Originally Posted by
Wesley36
I would say that you are setting up a false opposition here. Choice of saddle should be informed BOTH by pelvic rotation and the distance between the sitz bones. If one was to oppose them, knowing pelvic rotation and not sitz bone distance is more useless than knowing sitz bone distance but not pelvic rotation. Ass-o-meters do what they are supposed to do, but it is a case of garbage in - garbage out. Why, for f's sake, would one sit armchair fashion on an ass-0-meter? You are right, it is a quick way to get a meaningless number, but that is not the fault of the ass-o-meter.
If it is going to be a meaningful exercise, one needs to adopt a position similar to the one on the bike when sitting on the ass-o-meter, for the reasons you have outlined. This does not mean discarding ass-o-meters, it means using ass-o-meters properly and interpreting the information correctly.
not sure what you mean by false opposition. Did you mean false premise or supposition?
Good point about how to sit on an Ass-O-meter. Btw, have you done this? When sitting in a forward rotated position on a Ass-O-meter do you really get 2 distinct points? I would like some proof of that. Seems to me the inferior ramus where one really sits on a road bike saddle is in effect, two converging boney rails or protrusions. I am quite sure they would not leave a clear demarcation of sit bone spacing when sitting in a proper pelvis forward rotated position.
Therein leads to the further myth about correlating an Ass-O-meter measurement to actual saddle width. How much side to side distance should one leave to each respective edge of the saddle to each touch down of the pelvis to the saddle. 5mm? 10mm? This isn't quantifiable with any sort of science.