RTT and Roof Weight Question

[atx353]

Hey y'all. New guy here from MN. Looking at getting a RTT. My question and concern came when I spoke to Tepui about their 'Lightning' hard-shell tent. They said that I would need a bar system that allowed for 195lbs. After further research it seems my vehicle—a 2015 Jeep Grand Cherokee—has a roof weight limit of 70kg's or roughly 155lbs. I was recommended to reach out to 'Rhino Rack' and inquire about their heavy duty bars that can hold 220lb. From what I understand, even if the bars can hold a higher capacity, the weakest link (my roof's capacity) is the strongest part. They also said that if the roof can hold '155lbs' I would have to subtract the weight of the roof bar system ~10lbs from the capacity, leaving me at about 145lbs. The hard-shell RTT's I am interested in are exactly 145lb, and some are 165lb. So, I have a few questions for y'all who are probably much more knowledgeable than I:

1. I've seen quite a few people with RTT's on their vehicles, is it safe to say that most are pushing or exceeding the dynamic weight capacity? Would going over 20-30lb's cause issues?

2. After doing more research, some of the research suggested getting rid of the factory flush mount, and bolting in directly a 'roof rack' from for example, Gobi. Gobi's roof rack shows a 300lb dynamic weight limit. However, since it bolts directly into the roof, wouldn't it have the same '155'lb limit?

3. I am currently planning on running Thule Roof Bars, would running three help? The local Rack shop says that 3 cannot be run on the factory flush mount, is there a certain modification that needs to be made?

The rep at Gobi stated that, the rack actually increases the limit since it's not the actual roof that has a limit, but the factory flush mount. So, clarification/affirmation on this subject would be helpful, since if the rep was right a roof rack would provide a good piece of mind as to not be maxing out the roof's limit.

Thank you!

 

[rickc]

It's good to see you are asking this question. Too many people will state "I did this and never had a problem".

You are starting a maximum passenger and cargo weight of 1000lb for your 2015 Jeep. The tent weighs 195lb but boasts a carrying capacity of an extra 150lbs on it's own rack so the 195lbs recommended by Tepui was only for the tent. The RhinoRack bars are rated for a combined (2 bars) 68kg or 150lb dynamic on pavement but only 99lb off-road. These will not work; I'm not sure where the 220lb number comes from.

Quick answering of your questions:
1: All depends! If you plan to go off-road then the roof rack loading should be dropped by a factor of 0.66. Exceeding the factory spec by 20lb to 30lb is unlikely to cause a big issue if you are only highway driving and you don't exceed the total passenger/cargo load of 1000lb; think about this: 1000 - 195 (tent) - 20 (bars) - 300 (2 average adults) leaves 485lb for kids/dogs/camping gear. A bigger issue is the ability of a heavy RTT to stay put up top as a function of bar design and how the racks are mounted to the roof, leading to the next question.

2: I agree with the Gobi guy; the limiting factor for your Jeep may be the way the factory roof rack channel is mounted to the vehicle; it's just not designed for very heavy RTTs so your thoughts about a Gobi system are valid.

3: The Thule square bar Podium system is already rated for 220lb (dynamic/on pavement) with two bars for your car using your existing tracks but it may be that the Podium system would overload your factory flush mount system, not necessarily by loading down but due to the combination of up/down/front/back/left/right movement experienced on the road. Three bars may not work due to the curvature of your roof (middle one would stick up!). I would quiz Thule/localrack shop more about this; if Thule guarantee a 220lb loading then you may be good to go.

 

[atx353]

Thank you for your response! I appreciate it. I was looking at the Gobi, and ran across the Front Runner. However, after speaking to a guy at 'Ok4wd' he had stated that they had installed one for a customer and it damaged the roof severely. So, I think my best bet will be to go with a very light weight RTT, or to fore-go it. It's becoming clear to me that the Jeep Grand Cherokee isn't the most optimal vehicle for Overlanding or heavier RTT's in general. Unfortunately the really light RTT's ie. carbon fiber ones are super expensive.

Thanks for your insight. It's brought a few new perspectives to my attention, and given affirmation on the others.

 

[rickc]

A friend owns a Renegade Trailhawk, also roof-load rated for 150lbs by Jeep and he has a CVT RTT up top; exactly 150lbs. It works well for him using the factory cross bars and he does go off road but the RTT looks huge on his little Jeep.

Again, the numbers (if shown at all) are always dynamic, pavement values. I've never seen an OEM manual that states what the roof load is off road; probably a very deliberate action to avoid litigation.

