RTT w/ Factory rails - Risks?

What are my risks here if I use Thule 450 Crossroad mounts, square bars, and factory rails? Need some help as I'm spinning in circles searching forums. I purchased a Tepui Hybox roof top tent that weights 155 lbs for my '18 Jeep Cherokee KL Trailhawk w/ 2" lift. I was planning to use factory rails with Thule 450 Crossroad mount w/ square crossbars. However, I cannot find any specs for dynamic weight for factory roof rails, yes I checked the manual. Some forums say 150 lbs dynamic and Rack Outfitters shows 165 lbs dynamic. So…I’m either exceeding the dynamic weight by 5 lbs or under by 10 lbs w/o the ladder in the tent.

Also, I am planning to go off-road on trails, like Engineers Pass in Ouray. I plan to purchase RRO roof rails but I don’t have time before a 2 wk camping adventure. As a side note, I'm not exceeding the vehicle cargo capacity and static weight on top will only be ~465 lbs (rack, tent, gear, wife and I). Thanks everyone!
 

rgallant

Adventurer
Good luck, I had the same issue on my Discovery , it is info that is very hard to find for some reason. One site I found for your vehicle says 150 from the 2017 owners manual, that would be dynamic. I would think you would be fine, as you are are only a few lbs over. Static is harder to guess 3 times is normally used, adding a 3rd bar might give you more peace of mind

Given how common loading roof racks on off-road vehicles is you would think there would be better info though
 

CMARJEEP

Observer
I think with the aftermarket cross bars you will be okay. Generally the factory rails are pretty stout, it’s the factory crossbars that are ********.
 

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plh

Explorer
Risk is that the RTT flies off your roof at highway speed and hits the car behind you. Call your Jeep dealer and ask about rack loading.
 

rgallant

Adventurer
@plh I am assuming you have seen this happen from overloading or just improper installation. 155 vs 150lbs literally insignificant assuming everything is in good repair, and the tent is correctly installed. If he was going with a 200lb tent that could be an issue
 

plh

Explorer
@plh I am assuming you have seen this happen from overloading or just improper installation. 155 vs 150lbs literally insignificant assuming everything is in good repair, and the tent is correctly installed. If he was going with a 200lb tent that could be an issue
OP needs to find out if it is a static or dynamic load rating.
 

G jeep

New member
I saw a flip type small RTT on a kl with aftermarket cross bars. The factory rails flexed the roof quite a bit while unfolding with no additional weight in the tent. The tent was one of the lighter ones available.
 

rgallant

Adventurer
@plh Jeep does not specify in the owners manual (no surprise almost no manual does), in those cases it is assumed to be Dynamic as that is always lower than Static. Dynamic loading affects vehicle handling as it changes the Center of Gravity and as a result is a lower number.

@G jeep interesting I found 2 and 2/3 person tents ranged from 100lbs to almost 180.
 

rgallant

Adventurer
@plh that is great I wish the rest of them would - of course dynamic is the most important but still the static would be nice to know. I sent a lot of time and emails trying to figure those numbers for a Discovery II with gutter mounts.
 

G jeep

New member
@plh Jeep does not specify in the owners manual (no surprise almost no manual does), in those cases it is assumed to be Dynamic as that is always lower than Static. Dynamic loading affects vehicle handling as it changes the Center of Gravity and as a result is a lower number.

@G jeep interesting I found 2 and 2/3 person tents ranged from 100lbs to almost 180.
@plh Jeep does not specify in the owners manual (no surprise almost no manual does), in those cases it is assumed to be Dynamic as that is always lower than Static. Dynamic loading affects vehicle handling as it changes the Center of Gravity and as a result is a lower number.

@G jeep interesting I found 2 and 2/3 person tents ranged from 100lbs to almost 180.
The process of unfolding the tent to the side flexed the roof due to the leverage of the overhang. The tent was at the lower end of the weight spectrum.
 

plh

Explorer
@plh that is great I wish the rest of them would - of course dynamic is the most important but still the static would be nice to know. I sent a lot of time and emails trying to figure those numbers for a Discovery II with gutter mounts.
I double checked the owners manual last night for the '05. It say 220 lbs while traveling for the factory rails.
 

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adaml

Active member
I don't know anything about Jeeps but I ran an RTT for quite a while (CVT Rainier Summit) on the stock roof rails with a set of Thule Aeroblades on my old 4Runner. I took that thing all over creation. I've never understood the reasoning behind having some aftermarket rack to just cover it up with a tent. With the 4Runners, every single aftermarket rack used the factor roof rail mounting holes. The roof rails themselves were solid metal so I just didn't see the benefit.
 
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