F450 Custom Composite Expedition Truck - ALL THE DETAILS

[Allysonoverland]

After 5 years of vanlife with my dog, I finally decided it was time for a new build.

My travel style has changed a lot over the years. Instead of staying local in the lower 48, I've now driven to Alaska and Mexico, and hope to drive the PanAmerican some day. I'm ready for a rig that can go further, stay longer, and is large enough to adapt as friends fly in to visit or my family grows in the future.

After a ton of research, I’m knee-deep in building a custom expedition truck / composite shell camper.

I’m very much a want-to-know-everything type of person when it comes to any investment I’m making - so I’ve spent endless hours on forums and Facebook groups gathering information that helped me determine the best decisions for this project.

I’m starting this thread to share the knowledge I’ve gathered and hopefully help the next person on this journey save a little time and stress. By no means do I pretend to be an expert on ANY of this - a lot of this stuff comes down to personal preference, budget and your needs. But if you’re interested in a thread that compiles a bunch of answers to questions about these custom composite camper builds, all in one place - you’ve found the right thread.

So - let’s start with the basics. Why go custom? Well, after years on the road and off-grid, I realized that none of the traditional truck campers really fit my wish list - new or used. I've become very particular about things and the systems I want in my "home" on wheels.

I considered modern innovative campers like the NuCamp Cirrus 920 which comes off-grid ready.. But the cost of mass manufactured, pre-built truck campers are steep these days. And by the time I’d customize an older one to suit my wants and style, I might as well just start from scratch.

I love the design process and wanted to create something that actually works for me, rather than making compromises on layouts and doing renovations.

Additionally, I’ve worked in composites (non-truck camper related) for nearly 6 years. So I know a thing or two about the panels typically used in these builds - and find them to be superior to most options on the market. Composite shells, when done right, are lightweight, insanely well insulated, and impervious to water.

So, in the end, a custom build just made the most sense for me. YMMV.

 

[Allysonoverland]

So, let’s talk about the panel options. There are quite a few popping up!

Many shell suppliers I looked into either limited the size of windows allowed, didn’t include basic features like wire channels in the ceiling, or only offered standard sizes that didn’t quite fit my vision. I also asked around, dug into feedback on forums, etc. to reach my final decision.

In an effort to not discredit any company, I’ll just share the links with you of the various custom camper options I researched (as of March 2025). Pricing from my original quote from the various builders I spoke with in 2024 has likely changed. But, at the time, aside from Boxmanufaktur (from EU) - most of them were within the same ballpark of each other - give or take a few grand.

Companies worth looking into (this is not an exhaustive list, just the ones I know of):

Lemker Overland (supplier to):
- Bison Overland
- Labyrinth Overland
- Glampervan USA

Total Composites (supplier to):
- Bear Adventure Vehicles
- OutPost campers by San Juan Vans
- Hunter RMV

Cascadia Composites (supplier to):
- Montana Van Company
- Mesa Overland
- Off-Grid Customs
- Overland Adventure Truck

GlobeTrekker (supplier to):
- Pariah Fabrication
- Foundation Vehicles
- DIY-ers

Boxmanufaktur

Whiskey Tango Campers

Ultimately, I chose to go with panels from Cascadia Composites. Here are some of the reasons for that decision:

• The HD fiberglass skin - literally makes a hammer bounce off of it. I will be much less scared to hit branches on the trail with an exterior this durable.
• Zero wood in any of their shells
• The heavy duty, reinforced floor. Some companies use the same panels on the floor as they do on the roof..didn’t love that.
• Customizable sizing
• Wire channels in the ceilings included in the quote
• Very little structural limitations on the window sizes
• Insulation value - their 3” panels are around r15
• Ability to do a color other than white

I also went out of my way to visit Cascadia co-owner, Quade, in person in Washington, before making the decision. He spent years assembling shells from other panel manufacturers before deciding to make his own to address the shortcomings he was seeing in the market.

After spending half a decade in the van space and knowing way too much about the various components - I truly appreciated being able to talk and brainstorm with someone who knew way too much, too. With Cascadia being newer to the industry than others on this list - meeting Quade definitely gave me more confidence in the decision to try these panels.

Unfortunately, Quade was booked out too far in the future for my timeline - so I ended up working with Off-Grid Customs out of BC, Canada to have the shell assembled.

Off-Grid was able to do a custom “kerf” nose cap - which I love. It gives the camper less of a “assembled kit” look. I’ll attach pictures here.

