I am often asked how to select the right size bicycle frame.  Unfortunately many bicycle stores are more interested in selling what they have in inventory than they are in getting the customer the correct size frame.  Sadly many of those selling bicycles are not serious riders or students of the sport of cycling.  I have heard sales people tell customers that a particular bicycle might be too much bicycle for them.  They must think it has a mind of its own and can bolt out of control.  If you are new to serious cycling I suggest you look for a used frame.  Remember, the wheels and components are, in my opinion, more important than the frame.  Also, do not buy a road bicycle with head tube and seat tube angles more than 73 degrees.

Since there are many opinions for selecting a frame I believe that the most scientific formula was developed by the Renault Division of Physiology and Biomechanics.  Simply put, in your stocking feet, measure your inseam from your crotch, using a slotted Dow Rod, to the floor.  If you do not have a Dow Rod, press the tape as high in your crotch as you can.  This measurement needs to be taken in centimeters.  Now multiply that number by .65%.  The result is your frame size, measured from the center of the bottom bracket to the center of the top tube.  For example, a rider with a 91cm inseam x .65%  =  59.15cm.  Round that off and you have a 59cm frame.  Remember you want to ride the smallest frame size that your measurements will allow.  Weight and handling are improved if you follow this advice.  Also, riders that are over 6' tall may need to add one or two centimeters in order to get a longer top tube.  The top tube length should allow you to have a handlebar extension of no more than 14 centimeters.
 
With this exercise you are now ready to be fit on your bicycle.  Watch my Blog for Bicycle Fit.