Originally Posted by
PeteHski
Do you not find it a bit ironic that you are on the one hand defending "traditional" bike fit methods while attempting to re-invent how saddle set-back is defined? I don't think the way bike fitting has been evolving over the last few years is based on fads and fashion. It's more that the traditional methods were a bit dubious. KOPS being a great example as you rightly brought up yourself - although I'm not sure all 1970's European racers had the same body proportions. I'm pretty sure they were as diverse as in any other group.
Back on topic, I know of one fitter who is using a sddle setback method similar to what I think you are proposing. He found from client observation that in most cases setback correlated well with hip-marker alignment on a 73 deg line projected from the BB. If their hip marker was ahead of this line they would likely feel too far forward and vice-versa. This fitter was actually using KOPS as an arbitrary starting point and then the balance method to adjust. The resultant hip alignment with the 73 deg projection was an observation - which he now actually uses in his fits. He says it is largely independent of saddle height, although very tall riders tend to move forward of this virtual line.
I'm not trying to reinvent how set back is defined as much as find a more reliable method to place a rider in that traditional location using more reliable metrics.
And I think KOPS is less reliable because the white male population is less likely to be as diverse as the world population of both sexes. That hardly seems like a radical position to take. KOPS was never universal, but it probably works more often on the population it was extracted from.
Thank you for validating my hypothesis with an example of someone doing almost exactly what I described using the same angle number. Clearly I'm thinking along the right lines.