I'm completely lost and need guidance - Center of Gravity for Ram 3500 and Truck Camper

[jcfreese]

Hi folks. Thanks in advance for your guidance. I've been wanting to buy a slide-in truck camper for a long time but to do so, have needed to upgrade my Ram 1500 to a Ram 3500. I recently took advantage of the end-of-year incentives and bought a sweet Ram 3500 Laramie SRW Megacab. I am now in the process of buying a Cirrus 820 shorted camper to place in the back of it. I have plans to then take the truck and the camper to a suspension shop to make the setup a bit more robust. However, as I've dug into this project over the last week, I've seen some articles about Center of Gravity and how this is important. And this is where it gets really murky for me because what is online is not that clear..I understand the basic concepts but can't find really solid numbers nor guidance despite spending a few hours searching the internet.

According to the Cirrus 820 website, the center of gravity is 37" (https://nucamprv.com/cirrus-820/). I found one passing reference that the center of gravity for a Ram 3500 Megacab is 38" but I've also seen a number of charts that have it in other places. I've also seen charts that calculate it from the rear cargo area where I think Cirrus measures from the back of the cab. So again, I'm confused. And then I've seen some truck campers have pictures of huge truck campers on megacabs and say that they ride really well. And then of course, as either the truck and/or the camper gets loaded the center of gravity can shift a bit. All said, I'm confused here. I could, in theory, get out of my megacab truck purchase and instead buy a crew cab but I really love the Megacab setup.

So, in summary, is there anyone with any experience on this topic? Would a Cirrus 820 truck camper safely fit in a 2024 Ram 3500 6.7 Megacab truck bed? Thanks again...you'd be doing me a huge favor by sharing any and all insight.

 

[CdnHO]

Hi folks. Thanks in advance for your guidance. I've been wanting to buy a slide-in truck camper for a long time but to do so, have needed to upgrade my Ram 1500 to a Ram 3500. I recently took advantage of the end-of-year incentives and bought a sweet Ram 3500 Laramie SRW Megacab. I am now in the process of buying a Cirrus 820 shorted camper to place in the back of it. I have plans to then take the truck and the camper to a suspension shop to make the setup a bit more robust. However, as I've dug into this project over the last week, I've seen some articles about Center of Gravity and how this is important. And this is where it gets really murky for me because what is online is not that clear..I understand the basic concepts but can't find really solid numbers nor guidance despite spending a few hours searching the internet.

According to the Cirrus 820 website, the center of gravity is 37" (https://nucamprv.com/cirrus-820/). I found one passing reference that the center of gravity for a Ram 3500 Megacab is 38" but I've also seen a number of charts that have it in other places. I've also seen charts that calculate it from the rear cargo area where I think Cirrus measures from the back of the cab. So again, I'm confused. And then I've seen some truck campers have pictures of huge truck campers on megacabs and say that they ride really well. And then of course, as either the truck and/or the camper gets loaded the center of gravity can shift a bit. All said, I'm confused here. I could, in theory, get out of my megacab truck purchase and instead buy a crew cab but I really love the Megacab setup.

So, in summary, is there anyone with any experience on this topic? Would a Cirrus 820 truck camper safely fit in a 2024 Ram 3500 6.7 Megacab truck bed? Thanks again...you'd be doing me a huge favor by sharing any and all insight.

I believe there is some guidance in the owner's manual. A short bed truck is not the best rig for a camper in my opinion.

 

[Blythkd1]

Shouldn't the truck COG figure be a range? Like 35-40" from the front of the bed, or something like that? (I just made those numbers up) HD truck owners manuals used to always include camper loading data, either in the manual or a supplement. I was about to ask if you've looked for yours but you don't have the truck yet, do you? I'd look for a similar truck and check out its camper data.

Looks like the camper you're looking at is designed for less than 8ft bed trucks so you've got that going for you although at 2850# dry, you'll know it's there. As long as it's more than 37" from the front of the truck bed to the rear axle, I'm gonna say, you'll be in good shape. As long as the rear axle, mainly tires, aren't overloaded that's the main thing. Probably a good deal that you went with the 3500. You're just trying to avoid overloading the rear axle while keeping enough weight on the front axle so the truck still handles safely and correctly. Might be nice to have some air bags to keep the headlights pointed where they should be. Is that the modification you were speaking of?

I used to put an 11ft camper on a SRW 3500 but it was a long bed of course. It was probably in worse shape than yours will be and it still handled fine. How much do you foresee loading the rig down with? Water, supplies and gear, etc?

 

[AH64ID]

My 2022 came with a camper information sheet in the glove box.

