Traversing difficult terrain with a roof top tent

[MattJ]

Thanks everyone for contributing to my bump on this thread. Rooftop tents are even more popular now than when this post started five years ago. I really appreciate all the input on each specific topic and question I put to the group.

I wanted to also mention that I recently upgraded my rear sway bar to a Hellwig. Maybe it's all in my head (or at least some of it), but it really gives me much more peace of mind when driving with the tent on the roof. The difference is really noticable on highway off-ramps at 40mph - anyone who drives a lifted Jeep with a rooftop tent knows what I am talking about! I tried to take a side-by-side photo of the OEM rear sway bar next to the Hellwig:

I was also thinking I should do some research and add up all of the "bottom weight" that I have added to my Jeep to help with my peace of mind. I know the rock sliders are 120 pounds and my skid plates are 180 pounds. So that's 100 pounds more than the tent weighs, before adding in the armored diff covers and AEV front/rear bumpers. In the cargo area, my fridge and the slide it sits on are darn heavy, too.

 

[Box Rocket]

While a roof top tent is definitely something to consider in difficult terrain and it's effect on vehicle dynamics, it may not have as much of a negative effect as you might think. The way you drive and the lines you choose will have more of an effect than the tent itself.

In this video you can see when compared to the earlier videos of the FJ Cruisers on Poughkeepsie and Blackbear, that slow, smooth driving, proper line choice and avoiding sudden shifts in vehicle weight will make a big difference. (fun fact) the guy spotting the tan FJ on Poughkeepsie is the same guy driving in this video.

 

[DaveInDenver]

Who's the guy in the safety flip flops?

 

[80t0ylc]

While a roof top tent is definitely something to consider in difficult terrain and it's effect on vehicle dynamics, it may not have as much of a negative effect as you might think. The way you drive and the lines you choose will have more of an effect than the tent itself....In this video you can see when compared to the earlier videos of the FJ Cruisers on Poughkeepsie and Blackbear, that slow, smooth driving, proper line choice and avoiding sudden shifts in vehicle weight will make a big difference. (fun fact) the guy spotting the tan FJ on Poughkeepsie is the same guy driving in this video.

While I agree with you on some of this, there is no denying the 100 + pounds above the roof is a serious consideration when attempting off camber routes off road. And NO reason to take it lightly! To say " it may not have as much of a negative effect as you might think" is a prescription for disaster. Not all trails and off roading are on "slick rock". So your comment "that slow, smooth driving, proper line choice and avoiding sudden shifts in vehicle weight will make a big difference." is much easier to accomplish on a solid rock face than when you're dealing with "living room recliner" size boulders, errosion channels, climbing over logs and such. And one more comment, if I may - you don't see many buggy type rigs with RTTs. So common sense would conclude, if you're running a RTT, stay away from buggy type manuvers no matter how bullet proof you think your setup is.

 

[Box Rocket]

While I agree with you on some of this, there is no denying the 100 + pounds above the roof is a serious consideration when attempting off camber routes off road. And NO reason to take it lightly! To say " it may not have as much of a negative effect as you might think" is a prescription for disaster. Not all trails and off roading are on "slick rock". So your comment "that slow, smooth driving, proper line choice and avoiding sudden shifts in vehicle weight will make a big difference." is much easier to accomplish on a solid rock face than when you're dealing with "living room recliner" size boulders, errosion channels, climbing over logs and such. And one more comment, if I may - you don't see many buggy type rigs with RTTs. So common sense would conclude, if you're running a RTT, stay away from buggy type manuvers no matter how bullet proof you think your setup is.

I did say, “something to DEFINITELY consider and the the negative effects on vehicle dynamics”. If anyone reads my earlier post and sees it as a green light to throw caution to the wind as well as common sense, then maybe they deserve whatever damage they encounter on the trail. You know, Darwinism and all that?
I still stand by my earlier comments. Slow, steady driving and good line choice while avoiding sudden shifts in vehicle weight will make a big difference. If someone’s personal driving style, abilities or the trail itself don’t allow for that then common sense would say yeah, a roof top tent might not be the best choice on that particular trail.
On the same page with you 100% on common sense as a necessary part of the equation. I figured most reading here would have enough of that to understand my earlier post without that being spelled out to them.

