If you want your slower friend to keep up, this is an excellent option! Great for the flat streets of Denver, but it's really heavy and only has 7 gears, so you might want to avoid the mountains. I've transported it on the back of my sedan with no issues, but this could easily result in disaster. I think this should fit a wide range of heights as long as the taller person rides in front. Longer rentals available ($60 for a week, $120 for a month). Helmets, lock, tools included.