab?

 

[MilesBFree]

I sat in the Scheel-Mann seats for a couple of hours and they were awesome. My wife was skeptical too but I had her sit in them at Overland Expo East last year and she is now sold.

Fans would seal the deal

 

[andy_b]

Oh no worries! It's good to poke lots of holes in this now before i spend any money. All comments and suggestions welcomed.

Could you put the longer overhang for a N-S bed on a single cab? Or is the torque on the panels too much with my rather large, ahem, personal frame hanging out that far from the main box? The box isn't braced to the truck cab or chassis, correct? The photos seem to have these just cantilevered out into space. I have seen some relatively small 90-degree brackets on the overhang but those were on a box with shorter overhang.

Maybe an issue with the air it would catch under the overhang and try to lift the box, if the N-S longer overhang box was installed on a single cab?

I am vain and I think that the long overhang would look weird on a single cab. The cab over doesn’t care, however.

The side panels of our box have reinforcements along the rooflines to add additional cantilever support in additional to external supports. TC does a great job of engineering your final product to work based on your design goals. I think if you wanted to have a north-south arrangement, TC could accommodate.

 

[MilesBFree]

Here's the more-or-less final version of the spreadsheet for the Ram 3500 analysis. When I start to build this I will redo it but for now it served its purpose and for what we want the 3500 won't work.

Both the total weight and load weight would probably be AT LEAST 400 - 500 lbs over. Significant compromises would need to be made for what we want. YMMV if you aren't looking for all the bells and whistles but even then I would be willing to bet you would come in at or just under GVWR and payload. And stripping it down some would kind of defeat the purpose of going with a higher-end box.

Please scan this before opening - I have anti-malware on my computer but in this day and age you never know.

http://www.fd3s.net//Truck%20camper%20weight%20calculations.xlsx

 

[andy_b]

…

http://www.fd3s.net//Truck%20camper%20weight%20calculations.xlsx

This all seems like a great build to me.

IMHO, I would delete the generator, the WeBoost (since you’ll have Starlink), and propane. I think solar and LiFePo batteries have come along enough to provide all the power you’d need. Of course, I don’t actually know what your power needs are so the advice is worth what you paid.

We have not spent a tremendously long time off grid yet, but we use a small 2 gallon hot 120V domestic water heater. This is easily recharged by our solar (800w) on a sunny days and has thus far been adequate for our limited use. We have not tested it in the winter so take it with a grain of salt. If you guys are the type to stay put for days-weeks at a time in a ski resort lot or similar, this may be an issue. If think you’ll start the truck on a regular basis, you could also supplement solar capacity in the winter with a DC-DC charger.

 

[MilesBFree]

This all seems like a great build to me.

IMHO, I would delete the generator, the WeBoost (since you’ll have Starlink), and propane. I think solar and LiFePo batteries have come along enough to provide all the power you’d need. Of course, I don’t actually know what your power needs are so the advice is worth what you paid.

We have not spent a tremendously long time off grid yet, but we use a small 2 gallon hot 120V domestic water heater. This is easily recharged by our solar (800w) on a sunny days and has thus far been adequate for our limited use. We have not tested it in the winter so take it with a grain of salt. If you guys are the type to stay put for days-weeks at a time in a ski resort lot or similar, this may be an issue. If think you’ll start the truck on a regular basis, you could also supplement solar capacity in the winter with a DC-DC charger.

Thx. I hadn't yet gotten as far as tiling / puzzle piecing the solar panels on the roof but did at least figure out 4 would fit. It depends on the physical size (obviously) and the wattage and to maximize it might need to install a mix of those, which may drive need for multiples of at least some of the electrical management components (DC-DC converters?) Will figure that out eventually; at this point i am primarily looking at weight and dimensions.

I did some back of the napkin calculations and think 5 - 6 of the 200 watt panels would do the trick EXCEPT for an electrical hot water heater. That may be do-able too but at that point I decided the 3500 wasn't going to work so i left it for a while. i.e., didn't finish googling for combo heater (i.e., furnace-type) and hot water heaters. Maybe tankless? But a 2-gallon type would do the trick for even a long-ish (by camping standards) shower if you figure 2 gallons of hot and 3 - 4 of cold. (Blowing through that much water would be for a spot with water supply...)

If I do go the 5500 route, i might add another 2' to the floor plan which would allow at least one more of the 200W panels, or possibly one of the 275W ones. And if I extended the overhang for N-S bed, maybe one more. If so would very likely not need the generator or propane.

Since on the topic of electrical and appliances, initial thoughts are on a 12VDC fridge and an induction cooktop that can be moved from inside to outdoors. At that point, everything is electrical so def. no need for propane.

 

[MilesBFree]

Arm chair observer here... FWIW couple things on your spreadsheet, no big deal either way.

The weight reduction figure or box delete includes deleting the oem spare. Therefor that oem portion (93#) should be added back to the full size spare line.

10 sheets of ply for cabinetry. No idea but sounds a lot.

interesting, if we remove the water and genny weights the finished camper comes to ~2,964. By comparison Northern Lite lists their 9.6' unit with top trim, loaded, NS bed, A/C,rear bumper platform, etc at 2,950. Not saying your numbers are wrong but it is a bit of a bugger that an 8' diy comes to almost 3K.

