Hi ~ I'm a roadie who is just starting to look at entry-level mountain bikes for riding trails around our neighborhood to stay in shape over the winter - nothing too long. Anywho, my question is about sizing of mtbs. My road bikes are size 46cm (Aegis) and 17.5" (Terry), which are both the second-to-smallest WSD sizes for those particular models. I am 5'2" with approx. 28" inseam. Which mtb sizes should I be looking at to start? 13-14"? And are effective top tube lengths longer on mtbs than on road bikes? I've looked at the geometry for a few bikes (Specialized Rockhopper, for one), and all the top tubes (effective, so measured horizontally) are over 20" (even for the very smallest size women's bike), where my road bikes are ~19". Is this going to be a problem or does it work out just fine on an mtb? I don't want to have to buy a kid's bike!!

Thanks so much for your help!

Emily