Off-Grid goes above and beyond in a lot of ways. They put UV-stable beads on every joint when assembling the camper, and do extra surface prep and testing on their methods. I appreciated the little details like this. But what really made me happy was that they hauled ass to get this camper out of Canada before the potential Trump tariffs hit next week. It just shipped TODAY and I’m so stoked.

It will be delivered to my builder, Montana Van Co, very soon, where he will start the interior according to my designs.

In my next posts, I will talk about how/why I chose a truck platform, super single wheels, flatbed suppliers and more.

 

[Allysonoverland]

I ended up choosing the F450 pickup as my chassis for this project. Here's why:

With the load I was looking at hauling (about 4,100 lbs +/-), I was really already narrowed down to 2 trucks in North America - Ford or Ram. I considered the RAM 4500 and 5500 too, but admittedly, past experiences with Stellantis products left a bad taste in my mouth. I was able to find ample pros and cons to both - I suppose if you look hard enough you'll always find something wrong with anything. Ultimately, I decided that I liked the exterior look of the Ford more (personal preference).

Once I knew I was going with Ford, it was time to compare the different models.

First, let's compare the f450 dually to a f350 dually. It is true that the payload of a f350 dually is better than the f450 dually (by a few hundred pounds depending on the specs). However, I knew from the get-go that I didn't want a dually at all. I have seen rocks get stuck between dually wheels off-road, didn't want to deal with 6 tires, and personally I think they're just plain ugly. So, I always planned to convert whatever truck I bought to super singles.

The f350 front axel is more narrow than the rear, which is why it's nearly impossible to find information on super single conversion options for the f350. And, with the wider front axel on the F450, it actually has a tighter turning radius. If I recall, the difference is about 8 ft in turning radius. This makes a huge difference in tight parking lots and on narrow backroads.

With the F350 dually ruled out - it was F550 vs F450. The F550 only comes in a cab & chassis model. The F450 comes as a regular pickup or a cc. The pickup model was much more enjoyable to drive than the bouncy f550 cab chassis. Obviously, adding a load of weight would help this, but there were other considerations too..

The F450 pickup (has a bed) is a bit of an anomaly - it’s not detuned like the F550 or CC F450. And it also seems to be rated to stay just below commercial use specs, while still having bigger brakes. This was important when considering insurance costs.

In my home state of OK, I found that insuring an F450 pickup as a personal vehicle was significantly easier and cheaper than the F550 cc. I know some people who have managed to get personal policies on their F550, but I didn't have such luck. So for me, the F450 made more sense financially, too.

Unfortunately, it's important to note that the F450 pickup (as of 2024) doesn’t come in a super cab - only single cab or crew cab. This was a downer, since I originally wanted a super cab. It’s also only available in diesel, which might be a downside for some, but that wasn’t a dealbreaker for me.

The last thing I'll mention when considering your build platform is this - do you want to always be running your truck at max capacity? In theory, the components of a truck will wear down faster when being fully loaded 24/7. Buying the 450, which is built beyond what it is spec'd for, also gave me some peace of mind knowing I likely wouldnt be pushing my truck to its limits every day, even when I'm loaded at max capacity.

In the end, going with the F450 pickup, I get a more powerful, luxury-filled truck with a tighter turning radius and reasonable insurance costs. It’s a win all around in my book.

 

[YukonMontanaTannerTrapper]

I'm curious why the diesel engine is not an issue for you ? If you plan to take this rig to Central & South America one day, doesn't the high sulfur content in the diesel fuel that you might get there concern you ?

Thanks for posting this. It's interesting and that's coming from a guy that's not really into build threads.

 

[Allysonoverland]

I'm curious why the diesel engine is not an issue for you ? If you plan to take this rig to Central & South America one day, doesn't the high sulfur content in the diesel fuel that you might get there concern you ?

Thanks for posting this. It's interesting and that's coming from a guy that's not really into build threads.

This is a great question. Honestly, starting the Pan-American is still a couple years out for me. However, through talking with other friends who have made part of the journey already and searching forms, I've come to determine the accessibility of ULSD in Central and South America is changing rapidly. It is of course still a concern, but not as much as it used to be. Laws are continually changing and pushing for ULSD (aka Euro-Diesel, Puma Ion, etc).

As of right now, I know there would be places where I'd need to stock up before, or power through quicker (Nicaragua, Honduras) due to their current diesel quality. Perhaps park & rent a car to explore while in those places if it's still an issue. But I am hopeful that by the time I start making the drive things will have changed even more. But even if they haven't, the journey is still doable.

Countries like Costa Rica, while being higher than 15ppm, are still less than 50ppm and this is generally accepted. The few commenters I've heard from indicate their modern systems have handled this without issue, so far.

