Quote Originally Posted by wildeny View Post
(How do they come up with the frame size of 44, 47, 50 cm etc? Based on what? )
The "frame size" is generally the measurement of the seat tube - and it can be very misleading. Different frame styles can be the same "size" and really be very different. Take for instance cyclocross bikes - the bottom bracket is higher on cross bikes so a 44/43cm cross bike is more like a 48 or 50 in a road bike....

In the end you really need to look at the whole bike - just focusing on one measurement (especially whether or not you can stand over it - too many bike shops fit that way ) can lead to an ill fitting, uncomfortable bike that you won't want to ride.

Many little women end up with bikes that are too big because they can stand over a larger bike than they really need and the shop wants to sell what's on the floor rather than special order an extra small one...... If you cannot keep a comfortable bend in your arms when you are riding, the bike is most likely too large. And its not only comfort you are sacrificing if you have to ride with your elbows stiff - you also have less control and less power!