Adjustment 1. Seat height
Using a tape measure, measure the inside seam length whilst standing with no shoes on. This figure is then multiplied by .88. For example, an inside seam length of 67 cm x .88 = 58.96.
Therefore the height of the seat, measured from the centre of the crank to the top of the seat will be 58.96 or 59cm
Adjustment 2. Seat tilt
Ideally the seat should sit flat/horizontal as increased downward slope causes riders to slip off the seat.
Adjustment 3. Seat fore/aft position
This is how far forward or back the seat sits. Sitting on the bike with pedals in a neutral position (horizontal or parallel to each other), a plum bolt is dropped from just behind the little bump on the leg just below the knee cap (this bump is called the tibial tuberosity) and should land inline with or behind the pedal axis. If you don’t have a plum bolt you can use a retractable measuring tape.
Adjustment 4. Cleat position
For those riders who wear cleat shoes this is very important, but is also specific to the individual. As a rule of thumb the base of your big toe should sit directly over the pedal axis.