I’ve not been keeping MPG records, and our CI travels are highly varied with mountains, flats, ferries, etc. Basically we’ve not had enough experience to properly answer your question.
With that disclaimer, here are a few thoughts & opinions! That’s all I got!
* I think the MPG hit comes with cross-bars. If you’re carrying watercraft or bicycles or a cargo box I’d guess you’d notice an impact.
* The ARB awnings only present a few square inches to the airflow. That seems like very little.
* Likewise, risers like mine present no airflow resistance… well, a wind-tunnel test might show differently if the airflow is already messy, but if the apparent wind is coming fore to aft the risers are nothing.
* Don’t go for Yakima round bars. They are less popular now, no need to pursue them. For me, I have ski racks, canoe racks, bike racks, towers, & other attachments based on this older tech. If I didn’t have that existing investment I’d get…
* If Yakima, get the newer Aero bars. Less wind resistance, better product support, current line of accessories, etc.
My roundbar system is almost completely removable. The towers come off, only leaving the anchors, small and don’t stick up much from the CI roof. Everything I put on them is unboltable and removable. My point is that if you don’t like the risers you can take them off. Awning? The same. There’s a lot of flexibility in these systems.
