Open Source Pop up camper design/build

[pods8]

Got my bed yesterday:

[bahndo]

Nice, I'm headed up tomorrow to get mine. Unfortunately work has been killing me the last 2 weeks so if I have any extra time I'm headed for a surf on the way home. The design is coming along, as soon as I have the bed installed I'll start mocking it up to a feel for actual dimensions.

[pods8]

Nice, I'm headed up tomorrow to get mine. Unfortunately work has been killing me the last 2 weeks so if I have any extra time I'm headed for a surf on the way home. The design is coming along, as soon as I have the bed installed I'll start mocking it up to a feel for actual dimensions.

Right on. I've just got the lights (my order is supposed to get here today) and a bracket for the full filler left to do on mine and it's wrapped up. I had to rework my drop sides because they sent 8.5' long ones for my 7.5' bed but that's done now.

[adam88]

Hi Bahndo,

First of all, it sounds like a great project! I am building my own pop-up camper and custom aluminum flatbed and it is a lot of work but rewarding. I will anxiously tune in to see how you are doing.

However, I must bring up (sorry to be a wet blanket) some safety concerns I have. Since you have children I feel obligated to bring these up, and then you can do what you need to do with them. I wouldn't be able to sleep tonight if I didn't mention them.

The concern, as someone else mentioned, is your truck. Normally I wouldn't chime in, but I just feel I need to let you know that the 2007 Dodge 2500 MegaCab Diesel 4x4 simply does not have the payload to handle what you are asking it.

It's unfortunate, but Dodge made these trucks essentially to only transport passengers and fuel and nothing else. The payload from the factory on your truck is 1590lbs. That is almost the same payload as a Toyota Tacoma has, and far less than an F150. So much for the "3/4 ton".

The payload number of 1590lbs does not include passengers or fuel, or any upgrades to the truck (bigger tires, front bumper, etc). The truck has a 35 gallon tank of diesel, which weighs 250# full. If you add 4 passengers (assuming you are all skinny, at a combined 500#), you are left with only 840# of payload.

The reality is, I am building my camper to be as light as possible (aluminum flatbed, composite walls, etc). and I still plan on it being at least 2500# when it is all said and done, with water, fuel, food, and so on. To give you an idea of how little 840# is, that would barely be enough to handle most of the Four Wheel Campers, and those are at dry weight. FWC recommends about 1500# of payload total for their campers to budget for water, extra batteries, food, clothes, etc. It adds up quickly.

Best of luck and sorry to be the bearer of bad news.

Adam

[kjp1969]

The concern, as someone else mentioned, is your truck. Normally I wouldn't chime in, but I just feel I need to let you know that the 2007 Dodge 2500 MegaCab Diesel 4x4 simply does not have the payload to handle what you are asking it.

Where is the weak link: axle, tires, springs or chassis? In other words, is one or more of these systems spec'ed for lower weight in favor of comfort? If so, could a system from a 3500 series truck be substituted? Max payload for the 3500 is listed at 3380 lbs.

[adam88]

Where is the weak link: axle, tires, springs or chassis? In other words, is one or more of these systems spec'ed for lower weight in favor of comfort? If so, could a system from a 3500 series truck be substituted? Max payload for the 3500 is listed at 3380 lbs.

Where is the weak link: axle, tires, springs or chassis? In other words, is one or more of these systems spec'ed for lower weight in favor of comfort? If so, could a system from a 3500 series truck be substituted? Max payload for the 3500 is listed at 3380 lbs.

Good question. Most manufacturers (to save costs) use the exact same platforms for their 2500 (250) and 3500 (350) trucks, except the 2500's have a lower GVWR/payload. This is usually caused by two simple things: Tires/Wheels, and Spring ratings. For instance, my F250 is identical in every single way to the F350 except for springs/tires. However, my F250 came with the camper package which added the the same rear suspension as an F350. So the only difference is tires, and I have since upgraded to 19.5" wheels. Therefore, my truck is essentially an F350 (and I've rebadged it as so and call it an F350).

In regards to the 3380# payload, I believe you are looking at DRW version of the 3500. Here are the payload capacities direct from the 2012 towing guide. Keep in mind, Dodge has made a lot of changes to their trucks over the past 5 years to compete with Ford, so these payload #'s are much higher than previous generations (e.g., 2007) mega cabs:

Mega Cab, Diesel, Short Bed, Laramie, Automatic, 4x4:

2,000# = 2500
2,490# = 3500 (SRW)
3,550# = 3500 (DRW)

Source: http://www.ramtrucks.com/en/towing_g...wing.Specs.pdf

So the 3500 SRW only has a 490# payload over the 2500. This is likely from the springs/tires. Even at 2490# though (which is the 2012 upgraded ram), it is still going to struggle to handle a camper. Because these numbers, as mentioned before, do not include fuel or passengers (or accessories), the reality is that useable payload is only around 1700# with 4 people and a full tank of fuel. FYI, compare these numbers to a Ford below and you will see the differences between Dodge and Ford payload, and why Ford is considered the king when it comes to hauling. I looked into all of this when I decided which truck to buy and it is one of the reasons I went with Ford:

