Carrying Capacity for Racks on Fiberglass Shells

A.R.E./Leer don't want to give exact numbers but the average estimate that I see in various TW threads is standard fiberglass shells have a dynamic carrying capacity of 150-170 pounds - I'll use 160 pounds in my math below.

Subtract from that the weight of:
-a Prinsu rack (55lb)
-a Yakima cargo box (50lb)
-Thule tracks (5lb)

...and you're just left with 50 pounds of stuff you can carry on the highway.

Did I do that right? I hope not, cuz that's an awful lot of money and effort for 50 extra pounds of storage. Seems like the benefit is mainly physical space, ie having space to carry a canoe etc.

Thoughts?

 

Yes. As you can see, most fiberglass shells are designed to have things in them, not on them.

Most commercial shells are aluminum, as are the camping shells that are becoming popular.

Will they likely hold more weight? Probably. But good luck trying to warranty them if they crack!

 

You’d likely get a bit more capacity out of a fiberglass shell if you install bed stiffeners but like Naveronski pointed out, they’re not really designed to carry stuff on top of them.

 

Yeah, I posted a question about this a while back in the camper shell thread. If you want a higher load capacity on top of your shell you would have to get something like the HD models from ARE.

 

I have seen youtube videos for years that Tacoma drivers have tent and stuff on their racks.... especially the fiberglass shells/toppers. No matter if they are HD or not.

No problems so far as long as you have things to secure with. Such as bed stiffeners...

 

Right, though my understanding is static carrying capacity is a good bit higher than dynamic carrying capacity, meaning stationary weight is easier on fiberglass shells than the sideways force they get when bumping along a trail or driving down a highway. Even still, I personally wouldn't put a RTT on a standard FG shell without bed stiffeners, though I know some do it.

 

It would be nice if they gave a definite number like that for the non-HD shells lol

it was kinda frustrating that they wouldn’t even ballpark guess when I called. The dealer was the only one who would give me an educated guess.

 

Agreed. After reading like 20 forums I get the sense max dynamic weight capacity for standard FG shells is around 150-170 for what that's worth.

 

And that's probably for pavement use only. I wouldnt load up a fiberglass shell umless it was designed and rated specifically to do that. They crack, they spread out they're basically not a good platform for weight. You might consider going another option like a Smartcap or alucab for that option. Just a suggestion.

 

True.

Two takeaways I have from this..

-Roof racks on FG shells are more helpful for extra space than extra weight
-If you're mounting a roof rack on a FG shell, consider the tradeoff between the roof rack's weight and its carrying capacity. All things equal if your shell handles 150 pounds you probably want the lightest quality rack that reliably handles that.

 

I don't have the warning label like the photo above your post. I only have the factory label.

Since topper usually carry about 150 lbs so the prinsu crossbars can carry 200+ lbs...

I saw a video years ago that a guy installed the rack, he stood on the crossbars and walked around.. I can't remember who it was.

 

I run a cargo box for skis in the winter and a RTT in the summer on my Leer 100xr. Been doing this for over 5 years now with no issues on or off road.

The RTT is ≈ 120lbs and we sleep 2 adults and 2 kids so the static load is in the 500lb range (people, tent, bedding, rack).

 

Do you remember if that was an HD model or not?

 

Awesome set-up and good to know! Do you just have standard Thule/Yakima rails?

 

I installed Thule tracks, towers, and crossbars. It is much more versatile than the prinsu or frontrunner style racks, in addition to being lighter.

I also have 3rd crossbar that I can run on the cab when picking up lumber or longer items.

 

Everyone has their own risk factor to weigh in on. I have severely abused my Leer 100XL for over a dozen years with absolutely no issues or complaints and I bought it used. The clear coat has gone bad but so has the clear coat on my Tacoma.
It has Yakima tracks and bars that were on the shell when I bought it. No signs of stress cracks, sag, lean or twist. Maybe I just got lucky.

Just a few photos loaded up:

 

no I don’t remember. I wasn’t paying attention to the topper, I was looking at the rack and watched him standing/walking on it.

 

lol I can’t blame you!

 

Hmmmmm. This makes me feel like I can get away with mounting a RTT on my non-HD A.R.E. cap