Is My Saddle Setback Correct?
How do you correctly set the fore/aft position of your saddle? The most common mistake people make is to adjust the saddle position to alter the reach to the handlebars. We need to set the saddle position relative to the bottom bracket and pedals, based on your individual characteristics, then adjust the handlebars to suit the saddle position. Before looking at the saddle setback you need to get the saddle height and angle correct (see previous posts). If your saddle is too high then it may appear too far back and if it is too low then it may appear too far forward.
With the saddle height correct and the cranks horizontal a plum line from the bony lump just below your knee cap should intersect the pedal axle or be slightly behind it (this changes for a TT/Triathlon position, we will come back to that later).
This is challenging to do as you also need to hold your foot in approximately the position it will be in when you are pedalling. Taking a short video and putting a line on it with the cranks horizontal works much better. If you adjust the fore aft position then you need to recheck the saddle height as moving the saddle forward or back will alter the height relative to the pedals.
Even if your saddle height is correct, having it too far forward can cause pain at the front of your knee due to the forces created by your knee being too flexed. If you have your saddle height and set back correct and are still suffering knee problems then you may need to look at crank length, especially if you have short legs and long cranks.