I got a small Thule rooftop tent - weighs about 100#. I have the Yakima landing pads which attach to the factory roof rack rails, and which hold the towers that hold the Yakima rack round bars. The tent is attached to the bars. It all seems strong enough but I noticed that when I put my weight on it, if I look closely I can see a slight flex in the 4runner’s roof metal at the points of contact where the landing pads attach to the factory rails. Has anybody else noticed this, and/or is it issue? The metal doesn’t permanently bend or warp; it’s just a little flex under the load and it goes away as soon as the weight is off. My concern is that the metal will be flexed like that for 8+ hrs while I’m sleeping. Can that cause any permanent damage?

Also I weigh around 180#, so not huge or anything.

Similar to a spring, it will likely only sustain wear/damage through cycling, not static pressure.
There are some slightly involved ways to reinforce the roof from the inside, but many people
have used a reasonably sized RTT on their 3rd gen without such measures.

3rd Gen 4runner Roof Reinforcement

Reinforcing the Roof

Hope that helps!

Technically you should be good up to 300lbs no matter the situation and twice that static.
Flex doesn't necessarily mean there is something wrong or weak, more likely its part of its structure/design. Just like how large bridges are designed to flex/move to improve there over all durability and structure.

Ok thanks you guys. That’s good news. I guess I could add more Yakima bars to distribute the weight more if I get concerned about it.