Please excuse the newbie questions, but I need some help. I was wondering what some of you look for as far as fit when sizing up a new mountain bike? I heard some say to look down at the front hub (not sure) while seated and if the handlebars eclipse the front hub that is a crude way to start? If the front hub is visible just below the bars would a shorter stem be a consideration? I am trying to arm myself with as much info as I can so I am more confident that the LBS I choose is giving me honest and sound advice. Thanks in advance.