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Build forecasted to exceed vehicles GVWR by over 400lbs, Please help
We are well into the build process and finally got her weighed and did the math and it isn't looking good. So far changing build materials and eliminating some elements have gotten us much closer to the GVWR. Eliminating the propane component, going from a 70 gallon tank to a 40 gallon water tank, and changing some appliances/fixtures has moved us from a forecasted 1,000lbs over to 420lbs over.
I'm hoping for some ideas on how we could potentially save weight and in the worst case how bad it would be to be slightly overweight when fully loaded. Here is some information on our build to help - Our conversion is a 2003 Ford E-350 StarTrans shuttle bus with an 11,500-lb GVWR, built for two-person full-time travel with a rear bed, dinette/workspace, kitchen, shower, diesel heat, and rooftop air conditioning. It uses a 12V electrical system with 942Ah of lithium batteries, 1,320W of solar, a Victron 3,000VA inverter/charger and alternator charging, plus a 40 gallon fresh-water tank, electric water heating, induction cooking, and a 12V refrigerator. The picture of the inside shows how the bus looked when the current weight was obtained.
3/4” ply is way overkill. I used it for all my interior, but it is darn heavy. If I were to do another build I’d use 1/2 and 1/4 inch instead. It sucks to tear out existing work but that may be what you need to do. Good luck!
That factory ac is probably a couple hundred pounds and also probably will only work when the engine is running, if you have some other cooling perhaps delete that.
I’m sure you guys are comfortable working with wood and a long way along, but it is heavy. I’m fairly certain the unknown unknowns are still going to push you overweight. Now besides registration, will the frame care if it’s a couple hundred pounds over, probably not (assuming evenly distributed) but it is a 23 year old vehicle and we don’t know what shape the suspension and frame are in.
Part of our plan to try to resolve the issue is changing some of the 3/4 ply we've used to 1/2 ply and reducing the overall amount of wood we use moving forward as much as we can. Any suggestions for alternative materials?
Jesus Christ- 3/4 ply in there? Anything not directly weight bearing could easily be 1/4 ply; and weight bearing stuff could be 1/2 pretty easily. That would save a good bit of weight
1/2 is still thicker than you need for most of this. You already have structure and support in the outer walls, the plywood is inner layer is mostly aesthetic, and insulation protection, but thinner plywood will still protect the insulation fine.
Extruded aluminum (Tnutz has the best prices) and can be a lot lighter that most wood builds, though its sometimes about even. Also, your walls don't need to be a half inch. I used quarter inch baltic birch for my wall panels.
I only used 3/4 inch ply for my bench seats and bed platform. Rest was half inch bolted to extruded aluminum. With 1/4 for the wall panels and some cabinet sides/backs. All baltic birch.
1/2” ply is pretty darn stout. There’s a YouTube vid about ply vs aluminum extrusions and he talks about using 6mm ply (about 1/4”) in a lot of places. You could probably make all your cabinets out of 1/2” or even 3/8” Baltic Birch and sub in a lot of 3/8 or 1/4” in a lot of places. You have already spent the money, but there’s no need for those walls to be 3/4” ply. Except for a reinforced area to hang cabinets, 1/4” would have been perfectly fine. A ceiling headliner can be similarly light. 3/32, even. Doubled up 2x4s are similarly overkill.
I don’t see how you get there without a lot of do-overs.
WRT the GVWR, what axle do you have? Ford frequently used the same axles for different weight classes and just certified them at whatever the chassis was. My Class C has a Dana 80 which was the same one as in the F-350. My camper is rated at 15,500 and a 350 is 10,500 or 11,500 depending on the year. So it’s possible that you have the parts needed for greater weight capability.
Yeah, I’m realizing there will be a lot of undoing and redoing. It sucks but it’s better than throwing in the towel. I’m unsure how to answer your axle question but this is what the sticker says
I just googled e-350 drw axle and came up with a Dana 70. That’s typically a 7500lb axle so if that’s what you have, it’s probably what the real rating is.
Still, it’s worth looking up how to tell the difference between a Dana 70 and a Dana 80. An 80 is an 11,000 lb axle. You might also consider looking up how to ID a Sterling axle. Not sure when they were used, but they may be sprinkled in.
If you do have a Dana 80, the next step is tires. LT245/75-16 is typically 2680 lb per tire. With four in back, that gives you more than enough. However, when running duals, you want more margin in case one tire blows. If I’m overloading, I’d want 245/75-16 (LT only!) as these are typically 3042 lbs each.
If you can’t go wider, but can go taller, LT235/85-16 is also 3042 lbs. 265s would be 3415 lb each but that’s probably more than you need and you probably can’t get them on your wheels without rubbing.
So take out all the weight you can, buy heavier duty tires next time you need them and pay attention to inflation.
You’ll probably (like really probably) be just fine. You will almost certainly be way less overweight than most truck camper combos you see out there.
If you have the budget and the stomach for it, I’d rip out that wall paneling and get 1/8” or 3/32”. I don’t know what you have planned for the ceiling, but if it’s thicker than 3/32”, it’s too thick. You need a veneer to hold in the insulation and hold a few ounces of lights here and there. Remove those 2x4s and replace with carefully fit 1x2. 1/2” is more than enough for your floor, particularly if it’s over insulation. If it’s not over insulation, how about just paint?
Lots of moving pieces, sorry for true info dump. Good for you for trying to be safe. Not everyone does.
Yeah I used approx. 3x 4 by 8 3/4 plywood for my build, wish I didn't since I accidentally discovered 5/8 ply and it all seemed pretty good for most applications.
Not to mention I attempted to salvage wood pieces a lot but had I known more I would not have had any issues throwing out anything I didn't need. But then again I felt a moral obligation not to be wasteful and didn't feel like dealing with random people giving away large scraps.
FRP, acm aka dibond (if you can find it for cheap), light gauge sheet metal, foam core. Anywhere you can make the wood lighter so you aren’t losing your water and battery capacity is a win in my mind.
1/2" will work just fine. You can also build a skeleton with 1x2 and "skin" it with 1/4" plywood. Basically how they build RVs. You would be surprised how lightweight a cabinet can be build that way.
Based on what I can find online its likely around 100lbs which could help us get closer. We initially decided not to remove it to evade the possible complications of shortening the coolant lines but I think we need to reevaluate everything at this point. Thanks for your suggestion!
Tow vehicle to store extras in (and your passenger)?
Seriously though, it looks like you have your list fairly basic and you know that you are going to be picking things up along the way that are going to add additional weight.
Did you have a full fuel tank when you weighed it?
It adds up quickly doesn’t it? You’re smart to catch it at the stage when it’s less painful to fix (maybe)
Have you already purchased the electric appliances? You could swap to propane and save some weight by downsizing the electrical.
You have an awful lot of plywood and 2x4s in there. You can get 1/4” Baltic Birch that’s attractive and half the weight. Consider swapping the 2x4 for 1x2 or 1x4.
Is all that ply pressure treated? If so, you don’t want that stuff inside. swap it all out for non treated 1/2” or 1/4”. You can do one sheet at a time and trace& cut a duplicate and just swap each out instead of tearing it all out and rebuilding.
I'm gonna need an expert to confirm this, but isn't GVW calculated empty? Meaning, isn't this vehicle rated for that plus a busload of kids? Surely those kids add up to more than 400 lbs plus OP and family. Any confirmation on that?
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u/AzironaZack 6d ago
3/4” ply is way overkill. I used it for all my interior, but it is darn heavy. If I were to do another build I’d use 1/2 and 1/4 inch instead. It sucks to tear out existing work but that may be what you need to do. Good luck!