I have a 91 Surf with no factory roof system, which means ill have to drill into the roof to attach racks. How much weight will the roof carry?

Ideally i would like to put a RTT on top of it, but i doubt that would be possible without reinforcement. However what about a roof rack that i would put firewood ontop of? Does anyone have experience with this?

 

Consult your owners manual? You'll find a number in the 75-150lb range. We know from experience you can quickly exceed this with a roof top tent occupied with two adults, but that's a static vehicle in a dynamic state you need to be aware this drastically changes your center of gravity which of course alters the handling and tendency for body roll which increases the odds you'll end up wheels to the sky..

It's an SUV ment to haul people not a shed load of wood on it's roof, get a trailer or put your wood in the cabin.

 

Or a first-gen
Remove the roll bar and cap for vertical clearance

 

Is your 91 surf the first or second generation?

 

1991 Surf is the SUV, aka 4runner, not a truck/pickup which makes it a 2nd gen. Has a steel rear section not a removable top.

Surf = 4runner, enclosed rear cabin
Hilux = pickup bed, open rear cabin

Might have that backwards but 90% sure.

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Im in the middle of building a new custom roof rack. I bet I can load mine up to 250 lb easy. If I specifically needed more capacity I would design and mount with that in mine. If you need to I bet you can go much higher yet. Driving would be effected obviously.

 

I have made it this far. Trying to decide on mounting setup.

 

I have a 91 4R with factory roof rack. I've loaded it with roughly 200 lbs of lumber a few times no problem. I try to distribute the weight as much as I can and there's some flex in the rails but I've never had an issue. Definitely more body roll though.

I've also set up a chair on the roof itself, not the rack, while hanging at the lake. Not even any dents in the top. To be fair though I'm not a big guy. These roofs seem to be able to hold their own.

That being said, I second what others have said, try to keep the weight in the cabin, or at least as low as possible. Don't stack anything too high. It'll risk not only more body roll but the possibility your load will tip right off your roof around a corner.

Look into a hitch mounted rack if you don't want a trailer. You can pick up one rated for 500 lbs for around $50-60.
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There you go. The weight limit for the roof would be more of a safety issue, not mechanical load-bearing capacity.
If installing roof rack where there is no factory mounting points, I would mount as close to corner where roof meets vertical walls because that would be the most rigid part.

Correct. Second-gen Hikux Surf. (First gen is same as first-gen 4Runner)

 

I bolted one through the roof framing years ago, held up for years of construction work, ladders, wood, you name it. RTT would be no problem if you do it right. Pull headliner, drill, bolt heads through roof framing and roof, silicone caulk then large washer, then smaller on roof, then nut, then another nut halfway up bolt to mount whatever (I used C channel), and another nut on top to lock it all down- spanning to another nut on opposite side. 4 holes in roof. Had pics at one point but then Photo˟˟˟˟t'it up for the www. When you drill through roof framing there's a support divot right near roof edge, I drilled just inboard of this.

 

Oh yeah, Also see ChefYota4x4's install of t-slot rail / c-channel.

 

I fixed most of the pics in that thread https://www.yotatech.com/forums/f88/.../#post51714678

 

a lot of it is going to depend on your skill set IMO.
I extended the factory roof rails on my 94 using 1/4" nutserts every few inches. I don't plan on carrying a ton of weight on the roof just because the truck is a pig already when it comes to mileage/acceleration and sways like a tree in the high wind. Increasing the COG as mentioned doesn't help

 

RTT, (?)
NOCO, (?)

I expect better from the internet! Don't use, or atleast explain your abbreviated anachronisms..



Whatever's..

The essential point is weight up high is bad for handling, and the vertical surface can carry more load than the horizontal fiber or steel sheets due to sheer and load stress. Assuming you bridge the inner and outer surface. Triangles are Good!