Crossbar and rooftop carrier question

So, I have a Thule Force XT cargo box that I am going to need to use for a trip in June.

Wondering if anyone has used something similar with aftermarket bars (like LFD, Victory, etc...not Thule or Yakima bars). Most of them look like they sit pretty low so my concern is getting the cargo box feet clamped around them.

It sounds like some have had issues with the factory bars, others say they are fine. I do not have any crossbars yet so there is an opportunity to upgrade, just want to be sure there is enough room under them to use this box.

 

I have not, but when I was looking at options like the Victory and Artec flat bars, I assumed I would be able to bolt through the slots instead of using a clamp that went under and around

 

Yeah, the cargo box already has the clamps (and technically, it belongs to my gf so if I modify it, I need to be able to reverse whatever I do so she can use it on her car).

 

I think if you have this style of feet (imbedded pic) you can easily attach it to the flat bars with some bolts/washers/nuts by just not using the clamping feet, which are easily removable, and dropping the bolts through the gaps with large washers or a square plate with holes drilled into it. But if you decide to not go that way, I think you would be fine with clamping them to the OEM cross bars, or something like the Rhino Rack square bars



I've had Thule clamps fail on me in the past, so I generally just try to bolt any of their products to my racks instead.

Wish I had better experience to share.

 

I have a similar Thule cargo box. The LFD bars fit.