In order to use these crossbars with a Pace Edwards tonneau with Explorer Rails, you'll need to use the Rhino Rack RLT600 Legs, and then you'd be able to add any Rhino Rack accessory that's compatible with the Vortex Bars. That being said, in our experience with the Pace Edwards Explorer Rails, the RLT600's t-slot nuts were a hair too wide for the Pace Edwards t-slots, so you may have to grind them down or get slighter narrower t-slot nuts locally. If you need further assistance putting together a rack system, give us a call directly at 623-434-5277 or email us at [email protected]