All this was largely an artifact of italian designs and several archaic seat height methodologies some based on the coni. The most important body measurements for determining the correct bicycle frame size are your height and your inseam.

Bike Fitting Vs Bike Sizing Two Pivotal Aspects Of Cycling
Body measurement for bicycle. Database of bike measurements that may or may not have fit. We need 8 core pieces of information in order to calculate your optimum frame size and initial position. While these two numbers alone will not guarantee that a bike is a perfect fit by using them and a sizing chart you can eliminate bikes that clearly are too tall or too short for you. Mountain bike leg inseam cm x 066 your frame size road bike leg inseam cm x 070 your frame size if your leg inseam is 76cm then your right mountain bike size is 50 cm 20 road bike 53cm and city bike 52cm. Ideally youll know your bike size before you buy. Listen to your body.
You can easily measure this by standing with your back to a wall and making a mark level with the top of your head. Find the best bike size for you. Firstly you need to know your full height. For mountain bikes take the same measurement and multiply 06 you will then need to change the centimeters into inches. Itll make the whole process easier and youll be set up for success right from the beginning. Measure the distance from the mark to the floor and thats your height.
The bike body contact points are. Yes no two people have the same body measurements. Bike fitting is the process of fine tuning the position of the bike body contact points in relation to each other for your riding comfort efficiency and performance. If you want to know the sums then to find your road bike frame size take your inseam length in centimeters and multiply it by 070. Finding the correct frame size is key to your safety and enjoyment our guide walks you through everything you need to know in order to measure a bike frame. For a hybrid bike take your inseam and multiply it by 069.
Feet to pedal butt to saddle hand to bars a bike the wrong size or shape does not allow for an optimal fit position to be established. The way to measure and record reach is from your seatpost right under the saddle to your headset and if you already have a great fitting bike noting its top tube length for future bike. To calculate your correct bike size you have to know a couple of body measurements.