It is close to impossible to fit someone for a bike without seeing them on the bike. It is a good practice to visit two or three good bike shops and get two or three opinions on fit.
As a general rule, bike shop's are staffed by young males who, on their days off, pretend to be Lance Armstrong. They buy bike's that are waay too small, and ride with the handlebars three or four inches lower than the saddle. An okay position for a Pro. A terrible position for recreational riders.
An ideal bike fit allows:
- your leg to be almost, but not quite, straight when the saddle is properly adjusted. There should be only a slight bend in your knee when the ball of your foot is on the pedal, and the pedal is at 6 o'clock.
- the handlebars to be as high as the saddle, after the saddle is properly adjusted for height. Pro's don't ride with their bars that high...but you are not a Pro. Riding with your hands at the same height as the top to the saddle take pressure off your privates, and off your wrists and hands. It also reduces neck and back pain.
- allows you to stand at a stop sign, with both feet flat on the ground, without the top bar of the bike pressing against your crotch. I like "tall" bikes, so some of my bikes have top tubes that lightly brush against my crotch when both feet are flat on the ground. Most shops aim for at least an inch of clearance between the top bar and your crotch while standing over the bike.
If a bike is well fitted, your back should at about a 45 degree angle to the road with your hands on the bars in your "preferred" position. Some recreational riders prefer a bit higher back angle, but avoid sitting straight up, in the old Raleigh three-speed position. Sitting straight up puts a lot of extra weight on your rear, and will be uncomfortable on a long ride. When a bike fits "right", your weight is balanced between your rear, feet, and hands, and you can easily come up off the saddle while riding over rough pavement.