Originally Posted by Kontact

This would be true if cyclists actually sat on their "sit bones"; the Ischial Tuberosity. We sit on those in chairs, but most people on bikes are leaned forward and are sitting on the narrower Iscial Ramus.

Specialized has come up with a system that suggests saddles based on Ischial Tuberosity width, but that doesn't mean that's what you're sitting on, it just means that the Tuberosities are easy to measure and the Ramus is not.

Also, the outer width of a saddle doesn't really predict how wide the part you sit on is going to be. It depends how the saddle is curved and whether it drops off quickly or not.


Kontact makes a phenomenally ergonomic saddle, and many people riding them have sit bones that are wider than the saddle itself. But no saddle works for everyone. So I would suggest sticking to trial and error rather than arcane measuring formulas. Just note what kind of shapes work and what don't.