Empty roof top carrier - ok on our trucks?

So, I managed to snag or of these today:
http://www.homedepot.com/p/t/203670...CJ3cmefEeOt5_J1rARu_gy5r3_yXis3_0_0_0&cj=true

Here is my quandary.. I would like to keep it on all season, as I anticipate using it over weekends going up to the mountains. Problem is, the instructions says that you need at least 50lb of weight in there to do highway speeds.

Given that this is sitting far back (on top of my camper shell), is this really something I have to worry about? We had a space case on our family van growing up, but I don't remember it having weight inside. I know I can throw a 5 gallon jug in there, but it feels like an unnecessary pain...

Any thoughts?

 

I leave my Yakima Rocketbox on my rack sometimes when I'm too lazy to pull it off; it's bad for the gas mileage but other than that I've never had an issue with it. That's a hell of a deal on that box too.

 

Have a Yakima Skybox21 on our other car, it weighs 62lbs by itself..
I've never heard of a required load limit before.. Definitely not in my Yakima instructions..

 

Baja - How much of a hit did you take?

vicali - Like you, i had never heard of it. Growing up, we had a SpaceCase on our van... can't say i ever remember us having a dummy load in there.

To be safe,i think i will throw a water jug up there, as i am curious to see the impact. But it is a bummer

 

Same with the Thule box I use on our MDX. I've driven with it empty plenty of times....no issues.

 

Maybe where the clamps are connected to the box are weak and it needs weight in it so there is no vibration around there to rip the box off the clamps. Could be cheaper material then Yakima and Thule. My Yakima will stay on my wife's car for weeks at a time. Never had an issue with it.

 

Great price on that. I looked at it and thought about putting rails across the bed and mounting it there for long trips instead of on the roof but I couldn't find any in stock in my area at HD.

 

That is something of the feeling I had. Since I had it kicking around, I threw a 20lb bag of rice in the front.. 20lb wont kill me for sure. Now to see if the mpg hit is worth the convinience oh always being ready..