I guess I'm a wimp....
Maybe it's the geometry of the bike, as I always feel like I'm not in the right position when i try to push it on my Coda. But, most likely, I'm just weak! I've certainly been up to 20 mph, but I pretty much stopped looking at my average when I ride the Coda. I mostly use it to do errands or ride on a bike path, go out to eat, etc. Maybe I should ride it more, to get stonger .