Finding the right saddle setback on road bikes

Fore-aft adjustment of the saddle is crucial, as it profoundly affects our comfort while riding and can impact the quality of our bike rides and the developing knee issues and back pain. Here are some tips for finding the most suitable saddle position for us.

Let’s start with the basics. Saddle setback refers to the positioning of the saddle along the longitudinal axis of the frame (forward-backward). Typically, saddle setback is defined as the distance between the perpendicular from the anatomical point of support of the ischial bones and the axis of the bottom bracket. Saddle setback or advancement (at constant height) has a significant influence on the knee because moving the saddle will also move the position of the patella relative to the pedal.

The acronym KOPS (Knee Over Pedal Spindle) defines the relationship between the pedal and knee positions. When the knee is vertically aligned with the pedal spindle, the load and muscular force on the knee are balanced. This position is best for avoiding joint-related issues.

There’s also a more “aggressive” position, where the patella is positioned further forward than the pedal spindle. This allows for more force to be applied but also puts more strain on the front of the joint, increasing the risk of inflammation. Additionally, shifting the center of gravity forward can lead to shoulder and arm fatigue, often resulting in tingling and numbness in the hands. Typically, this position is better suited for maintaining a high cadence and makes you shift towards the rear of the saddle during climbs. This is the preferred setback for track cyclists, whose efforts are particularly intense and concentrated in a short time.

The third scenario we consider is when the knee is positioned further back from the pedal spindle. This is the least efficient position, as it causes force dispersion, disrupts pedaling rhythm, and puts excessive stress on the back of the knee (popliteal fossa).

An empirical but still widely used method for finding neutral setback is too position the crank and pedal horizontally (at 3 o’clock) and check with a plumb line system that the back of the patella is aligned with the pedal spindle. Another method, less commonly used, calculates the vertical alignment not from the back of the patella but from its most prominent part.

Much more accurate measurements can be performed by a skilled bike fitter. Your bikefitter will consider various parameters, including frame measurements and geometries, seat tube angle, crank length, and your physical characteristics.

When transferring your setup from one bike to another or you just want to change your saddle, if your point of reference is the perpendicular from the anatomical center to the bike’s bottom bracket, the anatomical point is conventionally located where the saddle has a width between 70 and 72 mm.

We conclude this article with some advice. Very often we see saddles fixed to one end of the rail, generally to make up for a frame that is too short or long, or more simply because the seat post is curved backwards when, to adapt to your measurements, it should be straight (or vice versa, of course ). The travel of the rail must certainly be exploited to find the right setback, but it cannot be taken to the limit of the straight section to correct conformations of the frame or other components that are not suitable for you. In doing so, in fact, the sector of the saddle not supported by the clamp is subjected to excessive stress, especially when the weight of the body shifts to that side and during compressions due to unevenness in the ground.