Another consideration would be finding DEF if the system isn't deleted. It sounds like the DPF regenerates more often in South America than in the US (from a combo of the general roads/terrain or just the quality of diesel, I am unsure?). But I know it is advised to buy a few cases of DEF every time you're in a major city, just in case. This was true even in Baja last time I was there.

At any rate, I found this article to be quite informative on the accessibility of ULSD.

So.. did I consider it? Yes. But I am not worrying too much about it yet. Without a doubt, stocking up on a few extra OEM fuel filters, and installing an extra fine filter and water separator may be in order before the trip south. But I will cross that bridge when I come to it!

 

[rruff]

I like the F450! One difference of the pickup model vs C&C is the fully boxed frame, so you should be able to mount the camper without an articulating subframe. I'd opt for the C&C though if I was building one, for the engine and wheelbase options.

Since your payload won't be that high, will you use LT tires rather than military?

 

[Allysonoverland]

Another good question! Sounds like you’re already well versed in the super single topic but I’m going to use your comment as a starter to write my next thread about this... skip to the end for my answer!

Super Singles on an F450? LT Tires vs Military for super singles???

Quick background info: “super singles" are single tires that are weight rated high enough to replace the capacity of a dually set.

Converting to super singles from a dually has many benefits. I’d recommend checking out this article from Truck Camper Magazine for a run-down on the pros and cons of super singles.

As you’ll quickly learn, military grade tires are often used in super single set ups, because of their high weight capacity.

However, I am a 5’2” woman traveling solo 95% of the time, and the idea of me changing a military grade 41” heavy tire (200ish lbs with the rim) on a backroad alone is honestly laughable. Most men doing this are installing winch systems to help lower their spare. So, there are ways to make it happen, but it’s certainly not ideal imo.

Tires that big also require a lift and would raise the height of the truck even more, so with as small as I am, getting in and out would become more cumbersome too.

So.. I don’t want big tires, but I want single rear wheels and a big camper… so what’s the solution?

While super singles are meant to replace the full capacity of the dual wheels, if you are not using the full payload of your truck - technically you don’t need tires to be rated that high either.

Enter: the rising concept mentioned by @rruff of using standard light truck (LT) tires as super singles in place of the usual large military tires.

So, to be clear, using LT tires is generally for those who do not need the full payload capacity of their truck but want the benefits of a SS conversion. If that’s you, there are quite a few benefits to going with an LT tire. Such as:

-Higher speed ratings
-Improved ride quality
-Cost savings vs the expensive military tires
-Easier accessibility to replacements at standard tire shops
-Little to no body modifications are required (substantial body mods required for 40”+)
-Potential to store the spare in factory location (like 37” or smaller)
-The larger 41” military tires will wear out the front end components quicker

Cons of going with LT:
obviously you will lose some rear axel capacity - it becomes limited to the combined total weight rating of the tire you choose. (Ex: if your tires are rated for 4,000 lbs each - you now can not exceed 8,000 lbs total on the rear axel)

20” seems to be the standard size for super single wheels.

Suppliers of super single wheels:
Wehring Motor Co
Buckstop Truckware
DBL Design
Stazworks
Modified wheels from Alcoa
Custom orders from Wheels Now

(I recommend this Super Singles Facebook group to stay up to date on new options)

**Note: make sure when buying your 20” SS wheel, you buy one that is compatible with the LT bead. An MPT bead is different. You must match your wheel and bead to maintain DOT compliance. Most SS suppliers mentioned above offer both.**
____

Okay, cool, lets talk SS tire alternatives…

These are the best LT r20 options I know of, as of January 2025.

Falken WildPeak R/T (38”)
38x13.50R20
Max load: 3,970 lbs
Suggested rim width: 9.5-12
Total diameter: 37.8 lbs
Tire weight: 70.4lb each

Toyo Open Country R/T (38”)
38x13.50xR20
Max Load: 3,970
Suggested rim width: 9.5-12.0
Total diameter: 37.8
Tire weight: 86 lbs

Toyo Open Country R/T Trail (35”)
LT295/65/R20
Max Load: 4,080
Suggested rim width: 8.5-10.5
Total diameter: 35.1
Tire weight: 64 lbs

Nitto Terra Grapplers AT (35”)
LT295/65/R20
Max load: 4,080 lbs
Suggested rim width: 8.5-10.5
Total diameter: 35.12”
Tire weight: 61.66 lbs

Nitto Ridge Grapplers (35”)
LT295/60/R20
Max load: 4,080
Suggested rim width: 8.5-10.5
Total diameter: 35.2”
Tire weight: 69.40

