Bike sizing is the process of taking the measurements of an individual and applying those specific measurements to match a person to the correctly sized bike frame. Depending on where you go to get measured (or if you are doing this at home), you may find that shops, fitters, or a multitude of websites provide you with numerous ways to discover the correct bike size. One of the earliest methods was a formula applied by French Coach and former pro cyclist, Cyrille Guimard based on the inseam. Greg Lemond later used and popularized this method of multiplying the inseam measurement by .883 to determine saddle height and frame size.

A similar methodology remains in use today by some bike shops who will measure your inseam and have you stand over a bicycle top tube to obtain the proper frame size. If you use the ubiquitous Google search method, you’ll likely find a chart that suggests the best size for you based on a few measurements like you were purchasing a t-shirt or a hat (you are less likely to experience an injury from hat or t-shirt which is why bike fitting is vital).