Normally when we go places we don't worry much about rain, We live in Colorado. But we do sometimes go out of state. Should I be concerned about having our 2 bikes on a hitch mounted bike rack at back of SUV if we hit rain or other precip? These bikes are electric....
Do they require covers?
As a general rule they do not. The issue come if the controller gets "submerged".
If your bikes get submerged on your car then I'm guessing you have bigger issues to worry about ;D
Throw a sandwich bag on the speed adjustment and on the lcd screen and hold it down with hair tie or rubber bands. or you can throw a tarp over the bikes.
I think it's a good idea to have a cover. I'll have a video out in the next week on the one from Pro Bike Tool. It's on my accessories list under 'Bike Racks/Storage' here: https://www.radowners.com/index.php/topic,104.0.html
I got the XXL and plan to see how the coverage works for two ebikes.