Nitto Ridge Grapplers (38”)
38x13.50xR20
Max load: 3,940 lbs
Suggested rim width:: 9.5-12
Total diameter: 37.76”
Tire weight: 89.29

Fury Offroad Country Hunter MTII (37”)
37x12.50xR20 LT
Max load: 4,190 lbs
Suggested rim width: 8.5-11
Total diameter: 36.8”
Tire weight: 88 lbs
——

*BONUS - don’t mind the body mods required for a 40” tire but still want to go LT?*

Fury Offroad Country Hunter MTII (40”)
40x13.50R20LT
Max load: 4,300
Rim width ranges: 8.5-11
Total diameter: 39.8”
Tire weight: 89.8

—
*BONUS #2 - some people don’t know that Continental also makes a smaller MPT tire:

Continental MPT 81 (37”)
275/80/R20
Max load: 4,674 lbs
Suggested rim width: 9”
Tire weight: 102 lbs
Max Speed: 68 MPH

I have seen companies like Reiselt's Machine Works run these tires on Wehring wheels. I think it’s a good compromise for size and weight capacity, if you don’t mind the narrow width. They will cut into mud more.
—

Alternatively, if you just don’t want the big tires, but do need the full payload of your truck:

Founders M/T Radial offers a R19.5 beadlock wheel (alum or steel) and a 36” tire with a max load rating of 6,610 lbs each. Read about pros/cons of beadlocks here.

They do offer a 19.5 non-beadlock wheel now too, but I personally would not want to air down a 19.5 without beadlocks...thats a conversation for another day.

——

So after all this research - what’s my plan? The truth is - I don’t know. I have calculated down to minor details an expected weight of my new camper and the modified truck, but nothing will be more accurate than actually weighing in.

So for now, the plan is to load the truck up and weigh the axels, and then decide on a wheel/tire. My camper is going to be removable (with a passthrough!!) so taking it off to do the truck mods later isn't the end of the world.

For the reasons outlined above, I will do my best to avoid anything over 38” - but if a 41” military tire means staying safe on the road, that’s what I will do. It’s all TBD.

If you know of other higher rated LT tire options, or alternative Super Single setups not mentioned, I’m all ears

Hope you all find this helpful!

Pictured: a Buckstop F450 super single conversion from their website, because 😍

 

[dstefan]

Kudos on one of the best researched, written and clearly laid out build plan threads I’ve seen on this site!

 

[Allysonoverland]

Kudos on one of the best researched, written and clearly laid out build plan threads I’ve seen on this site!

Thank you for the kind words, means a lot! 😊

 

[Bob W]

Great thread so far!!

You likely considered this but did not see it mentioned an additional issue to note regarding tires size is how it may effect final drive gearing. Just want to do the math to make sure you will still be in the sweet spot to get the best mileage and drivability.

 

[rruff]

There are a lot of 37" tires you could use that weren't mentioned. The SS wheels tend to be pretty wide also (10"+) so the tire should be wide, ideally 13.5" I think.

Did you get the single cab or crew? If your load CG is in front of the rear axle (and it should be), you should have plenty of capacity with LT tires.

 

[Allysonoverland]

Great thread so far!!

You likely considered this but did not see it mentioned an additional issue to note regarding tires size is how it may effect final drive gearing. Just want to do the math to make sure you will still be in the sweet spot to get the best mileage and drivability.

Excellent point to consider. Again, this is stuff I didn't really know about until I started this project so I would love to share info to help the next person understand what you mean here..

If you'd like to know my conclusion for tire size on the f450 pickup, skip to the end!

Comparing the 6-speed to the 10-speed f450 pickup (4.30 axel ratio)

2017-2019 F450 Pickup (6 speed trans / 6r140)
-Overdrive (OD): 0.674

2020+ F450 Pickup (10-speed trans / 10r140)
-Overdrive (OD): 0.63

Why Tire Size Matters:
Larger tires cover more ground per rotation, which lowers your engine RPM at a given speed. The key is balancing tire size with gear ratios to keep your RPM in the optimal range for fuel efficiency and drivability.

The sweet spot for fuel efficiency in these trucks is usually around 1650 RPM at 65 mph. This is slightly above the engine’s peak torque (1600 RPM).

For best results...
Get a 2020+ F450 pickup if you want to run 37” tires. The 10-speed transmission and lower OD ratio keep RPMs within the sweet spot for efficiency.

Get a 2017-2019 F450 pickup if you want to run 41” tires. The larger tire size compensates for the higher OD ratio, bringing the RPM down closer to optimal cruising speed.

