I store my ebikes in the garage when home; but, I have traveled with my two fat tire Radrovers (last trip was to Grand Canyon/Sedona in Nov/16). I ended up getting the Dual bike cover from Formosa Covers for 1-2 bikes, Amazon, $46+16 shipping:
https://www.amazon.com/gp/product/B000WENDUS/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1
It completely encases the bikes, made for hwy speeds and harsh weather, large enough for two fat tire bikes, has plenty of straps to tighten down the cover, and has translucent panels near the front/back wheel for tail lights to shine through. I was able to put the cover over both bikes and the bike rack. Only the bike rack arm that attaches to the hitch was uncovered and there was string to secure that end. I can fold small enough into its carry bag to take up about the same space to fit inside a paper grocery bag with some room to spare.
I purchased the cover just in case we had a rain or snow on the +5 hr drive and cover the bikes at the hotel if we couldn't take them into the room at night (out of sight, out of mind thinking). No rain or snow the whole trip; but, used it every night to cover the bikes (and keep the morning frost off at the Canyon).
The downsides to this cover are:
- the translucent panels help; but, I still worried during the day if my brake lights were clearly visible in heavy traffic. Added AUX 4-way light that plug into my hitch wiring harness for added safety.
- no way to lock the cover to the bikes or hitch. might have to put a 20 foot long cable with lock to keep someone from taking it at night.
Probabily common to all travel covers along with one I have:
- covers license plate, back-up camera, back-up lights, and blocks rear view mirror visibility. Mostly used side view mirrors when driving with cover.
- might have to check local laws about driving with your license plate covered
- felt like I had a parachute on the back of my 11 MDX when driving with the cover at hwy speeds. Might feel different on another vehicle.