Weight Capacity of Roof or Racks

[Jwatt38]

Suburban owners. I got a '93 Silverado Suburban.

How much weight capacity can the roof hold? Let me be more specific. I've read the factory-installed roof rack can hold ~200-250Lbs.... I think. I've seen racks advertising 500 lbs capacity.... is that attaching to the factory rails? Cause its the crossbars that hold 200 lbs correct?

I want a rack that I can climb on, shoot from (photography/videography). I'm a big dude so the factory set up won't do.....

I can have one custom made, but am I connecting to the factory rails or connecting to a sturdier point.

Please help me understand the structural strength of the roof.

 

[billiebob]

I've done a few of these, never on a Suburban, but I always remove the factory crossbars and figure a way to attach to the factory rails. I've never had a problem and I weigh 250#. I try to use the entire rail to distribute the load, not just attaching at 4 points. Sorry, no pics.

 

[nitro_rat]

I put an extra set of factory rails on a 96 I had years ago. A buddy of mine had a car lot and I pulled them off a Tahoe that he got back wrecked. Hauled a LOT of weight up there, far more than 500 lbs on several occasions...

The factory rails do bow down and touch the strips on the roof when loaded down heavy, maybe not a great place to shoot video from. The most I had up there was probably 2/3 of a full bundle of 2x4 studs.

That truck was lowered to make loading the rack easier and to increase stability when loaded. I probably wouldn't recommend that setup today, I was probably 19-20 when I did that...

 

[CrazyDrei]

Jwatt38,

To answer your question: YES.

My current setup. When I drove to Alaska and back I had 3 full size spare tires (200lbs) 2 trailer tires (100lbs) 30 gal of gas (180lbs), camping chairs, camping supplies and other stuff (200lbs) thats on top of the weight of the cross bars, ski box and cargo basket (150lbs).

Partially loaded.

I run stock factory rails, not the fat Z71 rails. 4 66" Yakima cross bars, 4 Yakima RailGrabs that are positioned as close to as I possible get them to the factory locations where the roof rack attaches to the roof of the Sub. Crossbars are spead out to distribute the load as evenly as possible and two factory cross bars are positioned in two areas where I needed more reinforcement. On top of that sits a Thule ski box and a Rola Cargo basket with two extensions. It's big enough to fit a twin size mattress.

I went with the lowest and strongest, cheappest, most versatile and most durable roof setup I could create. I can comfortably carry 1,000lbs between my basket and ski box. I carried nearly 1,000lbs for 12,000 miles when I drove to Alaska and back, and that was not a paved highway. Roof and the rack are holding up great.

So to answer your question again. Factory rails will hold over 1,000lbs. Factory cross bars are only rated for 150lbs. So you can build a custom rack or platform or you can strategically place sturdier yakima/thule/ebay cross bars and build a platform for you to shoot photography from. You mentioned that you are a big dude, well if you can make it up on the roof it will hold.

The reason the roof can hold so much if you distribute the load is because it has reinforcement beams where the factory rack attaches to the roof. This is a picture looking up on the ceiling from behind drivers door. Sunroof is the hole on left. The beam is to the left of the cut I made.

The cut is in the middle of the blue tape for reference. You can see that there are three sets of pads for factory roof rack rails, middle of which is bisected by the tape line.

Hope this helps. And good luck with your roof rack project.

 

[rayra]

The LT rails are continuous so the weight is spread over a large area.
My Z71 rack has very large plastic 'shoes' at the four corners, as well as two intermediate smaller feet along each side. And the side rails are very beefy extrusions.
I've never looked up any rating capacity, but I would expect it to be relatively high. There are also the six longitudinal ridges in the roof skin, which on the Z71 are also topped with some sort of thick plastic rail covering.

/I wound up hanging a solid deck from mine, mostly to shade as much of the roof as I could, wound up putting a panel on there, and intend to add another.

eta here's a shot of some recent work to re-wire the rooftop solar connection. This is the back left rack mount shoe, the side rail is the hollow extrusion running off the lower left of the image

 

[s.e.charles]

Suburban owners. I got a '93 Silverado Suburban.

How much weight capacity can the roof hold? Let me be more specific. I've read the factory-installed roof rack can hold ~200-250Lbs.... I think. I've seen racks advertising 500 lbs capacity.... is that attaching to the factory rails? Cause its the crossbars that hold 200 lbs correct?

I want a rack that I can climb on, shoot from (photography/videography). I'm a big dude so the factory set up won't do.....

I can have one custom made, but am I connecting to the factory rails or connecting to a sturdier point.

Please help me understand the structural strength of the roof.

someone should introduce "static" & "dynamic". standing on the roof rack or braking from 60 mph with half ton up there may introduce different stresses.