I've also seen damaged roofs and roof racks due to bad loading (kayaks). Some people just don't get basic physics.

Good luck

 

[Lemsteraak]

ATX, you are wise to ask these questions about weight on the roof of the vehicle. Doesn't matter what you load up there, kayaks or roof tents, it all affects handling.

The rule of thumb by the sport bar rack manufacturers Thule and Yakima is 165 pounds as their maximum, and this includes the weight of their racks. Some vehicles they advise less, I'd heed their warnings. Yes, this limit is for here in the US, Thule will rate the same bars in Europe for 100 Kg so I suspect their lower US limit is because of our product liability laws. On the other hand, I talked with one of Yakima's product engineers a long time ago when they were based in Arcata CA. For testing, they used to load up 165 pounds and then take the vehicle off road, so bottom line, they may not have tested their products for over their maximum load. Personally, I would load over 145 pounds on the roof as over that I can really feel it in most vehicles.

You don't need to go to extreme materials like carbon fiber to make a roof tent lighter. An example I know is AutoHome, their small Carbon fiber Columbus for example saves only 15 to 20 pounds. Their standard Columbus is quite light. One secret that the roof tent manufacturers don't tell you is that mattresses are heavy. A good light mattress is expensive. The main reason why AutoHome's Columbus is lighter than their Maggiolina is the weight of the mattress. If you have your rooftent on your vehicle full time, take the mattress out and your will have a tent that is 25 - 45 pounds lighter. Rooftents are one place where less is more. Less weight and less drag costs more.

Since you have read this far, the real question is how much can your load in (or on) your vehicle? If you take the gross vehicle weight limit and subtract the tare weight (what the vehicle weights with fluids), you might be surprised how low it is. I had a guy complain how a 95 pound roof tent affected the handling of his Kia Sportage. When I totaled up what he had and told him he loaded well over 1400 pounds in a vehicle that is rated at less than 800 pounds he was a tad confused. He had no idea he had overloaded his little truck.

 

[MuseChaser]

I've got a lot of similar questions, but I'll try to distill them as much as possible.

What I have: 2005 LX470 w/ factory roof rails and two factory crossbars. Manual says not to put more than 143 pounds on "luggage rack." Tepui Ruggedized Autana 3, 175 pounds. Website and phone rep say "Be sure to mount the racks on your vehicle .. 32"-48" apart for our 3-person tents," and that they're designed for four mounting points on two crossbars. The factory bolt on points for loadbars, i.e., the three-bar set from Rhino rated at 330 lbs, are either closer than 32" if adjacent, or farther apart than 48" if I skip one. The two-bar Rhino set is only rated at 175 lbs, and the rep was adamant about finding something that EXCEEDED the 175 lb weight of the tent. The factory crossbars can be placed at an acceptable spread, but aren't rated for that weight. HOW DO I GET THIS @#$#@ TENT ON MY TRUCK SAFELY?!?!

That is all.. and thank you.

 

[80t0ylc]

I've got a lot of similar questions, but I'll try to distill them as much as possible.

What I have: 2005 LX470 w/ factory roof rails and two factory crossbars. Manual says not to put more than 143 pounds on "luggage rack." Tepui Ruggedized Autana 3, 175 pounds. Website and phone rep say "Be sure to mount the racks on your vehicle .. 32"-48" apart for our 3-person tents," and that they're designed for four mounting points on two crossbars. The factory bolt on points for loadbars, i.e., the three-bar set from Rhino rated at 330 lbs, are either closer than 32" if adjacent, or farther apart than 48" if I skip one. The two-bar Rhino set is only rated at 175 lbs, and the rep was adamant about finding something that EXCEEDED the 175 lb weight of the tent. The factory crossbars can be placed at an acceptable spread, but aren't rated for that weight. HOW DO I GET THIS @#$#@ TENT ON MY TRUCK SAFELY?!?!

That is all.. and thank you.

Well for one thing, your tent weight is not 175 lbs, it's 195 lbs according to Tepui specs - I wouldn't put a tent that heavy on any contemporary OEM roof rack, I don't care what it's rated. With the weight of any roof rack substantial enough to support that tent, you're going to be way above 200 lbs on your roof - and that doesn't even include the weight of an awning, which I'm sure you'll want. That is reeeallllly going to affect your handling and not in a positive way. And the weight of your luggage, camping gear and passengers still have to be factored in. So to answer your question - I don't think with out serious modification to your suspension, which will drop the comfort level of your rig, will you "GET THIS @#$#@ TENT ON MY TRUCK SAFELY?!?!"

