MAKING SURE YOUR BIKE FITSThe following are general tips in sizing a bicycle for comfort and efficiency of riding. It would be recommended to have your bike properly sized by a professional bicycle shop at the time of purchase.
Frame Size. Getting a bike frame that matches your body size is one of the most important aspects of fitting a bike. If the frame size is wrong, you probably won't be able to adjust the seat and handlebars enough to compensate. When straddling the bike with both feet on the ground, there should be at least 1-2 inches between the top tube and your crotch. If there's less space, you're going to hurt yourself at some point when you hop off the seat to stop. If there's a LOT more than 1-2 inches, then whether your bike will fit will depend on how far up you're able to move your seat and handlebars.
Seat Angle. You may be tempted to have your seat tilt down to relieve pressure when in the seated position. If your seat tilts down, gravity will be pulling you off the front of your bike and pushing you into your handlebars, and you'll place a lot of stress on your fingers, wrists, arms, and neck to keep you pushed back onto the seat. Keep your seat level, or even tilted one or two notches up. If your seat is uncomfortable when it's level, it may be too high. Try lowering it. If you're riding for more than 1 hr. at a time, you're liable to get sore no matter what.
Seat Position (front to back). The nose of the saddle should be behind the bottom bracket. If it's above or in front of the saddle then you have to pedal directly underneath or behind you, robbing you of efficiency. Also, in normal riding position with the pedals parallel to the ground, your front knee (from almost the front edge) should be directly over the pedal spindle (the middle of the pedal). This helps assure an efficient down stroke and helps prevent knee pain.
Handlebar Style. Mountain bike- or cruiser-style handlebars allow you to sit upright without hunching over your handlebars. Hunching over is uncomfortable, reduces your visibility, and makes you more likely to fly over your handlebars if you have to stop quickly. If your bike has old 10-speed style handlebars, you can get a bike shop to put modern handlebars on it without having to trade in your whole bike.
Handlebar Height. Your handlebars should be at least as high as your seat, or even above it, so you can ride upright. If your handlebars are lower than your seat you'll be pushing on to your handlebars placing more stress on your wrists, arms, neck, and back. Most handlebars can be raised by loosening the screw on the top of the handlebar stem with an allen wrench a few turns and then tapping it with a hammer to release the mechanism inside. There are vertical hash marks in a ring around the handlebar stem that indicate the maximum you can safely raise the stem
Information obtained from www.bicycleuniverse.info.
Still not sure if your bike fits you correctly????
Take it to a local, professional bike shop where they can help you make the proper adjustments!!!