Anyone have experience with rooftop cargo bags?

I'm possibly looking to put one on my bed rack for camping/wheeling

My only real requisite is that it is waterproof. Not just water/weather resistant.

I would also like it to be a 36x36" base.

I've read about the Rain-X one but it seems to have a lot of neg reviews about the zippers, etc.

The other one I read about is the Rightline bag.

Does anyone have any experience with a cargo bag they recommend?

 

Then can anyone suggest what other forum I can post this in to get some feedback?

 

I have an Altius one I got at Walmart years ago. It's a good bag and pretty good in the weather. The only way you'll find a soft bag that is actually waterproof is if you find one that is PVC coated. Even then it's possible to get water through the zippers if it's really heavy rain.

My solution if I know I'm traveling through heavy rain is to wrap the gear in a small tarp and then store it in the bag. The bag does a pretty good job already so the tarp is just added security.

As for zippers, if you can find one with YKK zippers you'll be good. YKK's don't separate or bind, unless you damage them.