This guide is broken into three parts
1. Frame Shapes
2. Frame Geometry
3. Wheel Sizes
The bike frame should be the first thing you look at on a bike. This frame will dictate how you mount and dismount your bike as well as your riding position, which will greatly impact how comfortable you are, especially on long rides.
Step Through - This shape lends itself to easy access. If you have trouble swinging your leg over the back of a bike or are planning on riding in clothing that restricts your ability to do this, a step through frame is the perfect way to go. These frames come in various configurations from low step options allowing for very easy access, to what is known as the trapeze frame which trades off some of this ease of access for frame reinforcement (see both models below).
Crossbar / Hard Tail - the most widely reconsidered bike frame, the crossbar comes in many different variations. This frame requires you to mount it by throwing your leg over the rear wheel which limits it to some for accessibility reasons. Aside from this drawback, the crossbar generally provides a very stable platform and is a suitable frame choice for commuting, rail trails, trekking and mountain bike applications.
Full Suspension / Soft Tail - These bikes are generally very similar to the crossbar or hard tail frames however offer a suspension system under or just behind where you sit. This suspension system generally adds to the overall price of the bike however gives unparalleled comfort and vastly adds to the bikes off-road capability. A full suspension frame is ideal for anyone who is wanting a very plush ride offroad or anyone who is looking for a serious mountain biking machine that will look after them against their better judgement (don't worry, that's generally us in store too).