This page will explain how to get correct sizing for road bikes.
When you are a beginner to cycling getting the correct sizing for your bike is key.
The best sizing for road bikes has two components.
A small vertical measurement for bike stiffness.
As well as a horizontal measurement promoting a relaxed, stretched out position.
To get the best size for a road bike you first need to get the most accurate measurement of your inseam you can.
To accomplish this you need to stand up against a wall/door with something that has a straight edge between your legs (barefoot).
Examples of things you can use as a straight edge could be:
A phonebook Carpenter’s square Piece of wood that is square
Once you have your straight edge against the wall and firmly placed in your crouch.
Have someone measure from the top of the straight edge to the floor.
Next you need to convert this measurement in to centimeters.
To convert inches into centimeters multiply the inches by 2.54.
The next step is to multiply your inseam in centimeters by .67.
For example if your inseam is 82 cm your equation would look like this .67 x 82 = 55. 55 is your frame size in centimeters.
Now that you have your appropriate frame size measurement. Let’s figure out more measurements to get the bike to really feeling comfy.
Our next measurement to calculate is our saddle/seat height. We calculate this measurement by multiplying .883 x inseam.
You use this number by measuring from the lowest point on the top of the saddle to the middle of the bottom bracket. The bottom bracket is where the front gears and pedals are located.
A way to insure proper saddle height is to extend your leg, on the pedals, and make sure there is a slight bend in your leg.
This is all the calculating you need to do to get correct sizing for road bikes.
To insure the ride is comfortable take a short ride around the block a couple of times.
If after you have taken your short ride and you feel “stretched out”. You might want to get a shorter stem (what holds your handle bars) or move your saddle forward.
If you move your saddle forward you might need to readjust the seat height to ensure proper leg extension.
If everything feels comfy to you, you are ready to go tear up some asphalt!
Next you need to convert this measurement in to centimeters. 
