We have 2 electric folding bicycles we keep in the basement of our coach, Max speed by law is 20 mph or they have to be licences, We ride our at assisted level 2 easy peddling we can average about 15 mph or about 4:20 per mile. We get a range of about 25-30 miles on a 6 hour charge. I like the fact that they are out of the way and the only time I am messing with them is when we are going to use them.
Note our bikes are the cheapest ones we could find they were under $500 each.
I bought one rode it for 300 miles then bought a second one. They have had minor adjustment and poor assembly problems, still not sorry I didn't go with the $1500-$3500 alternitives.
