Anthropometric relationships of the majority of the Western population Crotch / Height = 0.47 Trunk / Crotch = 0.76 Arm / Crotch = 0.87 
CALCULATION
OF BICYCLE FRAME
The type of calculation depends on the structure of the frame. Who is interested in the calculation of the structure as traditional sketch number 1 below calculates in this page.
Who is interested in the calculation of the structure with inclined horizontal pipe as per sketch No. 2 click here and you move to another page because the process is different. (Slope Frame)
On the left are represented measurements of the Cyclist. The key measure for the dimensioning of the bike with traditional frame as shown in Figure 1 is represented by the length of the Crotch.
The height of the Cyclist, the length of the trunk and arms do not enter into the calculation but may serve in the Cyclist to complete a selfassessment of its body proportions if it considers that they are different from the majority of the population. Click
here if you think your body structure has significant disproportions. Measuring only the length of the Crotch, the Cyclist with normal body proportions is able to calculate the frame of the bicycle racing or sports and mountain biking, as specified below if you belong to the type Image 1 above. Why the height of the cyclist does not enter the calculation? Because the height avoids upset their calculations for those Cyclists who have a long or short neck or head developed vertically rather then horizontal. The length of the head and neck have no role in determining the size of the frame that is right not to consider them. The proposed method of calculation is taken from the book: 'Road Racing: Technique and Training Bernard Hinault and Claude Genzling (Authors)' and will be fully implemented in all traditional bikes: Road Bike, City Bike and Mountain bike as figure 1 above. For bikes with inclined tube horizontal (SLOPE COMPACT), not present in the 90's when this method has been widespread, it need to follow a different procedure. Click here. Click here to learn how to measure the length of the Crotch When the cyclist knows the extent of his Crotch can calculate the frame of any type of bicycle having frame as the image number 1 choosing from the following paths:

The main measure that characterizes the bicycle frame is the height H ( capital H in the sketch below), other dimensions are proportionate to it in the bikes that are on the market since they are related to the anthropometric misures of the Westpopulation.
Click here if you feel that your body structure has some significant disproportions.

H = height of the frame measured between the axis of the pedal and the midair intersection of the tubes. Click here to find out how to take the measurement.
Hs = Seat height: distance between the axis of the pedal from the notch of the saddle, on its top. Click here to find out how to take the measurement.
R = Receding of the saddle: the distance separating the tip of the saddle from the vertical axis of the pedal. Click here to find out how to take the measurement. S = Distance saddle handlebar measured from the tip of the saddle and the center line of the horizontal part of the handlebar. Click here to find out how to take the measurement.
D = gradient saddleattack: measured between the top of the saddle and the top of the attack of the handlebar. Click here to find out how to take the measurement.

Formula for determining the height H of the bicycle frame (SEAT TUBE)


Rice BikeH=0,65 x C

C is the measurement in Centimeters of the Crotch.Multiply the size of the Crotch in centimeters for the fixed number 0.65 to have the height H of the bike race.


Road / Trekking Bike *H=0,66 x C 
C is the measurement in Centimeter of the Crotch.Multiply the size of the Crotch in centimeters for the fixed number 0.66 to have the height H of the Road / Trekking bike.
* Note: The frame of the Road/Trekking bike is structurally the same as the race bike, took the name as a function of the addons that the native racing bike does not have as wings, cover and diversity of the handlebar. The fixed number of the formula is slightly higher (0.66 instead of 0.65 Road Bike) to take into account that the posture of the Cyclist is not competition but purely theoretical question of a difference that does not stop, if desired, to eliminate mentioned components added, changing the handlebars and tires to turn sports bike racing bike. Each racing bike can be transformed into road /Trekking bike bike and vice versa. 

Mountain Bike (MTB)H=0,58 x C 
C is the measurement in Centimeter of the Crotch.Multiply the size of the Crotch in centimeters for the fixed number 0.58 to have the height H of the bike race.