Quote from Tepui about this tent: "The Autana Ruggedized™ is the toughest roof top tent on the market. It is perfect for 4x4 trailers and tough off-road rigs." You might think about mounting it on a trailer to take the laden weight off your rig. It would free your LX470 up, for mobility, while you're camping, also.

 

[MuseChaser]

Well for one thing, your tent weight is not 175 lbs, it's 195 lbs according to Tepui specs - I wouldn't put a tent that heavy on any contemporary OEM roof rack, I don't care what it's rated. With the weight of any roof rack substantial enough to support that tent, you're going to be way above 200 lbs on your roof - and that doesn't even include the weight of an awning, which I'm sure you'll want. That is reeeallllly going to affect your handling and not in a positive way. And the weight of your luggage, camping gear and passengers still have to be factored in. So to answer your question - I don't think with out serious modification to your suspension, which will drop the comfort level of your rig, will you "GET THIS @#$#@ TENT ON MY TRUCK SAFELY?!?!"

Quote from Tepui about this tent: "The Autana Ruggedized™ is the toughest roof top tent on the market. It is perfect for 4x4 trailers and tough off-road rigs." You might think about mounting it on a trailer to take the laden weight off your rig. It would free your LX470 up, for mobility, while you're camping, also.

Thanks for the reply. 195lbs is the shipping weight; the tent itself, according to the Tepui rep on the phone, is 175 lbs. No interest in a trailer. Not sure I'm interested in an awning; strange that you're sure I am. I've been backpacking and wilderness ground tent camping for 50 years, 95% of the time w/out an awning. Not saying I'm opposed to having one, just not sure of the necessity yet.

More than willing to make suspension upgrades if necessary (Ripped out the air suspension on a '93 Range Rover County LWB and replaced w/ OME/Bilstein kit myself) but will wait until I know it IS necessary. The LX, stock, is rated for 1200 pounds load, my wife and I weigh 300 combined. Even with a full tank of gas, a 90 lb cargp rack (which we're not discussing, we're discussing three load bars that won't weigh near that much), and all our gear ( we don't have heavy aftermarket steel bumpers, winches, etc), we're nowhere NEAR max load, so I suspect the OEM suspension will be fine, at least to get the tent home. The tent lived the first two years of its life on the roof of an unmodified 2015 FJ Cruiser, crossing the country and up to Alaska.

So, to any of of you who HAVE safely mounted a 175lb soft shell tent on a 100 series using load bars.. how did you deal with the spacing of the three bars? My tent measures 48" x 56" closed up.

Thanks again.

 

[s.e.charles]

is there some type of vertical assist equipment (ladder?) to be included in these conditions?

 

[mikeyb1976]

Hey y'all. New guy here from MN. Looking at getting a RTT. My question and concern came when I spoke to Tepui about their 'Lightning' hard-shell tent. They said that I would need a bar system that allowed for 195lbs. After further research it seems my vehicle—a 2015 Jeep Grand Cherokee—has a roof weight limit of 70kg's or roughly 155lbs. I was recommended to reach out to 'Rhino Rack' and inquire about their heavy duty bars that can hold 220lb. From what I understand, even if the bars can hold a higher capacity, the weakest link (my roof's capacity) is the strongest part. They also said that if the roof can hold '155lbs' I would have to subtract the weight of the roof bar system ~10lbs from the capacity, leaving me at about 145lbs. The hard-shell RTT's I am interested in are exactly 145lb, and some are 165lb. So, I have a few questions for y'all who are probably much more knowledgeable than I:

1. I've seen quite a few people with RTT's on their vehicles, is it safe to say that most are pushing or exceeding the dynamic weight capacity? Would going over 20-30lb's cause issues?

2. After doing more research, some of the research suggested getting rid of the factory flush mount, and bolting in directly a 'roof rack' from for example, Gobi. Gobi's roof rack shows a 300lb dynamic weight limit. However, since it bolts directly into the roof, wouldn't it have the same '155'lb limit?

3. I am currently planning on running Thule Roof Bars, would running three help? The local Rack shop says that 3 cannot be run on the factory flush mount, is there a certain modification that needs to be made?

The rep at Gobi stated that, the rack actually increases the limit since it's not the actual roof that has a limit, but the factory flush mount. So, clarification/affirmation on this subject would be helpful, since if the rep was right a roof rack would provide a good piece of mind as to not be maxing out the roof's limit.

Thank you!