I can't find a current Ram slide-in camper guide, but the most recent one from 2017 shows this. The 2024's shouldn't be much different.

Both Dimension A and B are measured from the rear of the bed and the camper CG needs to fall in between those numbers.

 

[Blythkd1]

So 11 - 51 inches from the front of the bed for the heavier option. Seems kinda hard to imagine how you wouldn't hit a range like that with a camper that fits in the bed.

Looks like they don't want the COG of the camper more than 51" from the front of the bed. But as the camper gets heavier they don't mind the COG being a bit further forward.

Again, seems like a considerably generous range.

 

[AH64ID]

So 11 - 51 inches from the front of the bed for the heavier option. Seems kinda hard to imagine how you wouldn't hit a range like that with a camper that fits in the bed.

Looks like they don't want the COG of the camper more than 51" from the front of the bed. But as the camper gets heavier they don't mind the COG being a bit further forward.

Again, seems like a considerably generous range.

Pretty generous, but did you see how low of a weight they recommend the camper be?

The heavier the camper the further forward you want the CG.

 

[MEGA HO]

Long beds are better for the campers, much more options are out there for a 8ft bed.
Saying that if you've got a short bed and a camper made for a short bed then you're good.
Don't overthink the COG as many people do and they'd wear out their keyboards trying to explain how COG "HAS TO BE" in front or above the rear axle.
Ideally it's where you want it to be to put some of the camper's weight to the front axle, but it's not such a big deal if COG is slightly behind as long as you don't overload the axle or the rear tires.
Think about what happens to the weight distribution when you hitch up a trailer? It will put more weight on the rear and take off some from the front.
Furthermore the Cummins weights 900lbs more that a v8 option and all that extra weight sits above the front axle.
You didn't mention whether you went with a 6.7 or 6.4 but that is irrelevant and only shows that there is no simple rule the above mentioned crowd likes to follow, too many variables.
When packing your camper the proper weight distribution is important, pack the heaviest things up front or even inside the cab (like heavy tools, etc).
COG will shift as you mentioned, not sure about the Curris model you're getting but often the fresh water tank is up front and grey / black tanks are further back for easier access to drain valves and hose connection. As fresh water runs out and grey / black tanks fill up the COG will shift farther back.
Now for the suspension mods: air bags are a must to level the rig (IMHO, others may suggest things like Summo overloads, etc) and a heavy duty sway bar will keep it more stable on the road, HELLWIG is to go brand for sway control.

 

[Blythkd1]

Pretty generous, but did you see how low of a weight they recommend the camper be?

The heavier the camper the further forward you want the CG.

Yeah it would be nice to see the OP's payload and camper loading info. Gas truck? Probably ok. Diesel truck? Eh, might be marginal, if you're into those things.

What I found odd about those camping loading specs, on the heavier load it specs out to allow the COG to be a little farther fwd. But the COG can be the same distance rearward in either weight scenario. I found that a bit bizarre. The weights are only 60lbs different though, seems almost pointless on a 2900lb load.

 

[Brutal_HO]

You didn't mention whether you went with a 6.7 or 6.4 but that is irrelevant and only shows that there is no simple rule the above mentioned crowd likes to follow, too many variables.

So, in summary, is there anyone with any experience on this topic? Would a Cirrus 820 truck camper safely fit in a 2024 Ram 3500 6.7 Megacab truck bed? Thanks again...you'd be doing me a huge favor by sharing any and all insight.

 

[jcfreese]

Thank you all...this is super helpful and reduces my anxiety. I've sketched out a drawing with the above numbers and it does indicate that the Cirrus COG gravity is in the range provided. 25.6 from the front edge and 15 from the back range. So I'll suppose I'll be thoughtful on where I store my heavier items inside the camper and put them towards the front.

In terms of suspension, I've spoken to a shop in SoCal that specializes in some of these heavy rigs and they have experience running a Carli Pintop setup with a few add-ons to stabilize things. Based on my discussions with them and the trucks they've worked on previously, I get the sense that as long as I don't get ridiculously heavy they will be able to help out. Again, thank you for all the assistance and guidance...appreciate you guys.

 

[AH64ID]

In terms of suspension, I've spoken to a shop in SoCal that specializes in some of these heavy rigs and they have experience running a Carli Pintop setup with a few add-ons to stabilize things. Based on my discussions with them and the trucks they've worked on previously, I get the sense that as long as I don't get ridiculously heavy they will be able to help out. Again, thank you for all the assistance and guidance...appreciate you guys.

I’ll be honest, I’m not sure Carli makes anything I’d want to run with a high CG load.

Stick to a stock front end, add airbags, and an anti-sway bar to the rear. That’s all you need to do for a camper hauler.