Please don’t do this. You are going to create a sail for your vehicle constructed from your beloved bicycle. This will add to the unsupported load of your hitch with the added drag and strain the parts of your bike rack not designed for a load in this vector. Even if it doesn’t break anything, it will at best reduce your gas mileage.
Your bike doesn’t need this at all. It can handle wind, rain, and even bug guts. I have traveled to CO, AZ, AR, and PA with my precious Ripmo and it’s been fine. Save the money and invest in a proper chain lock to secure the bike from theft which it is way more susceptible to.
🙂