The weight limit of your vehicle is the "dynamic" weight. Which is to mean weight limit while driving. I'm sure the manufacturers artificially lower this number because of stupid people putting too much on their roof and then driving the same around corners, etc.

Installing a roof rack that ups the capacity is wrong, as the mfg states the roof capacity is X amount of pounds. Adding a higher-capacity rack is still going over the manufacturer's limit. For your example, the roof "dynamic" capacity is 155lbs. Putting a rack that can hold 220lbs or 300lbs does nothing, as the roof capacity is 155lbs. You can put a rack on there that could hold 750lbs, but that still doesn't change the fact that the manufacturer's roof capacity is 155lbs. It's a driveablity issue.

That said, if you put an aftermarket rack on your vehicle that can hold the weight of the tent, I don't see a problem with it on the vehicle. You'll just have to realize that if you got into an accident, or something went wrong with your vehicle, exceeding manufacturer's warnings/limits would work against you.

What I have: 2005 LX470 w/ factory roof rails and two factory crossbars. Manual says not to put more than 143 pounds on "luggage rack." Tepui Ruggedized Autana 3, 175 pounds. Website and phone rep say "Be sure to mount the racks on your vehicle .. 32"-48" apart for our 3-person tents," and that they're designed for four mounting points on two crossbars. The factory bolt on points for loadbars, i.e., the three-bar set from Rhino rated at 330 lbs, are either closer than 32" if adjacent, or farther apart than 48" if I skip one. The two-bar Rhino set is only rated at 175 lbs, and the rep was adamant about finding something that EXCEEDED the 175 lb weight of the tent. The factory crossbars can be placed at an acceptable spread, but aren't rated for that weight. HOW DO I GET THIS @#$#@ TENT ON MY TRUCK SAFELY?!?!

That is all.. and thank you.

Like, above, find the actual roof load capacity, not just the rack.

If you put a 3-bar system in, it depends on the mounting type. If you use the factory rack, it's probably a failure point. If it's a mount separate from the factory rack, just install it 48" apart and put a 3rd bar in the middle. The middle bar doesn't need to be attached to the tent. It can just be a helper. The outer load bars get mounted to. It'll be completely fine. Unless the roof had a giant bow and the middle load bar sits higher than the outer ones.

 

[MuseChaser]

...
If you put a 3-bar system in, it depends on the mounting type. If you use the factory rack, it's probably a failure point. If it's a mount separate from the factory rack, just install it 48" apart and put a 3rd bar in the middle. The middle bar doesn't need to be attached to the tent. It can just be a helper. The outer load bars get mounted to. It'll be completely fine. Unless the roof had a giant bow and the middle load bar sits higher than the outer ones.

Thanks very much for the helpful reply. The issue is that I'd like to use the factory mounting points; Rhino offers a three-bar set specifically for the 100 series that lays flat across all three bars. However, the factory bolt holes are spaced at, IIRC, 26" and 28" (something like that.. I'm going from memory, so do NOT use those figures to design anything) for the three aft-most locations. They add up to more than 48", so I can't get the tent to sit on all three at once. The more I wrestle with this, the more it looks like I have to lay out some longer green for a full platform rack. Someone tell me I'm wrong?

 

[Lemsteraak]

I think you may be overthinking the problem. If I'm not mistaken, the concern is weight, a platform is weight. Back in the old days roof tents were designed for platforms and by redesigning the mounting system and tent base it was found that a platform wasn't needed, saving over 100 pounds of weight and green. What was developed was the "universal" mount system and I believe the newer tents from China have adopted the system, so you should be good there.

This leaves the question of weight. Again, a long time ago 165 pounds was accepted as the maximum. Add a third bar, still 165 pounds, this is just a maximum weight for liability and testing. We put our tents and mount systems through simulated crash tests, called a sled test. We used a tent that weighed 165 pounds and another at 145 pounds. So, you will want to get these test results back from your builder with what rack system they use. Yes, we did have expedition tents that weighed more than 155 pounds, our North America limit, but to get one you have to tell us what it was for and why you need it. Many times what makes a good expedition tent, makes one not so good for recreational use.

This is important stuff. Our company's technical advisor was rear ended by a car estimated to be doing well over 100 and his Jeep was totaled. He was pretty banged up, the roof tent slid back on the mount two inches and he moved it to his next Jeep. The tent behaved the same way as in the tests.

This may sound harsh, but if your builder can't produce any test data, and is exceeding the tested strength of the rack system, or is exceeding what the vehicle manufacturer is recommending as a maximum, then you are their tester.