We have all seen this guy pulling a bike like a rickshaw-puller, rocking his hips to reach the pedals even when his saddle is at its lowest. This happens when a rider ends up buying a much larger frame than his/her fit and consequently gets into an incorrect posture.
The position of the saddle should be ideally above the handle bar or at least level with it. This is possible only if the frame size is correct. A bigger frame will require the saddle to be pushed down and vice versa.
Two people of different heights cannot use one frame by adjusting the saddle, unless their in-seam length is the same.
The last column discussed how to choose the correct frame size by measuring stand-over height. There should be a minimum one inch space between your scrotum and the top tube when standing over a bicycle. Less than an inch, the bike is big for you and more than three inches, it’s small for you.
There are three critical measurements in saddle adjustment – height (image 1), fore/aft (image 2) and tilt (image 3).
Mount the bike on a trainer or ask someone to hold it straight for you. Saddle up, place your heels on pedals and bring one pedal close and perpendicular to the ground. In this position, this leg should be almost (not stretched) straight. Adjust the saddle accordingly.
This will ensure that when you pedal using the front of your feet, with your metatarsal bone aligned with the axel, you create an angle of 25 to 35 degree.