Here's one!
And to answer your question:
Nobody uses Thule or Yakima cargo boxes for expedition applications because they'd fall apart if they had anything in them and were subjected to the kind of vibration they'd get off road.
[edit] OK some people use em with no problems per the previous two posts [/edit]
So why do I use one?
Well, sometimes I just need more capacity than the bed can hold. And I bought it for my skis anyway...
But I just said
"they'd fall apart if they had anything in them and subjected to the kind of vibration they get off road.". (In bold face type, even)!!!
Yeah,
I still think that, so I didn't take any chances with the $150 Thule cargo box I found on craigslist. I just needed to
reinforce it with some 1/8" ABS plastic sheet I had on hand...
Like all Thule boxes, the bottom has ribs for strength:
The ribs are about 1" deep so I boxed the entire rib layout with 1" wide 1/8" ABS plastic. Then I sandwiched the bottom of the cargo box between two layers of 1/8" ABS plastic sheeting using ABS Cement and aluminum screw posts.
Here's the bottom:
And here's the inside:
This shows the 1" boxing that's barley visible from the side now.
I added a 2nd layer of 1/8" ABS plastic where the box rests on the rack cross members so the Thule cargo box bottom is about 3/8" here to distribute the shock of vibrations.
This cargo box weighed about 35 lbs before and about 50 lbs after.
It has held up for 7 years now with mixed desert and winter use. So I'd say find one cheap, spend an afternoon making it trail worthy and enjoy!