Saddle Fit: Make Friends With Your Ischial Tuberosities
Critical in any proper bike fitting and saddle adjustment is the actual width of your sit bones, and the pressure created by the two points of bone that you feel when you sit on something flat and hard. These points, or “ischial tuberosities” (try using that term at a cocktail party to impress someone), must be supported by your seat properly if you are to be comfortable on your bike. If your bicycle saddle fits too narrowly, the soft space between the bones must hold your weight instead-resulting in numbness and discomfort. If your bike saddle is overly wide, you will experience thigh chafing, especially if the pedal cadence is set higher. So, how do you figure out what a good starting point is for saddle width for you personally? Start out by finding what your ischial tuberosities need and then look at overall pressure distribution. How?
A few years ago Specialized came out with a foam tool designed to quickly measure sit-bone width in-store with the thought that this would help the rider select an appropriate width saddle. Good ideas in premise don’t always work as well in practice though and our experience is that the “Body Geometry Saddle Fit System” does not always tell the full story and may actually be misleading in some cases – putting the rider on a saddle that is too narrow or too wide in practice. Why is the BG Saddle Fit System used then? Well, many shops use it because it is cheap and simple, makes sense on paper and the industry hasn’t really had anything much better outside of the experienced analysis/information some of the best fitters could provide – which was still limited when it came to actually being able to fully understand what a rider was experiencing and what would mitigate it best. The downfall to the BG Saddle Fit System is likely that it locates the width of the ischial tuberosities in general, but it doesn’t show the shape of the sit bones or how they interact with the saddles being considered. While more involved and not readily available, a saddle pressure scan with a qualified technician does all of this.
Fit Werx now offers full gebioMized powered saddle pressure scans at all locations. We include an initial scan in our standard Existing and New Bike Fittings and independent pressure analysis sessions for chronic sufferers who have been properly fit before, but are still having saddle problems, are also available.
