Questions about getting the right frame size (Dahon Jack)
Hi, I'm brand new to folding bikes, and I live in an area where the nearest shop that carries *any* type of folding bike is about 280 miles. Currently my riding is 50/50 gravel/trail and street, and I've been looking at the Dahon Jack. I like the 26" wheel size. Portability is important, but more "I want to fit this in my car" than "I want to carry this comfortably on the bus" important. So far the only bike I've found that seems to fit my riding & budget requirements is the Dahon Jack.
I'm about 5'9", and from what I understand all the Jack models have 26" tires with different frame sizes (16", 18", and 20").... What exactly does the frame size measure? The recommended for my height is 18", but I'm used to riding full-size bikes, so should I be looking at the 20" frame?
I'd appreciate it if someone could give me more insight into exactly how these frame sizes work in the real world