Correct Bike Size Cannondale

Every bike has a different geometry and each brand has its own convention for sizing their bikes. Some publish the length of the seat tube (this can be either Centre to Centre or Centre to Top) as the bike 'size'. Others use the length of the top tube to determine bike size. 

The following chart provides a rule of thumb approach to determine your bike size based on your height. This is a simple approach to a complex situation, but it is accurate in the majority of cases.