 

[jaeggernaut]

@CrazyDrei, i was searching the net about this and came across this thread.
what you said puts my mind a bit more at ease but I can't get a straight answer from ford, the dealer or the rack maker. maybe you can give me your thoughts.
i have a 2019 expedition. roof rack capacity is 200lbs UNLESS you have the moonroof (which we do). then the limit goes down to 125lbs. i have a 160lb rooftop tent (which I bought and had shipped to me before I bothered to look at rack ratings.. ?‍♂️).
i can get new crossbars from a third party (thule or yakima) that has a 160lb rating but if it wasn't the actual factory rails that was the weak point, why would the rating be different between having a moonroof or not?

thanks in advance.

 

[CrazyDrei]

@CrazyDrei, i was searching the net about this and came across this thread.
what you said puts my mind a bit more at ease but I can't get a straight answer from ford, the dealer or the rack maker. maybe you can give me your thoughts.
i have a 2019 expedition. roof rack capacity is 200lbs UNLESS you have the moonroof (which we do). then the limit goes down to 125lbs. i have a 160lb rooftop tent (which I bought and had shipped to me before I bothered to look at rack ratings.. ?‍♂️).
i can get new crossbars from a third party (thule or yakima) that has a 160lb rating but if it wasn't the actual factory rails that was the weak point, why would the rating be different between having a moonroof or not?

thanks in advance.

jaeggernaut,

Can you take a post a picture of your roof/roof rack/sunroof, looking back from the front of the Expedition?

Manufacturer's recommendations are based on liability. It is not necessarily the actual dead weight rating of the roof rack or the roof but the safe load of the weight on the roof rack in all conditions of the vehicle's abilities. How much weight can you put on the roof rack for the Expedition to still meet all the NHTSA requirements which includes emergency maneuvers and top speed performance.

Moon roof weighs approximately 50lbs give or take and raises the vehicles center of gravity thus taking away from the load manufacturer can recommend on the roof rack. If anything more than 200lbs w/o moon roof is the most weight that Ford will stand behind it makes no sense for them to make a roof rack especially cross bars that will hold more weight than that, once again liability. This is my assumption for the weight ratings.

Now to get back to your initial question regarding the RTT... You have a couple options depending on what you plan on doing. Both of them will require at least one more cross bar and hopefully two more.

1: Add two more OEM factory cross bars. I am sure you can find them for really cheap if not free on craigslist, ebay, local pic-a-part or FB marketplace. Spread them so that they are over or as close to actual roof attachment points as possible to distribute the load most evenly. This will be more than sufficient to attach and keep the RTT on your roof.

2: 2 sets of either Yakima or Thule cross bars, attached to the factory rails. This will be a much stronger and sturdier setup and will help you sleep much more comfortably on the roof.

I would start cheap, with 2 more OEM cross bars, mount the RTT and see how it works. See what you like and dislike about it. Drive around, open it up and crawl in there in your yard and decide if it is good enough or if you want more stability and go from there.

Hope this helps, have fun and most important post some pictures of the progress!

 

[jaeggernaut]

thanks for your input. going to go for the 2nd scenario you posted. cracked moonroof be d@mned!
was hoping to add a 270 awning too... but looks like i even maxed out the crossbars (more accurately, the thule attachment 'legs' for the bars).

if i crack the moonroof... I'll post it. ?

(the pic is the factory bars. still need to pick up the thule ones)

jaeggernaut,

Can you take a post a picture of your roof/roof rack/sunroof, looking back from the front of the Expedition?

Manufacturer's recommendations are based on liability. It is not necessarily the actual dead weight rating of the roof rack or the roof but the safe load of the weight on the roof rack in all conditions of the vehicle's abilities. How much weight can you put on the roof rack for the Expedition to still meet all the NHTSA requirements which includes emergency maneuvers and top speed performance.

Moon roof weighs approximately 50lbs give or take and raises the vehicles center of gravity thus taking away from the load manufacturer can recommend on the roof rack. If anything more than 200lbs w/o moon roof is the most weight that Ford will stand behind it makes no sense for them to make a roof rack especially cross bars that will hold more weight than that, once again liability. This is my assumption for the weight ratings.

Now to get back to your initial question regarding the RTT... You have a couple options depending on what you plan on doing. Both of them will require at least one more cross bar and hopefully two more.

1: Add two more OEM factory cross bars. I am sure you can find them for really cheap if not free on craigslist, ebay, local pic-a-part or FB marketplace. Spread them so that they are over or as close to actual roof attachment points as possible to distribute the load most evenly. This will be more than sufficient to attach and keep the RTT on your roof.

2: 2 sets of either Yakima or Thule cross bars, attached to the factory rails. This will be a much stronger and sturdier setup and will help you sleep much more comfortably on the roof.

I would start cheap, with 2 more OEM cross bars, mount the RTT and see how it works. See what you like and dislike about it. Drive around, open it up and crawl in there in your yard and decide if it is good enough or if you want more stability and go from there.

Hope this helps, have fun and most important post some pictures of the progress!