Ford

Ford, Crew Cab, Diesel, Short Box, 4x4:

2,630# = 250
4,000# = 350
5,670# = 350 (DRW)

A 4000# payload on a SRW crew cab diesel truck from Ford is pretty spectacular IMO. Source: https://www.fleet.ford.com/truckbbas...Pickups_SB.pdf

[bahndo]

This is all good information and is important to look at. I picked up the flatbed last week so once I get it installed I'll go weigh the truck and see where I'm at. At this point I am definitely leaning towards going very light weight without lots of extras that aren't going to get used much if at all. We basically want some space for sleeping and changing and hanging out between surf/ski sessions. As a familly we weigh a whooping 300lbs total which I expect to only reach ~450lbs over the next 10 years so at least we get a little weight savings there .

[adam88]

This is all good information and is important to look at. I picked up the flatbed last week so once I get it installed I'll go weigh the truck and see where I'm at. At this point I am definitely leaning towards going very light weight without lots of extras that aren't going to get used much if at all. We basically want some space for sleeping and changing and hanging out between surf/ski sessions. As a familly we weigh a whooping 300lbs total which I expect to only reach ~450lbs over the next 10 years so at least we get a little weight savings there .

hey bahndo. Since I am planning my own camper, here is a rough calculation I did for it. This is for an 8'6" x 7' camper (exact same size as your UTE flatbed), so quite small. It will be a pop-up camper. Maybe this will help.

Fiberglass = 1.03# per square foot @ 1/8" thickness
Honeycomb Panels = 0.15# per square foot @ 1" thickness
Aluminum Corners =3.53# per square foot @ 1/4" thickness

So total wall thickness will be 1.25" and then the aluminum will just be used for the corners (GXV/Unicat style). The camper is going to have a total of 394 square feet of composite for both pop-ups inclued. It will also have a total of around 80 square feet of aluminum. So the totals look like:

1.03# x 394 x 2 = 811.64#
0.15# x 394 x 1 = 59.10#
3.53# x 80 x 1 = 282.40#

So I am looking at well over 1150# for the camper before even considering anything inside. Oh and this doesn't include paint, which, although not too heavy still adds weight. So as you can see, keeping things relatively as light as possible.... I mean, this is about as light as something like this gets. I originally planned 2" walls and those went out the window as soon as I saw weight.

Now if I factor in my desired water supply (100 gallons), and battery supply (510ah), just those things alone would add another 1150#, bringing my total to 2300#. So ultimately, something has to give and I'm not sure what it will be. In my case, it's either weight or convenience. Do I need a 100 gallon tank? Or 510ah? Maybe, maybe not. If I chose to keep all of the above, the fully loaded product would probably approach 3500-4000#.

The one big thing I have going for me is my truck is a regular cab and therefore has a better payload capacity and more ability to even the weight out. I am also going to have an incredibly low centre of gravity because of the pop-up camper, so these are two things I consider from a safety stand point. My truck has a payload of 4300# so I am also very comfortable there. The thing is, I do not want to approach that 4300# though, but I very well may end up doing it. Even then, I will be making a lot of modifications (19.5" tires/wheels and custom leaf springs probably, removing all blocks entirely from the rear, maybe air bags, stabalizers, rear sway, etc).

Whew. So anyways, lots to consider. Hopefully my example helps you to kind of understand what you're up against trying to keep something under weight. Your biggest hurdle is that your wheel base is not friendly to you at all. Because of the mega cab, any camper you build is going to not only put the full load on the rear axle, but also remove weight from the front axle. You ideally want the majority of weight of a camper right in front of the rear axle and that is a challenge with any short box, but especially a challenge with a long wheelbase and short Cab-to-axle mega cab. These campers get very heavy fast. Even Four Wheel Campers absolute basic camper isn't any lighter, it's actually heavier per square foot than my design. They have an overall lighter design due to the usage of the pop-up material. But still, their shell weighs 650# for a full-size model and that's just the shell. The grandby weights 850# and that's with no options... shocking.

As you can tell, I enjoy talking about this stuff...... just realized how much I typed! lol well hope this helps.

[SChandler]

bahndo, sounds like you are on the right track by weighing the truck after the flatbed install to see what you are working with in reality, not the land of "manufacturer's payload estimate". adam88 makes a good point about the weight of the campers and gear and the importance of understanding how much it all weighs prior to construction.

adam88, have you weighed your truck to verify that you have all of the rated 4300lbs of payload on your Ford? The manufactures base their payloads on stripped down models. If you ordered anything but the basic XL model, you're working with less payload than you thought. Not trying to be rude, but it sounded like you are basing all of your calculations on the Ford's published numbers, rather than what the truck actually weighs. For both trucks I've owned, the published weight and payload have been verify different from the actual weight and payload.

[pods8]

You'll probably pick up at least 100lb weight savings with the ute deck only (ie bedsides removed) verse your stock truckbed/tailgate if I had to guess. That's just based on my impressions from man handling the two different beds around to swap them out.