 

[MattJ]

Thanks again to everyone for keeping this discussion going. I'll continue to post as I build experience and share what I learn. I did some technical trail driving this weekend in Vermont. The first couple days I rode along with some other drivers and on the third day I drove my own Jeep fully loaded with my Tepui Autana Sky tent. I haven't done a weigh-in, but with the condensation mat and other stuff I store in the tent, I'm guessing there's 225 pounds on my roof. I used two 2,000lb cargo straps in addition to the four channel bolts that attach the tent to my roof rack, which is bolted to my roll cage through the hard top. I don't have many good trail pictures, but a few are below. Here's what I learned:

1) I realized that any time I'm on an extended trip with my tent, I have a bunch of other heavy cargo and recovery gear loaded in the back of the Jeep and on the floor of the second row. That helps lower the center of gravity, even though it does put stress on the vehicle and hurts mpg, of course.

2) Go slow. No, slower than that. Really slow. If you struggle on an obstacle, try it again even slower. More momentum or bumping is the last choice with a roof-loaded rig. In an off-camber situation, I was thinking I'd even consider winching before I'd try a bump or momentum maneuver to get over an extreme obstacle.

3) Driver skill and a good spotter are by far the most important factors. I know it sounds obvious, but I told people around the campfire that I learned off-roading is like iceskating: you can tell real quick who's done it twice and who's done it 1,000 times. Some of the drivers in my group ran the whole weekend fully loaded with cargo, kids and roof-top tents, making it look easy.

4) Question for the group, when the vehicle is fully-loaded and heavy, including a roof-top load, would you air down more or less to get to the same handling characteristics? Suppose I like the way my tires handle at 12psi on rocky, muddy trails when it is empty of cargo and has no top. Would I air down to 10psi or 15psi to get the same handling performance when loaded heavy? Lots of debate and theories around our campfire on this topic.

 

[NatersXJ6]

Air down less. Have you ever seen a super light, stripped down Jeep like a CJ or YJ sitting on 36-38” tires at 8-10 PSI and thought they should air down because you can’t see the tire deform?

The goal of airing down is to increase the traction patch of the tire. More weight “squishes” an equivalent tire more. Ultimately, it is probably a moot point, because the difference isn’t measurable, and every driver will be absolutely certain that they know the secret sauce for getting it perfect!

Ultimately though pressure means load capacity. However, even adding 1000 lbs probably doesn’t mean a lot more pressure. Tire manufacturers have load/pressure charts you can use as a guide, and then adjust accordingly.

 

[MattJ]

You mean end up at a higher psi? Stop at 15psi instead of 12psi when fully-loaded and heavy? The added weight on the tires increases the psi by itself, right? I'm trying to figure out how that factors in, if at all. Maybe psi is just psi and the weight load doesn't matter. If you like 12psi empty, then go to 12psi with 500 pounds of cargo too.

 

[DaveInDenver]

You mean end up at a higher psi? Stop at 15psi instead of 12psi when fully-loaded and heavy? The added weight on the tires increases the psi by itself, right? I'm trying to figure out how that factors in, if at all. Maybe psi is just psi and the weight load doesn't matter. If you like 12psi empty, then go to 12psi with 500 pounds of cargo too.

Correct, air down less or run higher pressure, whichever makes sense to you. If the tires and wheels remain the same then the same pressure will result in a larger deformation with more load. You want to air down enough but not so much you risk breaking a bead or unduly stressing the sidewalls. It's the air inside that's supporting the weight. I'll do as much as 10 psi different from a very light day run to a heavily loaded trip. I usually start high (25 or so psi heavy) and burp air if I need, it's easier that way. OTOH I just let my deflators run to their set point of 20 psi as a starting point for a light weight trip and sometimes end up close to 15~18 psi. But I run load range E 235/85R16 on a Tacoma, so I'm not seriously pushing the limits with them. I run them fully inflated at 35 psi.

 

[MattJ]

Thanks. That's what I figured, and that's what we did. Certainly easier to let air out on the trail than add it!

 

[SoDakSooner]

We've run some pretty tippy stuff with the RTT. That said, I prefer without when possible. Pick a good line and be careful and know your limits and in most cases you'll be ok.

 

[Teamoatmealpie]