Here's a useful calculator to calculate tire size, gear ratios and rpm.

 

[Allysonoverland]

There are a lot of 37" tires you could use that weren't mentioned. The SS wheels tend to be pretty wide also (10"+) so the tire should be wide, ideally 13.5" I think.

Did you get the single cab or crew? If your load CG is in front of the rear axle (and it should be), you should have plenty of capacity with LT tires.

Crew cab! Yes everything heavy is in front of the rear axel. There is a false floor that allowed me to put my water tanks all the way to the front, as well as the fridge / other heavy components. I have tried to find an answer on what percent of the weight might end up being shared with the front axel when loaded this way but couldn't find an answer. Would love any insight you may have.

 

[Allysonoverland]

Lets talk about "torsion free" subframes.

This one is a can of worms that I have seen debated over and over again and honestly I still do not feel qualified enough to provide a true opinion. But I will dump what I think I know here.

Unimogs, for example, have frames that are designed by Daimler to flex drastically with the terrain. When you’re off roading with a frame that is more flexible, you have to deal with the torsion somehow - otherwise your camper will end up being the stiffest part of the setup and take on all the load (which could damage / crack your habitat). The argument is, that a subframe alleviates those points so that it doesn't transfer to your camper.

However, the general consensus I’ve gathered is that not all trucks need a subframe. The chassis you choose, plus the weight/size of the box and the terrain you like to go to are all important factors to consider when deciding if you need a special subframe for your camper.

In relation to Ford Trucks, the 2017+ F-250 / F-350 / F-450 pickups have a fully boxed frame for stiffness. The frames are built of more than 95 percent high-strength steel with up to 10 crossmembers, and are 24 times stiffer than the older generations. The frame is designed to minimize flexing and twisting while maximizing strength and torsional rigidity. This means in theory, outside of extreme cases, the stiffness of the frame should prevent transfer of the torsion to your box.

In contrast, the 2017+ F-350/F-450/F-550 chassis cabs have a fully boxed frame under the cab and forward, but have c-channel aft of the cab. The more flexible C channel allows the frame to flex more. This concern is what drives the discussion about the need for a torsion-free subframe on cab chassis trucks like the Ford F550.

Some interesting discussion on the differences between the frame rails of ford pickups vs cab chassis can be found here.

There are certainly people on this forum who have direct mounted campers to a flexible chassis without a subframe and reported back without issue. I have no idea what terrain they’re traveling but can only take them at their word. Some argue this topic is over-thought and hyper analyzed. I am not an engineer and encourage you all to draw your own conclusions.

I did find this thread discussing subframes to be interesting (it’s a lot of information, mostly about the Fuso FG).

All this to say - since my build is going on a Ford f450 pickup (stiff frame) and my camper floor is only 10 ft in length - I have opted to not do a special subframe. I will remove my pickup bed and replace it with a custom flatbed. My camper will then be mounted to the flatbed. Semantics of that entire process will be disclosed at a later date.

I made this decision after reflecting on the reality of where I’d actually be taking this camper. I love off-roading, finding a site in the middle of nowhere that most people can’t get to/don't know about, and staying for a week or two. But I do this while keeping in mind that my entire home is on the back. I have zero intentions of rock crawling with this thing. I just want a capable vehicle to be able to go where I wanna go and get myself out when I mess up Everyones use case is different and should be factored into the decision.

If you are looking to source a subframe, I don’t have a ton of resources for you because I decided not to go this route, but here are a few off the top of my head:

Globetrekker
DDG Overland
Overland Adventure Truck
Bowen Customs (with a flatbed)
Off-Grid Customs (with a flatbed, I believe for their camper customers only)
+many more I'm sure.

Next, we will discuss all the different rabbit holes I went down to find a custom flatbed for this camper, and the various suppliers I came across. From the most expensive, to most budget friendly options!

 

[rruff]

I have tried to find an answer on what percent of the weight might end up being shared with the front axel when loaded this way but couldn't find an answer. Would love any insight you may have.

For instance if you have a 160" wheelbase and the CG of your added load is 24" in front of the rear axle, then 136/160 of the load will be added to the rear axle, and 24/160 to the front. If the CG of your load was 24" behind the rear axle, then 184/160 of the load would be added to the rear axle, and 24/160 removed from the front.

At least I think that's right... simple lever arms. With your bed removed you'd surely have less than 3k lbs on the rear axle, so if you keep the CG of a 5k lb load in front of that, you'd be ok.

Will you use the rear seat for storage? How does your camper floor sit relative to the rear wheels?