As for your conclusion ... it can be a short path from a 11k RCLB with a 8' camper to a 5500 Crew on military SSs and a NS cabover camper (!)

That inbetween market above 4,500-5,000 payload but before the class 4,5 chassis is currently filled by the oft maligned 1 ton dually. Have you completely ruled one out ? Many folks seem to have. Likewise many seem to have decided to just run over with their SRWs and forgo that big truck jump.

My 2c on the 1 ton srw is that 12k itself shouldnt neccesarily be a non starter. Indeed some 350 configs have >12K GVWR. It isn't for us at any rate, but our cog is low. I'm not sure what the other problens with a 350/3500 alluded to earlier are.

Funny and frustrating (for me at least) that as light trucks have gotten more capable with higher rims and tire ratings, payloads, RAWR and GWVRs, , coupled with the promise of lighter composite materials for campers and batteries now available, we still run into this need for "a little bit more" out of a 1 ton srw.

And we watch the increase in super single conversions to class 4/5/+ trucks (again something not easily available before). Of course, some won't want the extra width and weight of wheels and increased weight of chassis.

But here we are.

Good luck with it !

Good catch on those - will update it.

Yep, probably heavy on the cabinets as far as the wood goes, but that was before i figured out you don't need backs on the boxes and they are glued to the habitat walls. But i also didn't include hinges, pulls/locking mechanisms, and hydraulic struts for the overhead ones.

I kinda like the 8020 aluminum extrusion approach, but from what i have read that will be slightly heavier.

Actually, the Northern Lite one is pretty close to what i am considering in terms of features, so a good reference point.

I do need to go back and look at the duallie again, as you said.

Thanks again!

 

[MilesBFree]

this popped up on my feed last night, illustrating the purpose of this thread Actually I shouldn't lol at this since they probably depended on bad advice from the salesperson plus i don't know what the circumstances are. Sorry for being a d***.

In any event. it looks like a 3500 Cummins since it has 8-lug wheels and the badge on the fender. The Cummins reduced the payload since it is heavier; that is max payload of 6280lb including people, gear, etc. Allowable rear axle weight is around 7k lbs. At first glance it seems like it could possibly have worked.

Spec sheet for this brand is below too.

 

[MilesBFree]

Did more searching and found an article on that. Owner said:

"...both the Ram dealer and the camper company where we bought it said it was the perfect truck," Pavel explained. "They said it should handle the load no problem. I knew the payload capacity on the truck was about 7,800 pounds and the camper dry weight was close to 5,000 pounds, but fully loaded, probably about 6,500 pounds."

So yeah he was probably over by 200 - 300 lbs which is likely what Ram is thinking so they won't cover it.

Broken Ram 3500 Dually Shows a Camper Can Still Overload a Big Truck

This Ram 3500 is awaiting a $17,000 repair job after an enormous slide-in camper snapped its frame.

www.thedrive.com

 

[andy_b]

Thx. I hadn't yet gotten as far as tiling / puzzle piecing the solar panels on the roof but did at least figure out 4 would fit. It depends on the physical size (obviously) and the wattage and to maximize it might need to install a mix of those, which may drive need for multiples of at least some of the electrical management components (DC-DC converters?) Will figure that out eventually; at this point i am primarily looking at weight and dimensions.

I did some back of the napkin calculations and think 5 - 6 of the 200 watt panels would do the trick EXCEPT for an electrical hot water heater. That may be do-able too but at that point I decided the 3500 wasn't going to work so i left it for a while. i.e., didn't finish googling for combo heater (i.e., furnace-type) and hot water heaters. Maybe tankless? But a 2-gallon type would do the trick for even a long-ish (by camping standards) shower if you figure 2 gallons of hot and 3 - 4 of cold. (Blowing through that much water would be for a spot with water supply...)

If I do go the 5500 route, i might add another 2' to the floor plan which would allow at least one more of the 200W panels, or possibly one of the 275W ones. And if I extended the overhang for N-S bed, maybe one more. If so would very likely not need the generator or propane.

Since on the topic of electrical and appliances, initial thoughts are on a 12VDC fridge and an induction cooktop that can be moved from inside to outdoors. At that point, everything is electrical so def. no need for propane.

The arrangement of panels, hatches, etc is definitely an exercise in patience. In this regard, the assistance from our builder, Pronghorn Expedition Vehicles in building out the panel arrangement via CAD was invaluable. We are using SunPower flexible panels (100w x8) - rigid home panels are much more productive in terms of watts per square foot but heavier. Being able to run heavier panels is another 550 benefit.

A side note and plug for working with Pronghorn EV - if you choose the custom TC box route, there is no 20% tax on the panels (that is, the tariff on goods into the US from China). In addition, construction of a custom box in the US could involve substantial shipping fees. US Customs considered the completed camper as a Canadian product. The labor (labour) cost was favorable due to the exchange rate. It is not cheaper, but for us, it ended up in a higher value product to go custom built in Canada.

We included a themostatic mixing valve in our system. I'm definitely no plumber, but this should've increased our system's efficiency as it pertains to hot water usage.

An 1800W induction cooktop should be no problem - that is about the same draw as the water heater and will be on continuously for a much shorter time. We also use an electric kettle (~1400w) for coffee, etc with minimal impact. Our fridge is a 95L Dometic - it has no appreciable impact.

 

[MilesBFree]

Checking out the Pronghorn builds now!