Originally Posted by
Scooper
The ass-o-meter patent shows the need to elevate your feet to make an angle between your upright trunk and your upper leg roughly simulating your seating position on the saddle (~30° - 45° for aero, ~40° - 75° for more upright). Your sitbone distance will vary depending on the angle as shown on the patent drawing. And, yes, you get two small, distinct impressions from the sitbones; the distance between them is easily measured.
Thank you for this. Here is why:
Two or three years ago, the max saddle width Specialized made was a 155, as directed by the Ass-O-matic. Today, they make saddles up to 168. Did sit bones expand exponentially (or linearally at not a non-linear rate) to warrant new models in 168? My old reading led to a 143, and it worked perfectly. I bought a Selle Italia in 143, and it feels slightly narrower, but not uncomfortable. However, I would today be steered to a 155.
And the guy I worked with to get my first Romin, with the Ass-o-matic, was brilliant, or an extraordinarily accurate liar. He looked at my measurement, looked at my bike setup, and told me I was between sizes, and recommended the 143. He also specifically said (and I remember it because it proved to be accurate) that if I was intending to maintain or increase the amount of saddle to bar drop I had, I would love the Romin 143. If I intended to relax it, I should go to a Toupe or a Romin 155 (when 155's were 155's and not 168's). I loved the saddle, but hated it when I went to a less aggressive set up for a short duration.