We clearly have a need for new technology. First we have a chip/emitter implanted on the pivot of our hips Then another we can locate at the ball of our foot. Then a readout of the total and horizontal distances between. (Better do both hips so no cheating.) Then when we get a bike right, we note the distance. Now it is child's play to set up the next bike. Seat, shoe and cleats are all automatically accounted for. For now, we probably have to use local emitters and receivers, but in 5 years or so we ought to have GPS down to the required accuracy.

In all seriousness, this is what we are striving for: to locate the hips properly about the crank circle. A set number doesn't work when seats change, different shoes/cleats/pedals are used or clothing alters our position. I go by knee bend at the bottom of my pedal stroke. With traditional pedals (and this works fairly well with my other pedals) I sit on the bike barefoot and place my heel on the pedal.. For me, the ideal seat height is when I can either bend my knee or straighten it without rocking my hips. I like my seats lower than many people. It you want higher, wear a slipper or cycling shoe with no heel. Higher still? Try a shoe with a low heel. This approach takes different seats completely out of the equation. When you find a bike/seat that is right, do this test, looking for the shoe/sock combo that hits that spot. Now you can quickly get any seat on any bike to close to perfect. All that is left is compensating for different shoe/cleat/pedals.

Ben