Loaded touring bikes have a longer wheelbase and wider range of gears than do triathlon and racing bikes. This makes the tour ranging bikes smoother riding and easier to pedal up steep hills. The sport touring bicycle is a cross between a loaded touring bike and racing bike. More responsive than a loaded touring bicycle, it still has a wider gearing range than a racing bike. It's a good choice for all-around recreational bicycling.
Bikes come in many frame sizes.
To get a bike that fits you, start by straddling it. If there's about an inch of clearance between you and the top tube, you've got the right frame size. The seat should be adjusted so that when you are sitting on it your leg is straight when your heel is resting on the pedal at the bottom of its circle. Finally, check the distance from saddle to handlebars. When you buy a bike, you'll find there are hundreds of accessories and lots of bicycle clothing available to go with it.