I just did ~36 miles/55 km. on my Curve D3, in Burgundy, France, almost exclusively on bike paths, some of which were hilly, with an elevation gain overall of about 650 feet/200+ meters. I'd be lying if I said I would not have preferred to be on my full sized carbon frame road bike, and it sure would have been great to be in better physical condition than I am at the moment. I might add that I'm no "spring chicken."

Nonetheless, I did this ride in a little more than 3 hours, with a couple of short rest stops, and there was some wind, mostly in my face.

What I'm saying is that this simple 3 speed IHG 16" bike is quite capable, and I was able to do a pretty significant ride on vacation on this little "clown bike." I wouldn't hesitate to buy one of these again. I'm sure it is not as nice as a Brompton, which would cost 2.5X as much, nor does it fold quite as small. It is, however, a pretty good, solid, bike that is available for a decent price. The Big Apple tires that come with it really cover up a lot of the flaws this bike might have, given its size, and produce a pretty smooth ride for what it is. Even going downhill at more than 20 mph, I never felt like I was going to crash, or that the bike was unstable.