After determining the size of the frame should adjust the seat height Hs (See sketch bike on a dark background above)
The seat height Hs is determined by the following calculation:


Hs=0,88 x C 

The
formula is the same for a rice race  City Bike  MTB bike but not for
bike walking where the seat is adjusted depending on the support of the
rider's feet on the ground. With the above specifications, the calculation described above is applicable to all types of bikes.
Click here for checkup of your ride style

Setback of the saddle  saddle handlebar Distance  Standard seatattack
Table Value of R S D This table shows the ranges of adjustment of the parameters that characterize the overall structure of the Cyclist on the bicycle related to various ranges of the measure of the 'Horse'. (See figure above) 
Note on the handlebars In the above image is represented a road bar as the studies described in this page refer to this type of handlebars but it is worth pointing out that the distance S, as measured from the tip of the saddle and the horizontal straight handlebar, allows extend the values suggested in the table on the right to the right handlebar of Moutain Bike and to the to the right handlebar mounted on a racing bike, trakking bike, city bikes, hybrid bike.


C (Cavallo) [Cm]

R [Cm]

S [Cm]

D [Cm] 

75 78

46

4751

56 

79 82

57

5054

67 

8386

68

5357

78 

8790

79

5660

89 
Criteria of Regulation of Handlebar and Saddle
The adjustment of the parameters S and D determine the distance Seat  Handlebar and are determined according to the primary objective cyclist or its compromise between: Speed Search  Comfort of movement  path (Plain, Mountain, City, Mixed). The setting of the parameter R refers to the style of riding that is a factor inherent in each Cyclist, only partially malleable by the will and training. The majority of the Cyclist pedaling with the saddle forward by dropping the power from the pedals. A minority pedaling from behind. (This second mode, in the opinion of Bernard Hinault, is the best but few Cyclists are able to implement it. See the note at the bottom to find out why.) The above means that every Cyclist has for himself, the best combination of these parameters that must be determined by testing and recording the results.What is good for a Cyclist, as regards the adjustment of R, S and D might not work for another yclist, even with the same Crotch and body structure. The following are the criteria for adjustment in some typical situations. 1) The overriding objective of the Cyclist is the pursuit of speed. He will have to minimize the effects of air friction assuming a position as possible aerodynamic and therefore must lower to the maximum the handlebar so as to be convenient when the search speed with hands resting on the lower part of the handlebar by acting on the S parameter while the parameter D should be directed to the maximum in order to better cut the wind. The adjustment of the parameter R, as already said, depends on the style for which, the cyclist that decreases from the force on the pedals will adjust the value to an intermediate position between those sugerite in the table while the cyclist pushing from behind can retract the saddle the maximum value of the range.
2) Cycling uphill The values S and D in the mountains made uphill, due to the modest effects of air friction, due to the low speed, assume less importance and may be reported to the intermediate values of the table for any style of riding. The parameter R instead, will take account of the different styles that the cyclist that decreases the strength from all you need to be adjusted to the lowest value Seat full forward) since, by that ride the cyclist must ride with your torso leaning forward to balance the change of center of gravity caused by the bike inclined upwards. The few who are riding Cyclists from behind, however, can continue to maintain this position of the seat back
3) The Cyclist does not have the speed as primary goal because it seeks a compromise with the comfort and safety of having to ride in urban traffic or for relaxing strolls without obligation. Adjust the parameters R, D, S values lower end of the range suggested in the table for his measure of the Crotch and this will allow him to ride with the torso more upright than the competitive positions of the above cases, you can see better what is happening around since the neck is more erect but exceeded the speed of 15 km / hour air resistance that will have to win will begin to be felt more so, with the same speed of the previous adjustments, will make more effort. Note: the position of the seat The question haunts many Cyclists, this is the opinion of Bernard Hinault. ...... The ergonomics teaches that it is more efficient pedaling from behind with a backward movement of the saddle relevant, rather than forward, when it comes to road cycling for two main reasons: 1) E 'easier in this posture push the foot forward in the passage from the upper dead point, and pull it back in the lower dead point, and this produces a greater regularity of pedaling, with the increase of the continuity of the transmitted force on the pedal. 2) The thrust of the foot tends to stabilize the pelvis on the saddle which further contributes to the regularity of pedaling. The legs can be dedicated solely to power without intervening, by extension, against the instinctive tendency to move towards the tip of the saddle when the effort is very intense. Over the seat is forward, the more the cyclist slips on the saddle, because of a downward displacement of the point of application of pedaling power. It 'difficult for many to adopt its position due to lack of elasticià and strength at the lumbar spine. With a gym apppropriata lengthening the chain of moscoli back and hamstrings, especially if you practice from an early age it is possible to approach the 'ride from behind' ......
