Subject: RE: Brooks Pure Project? How is drop figured? When I review a shoe I measure the thickness of the sole from inside the shoe on the heel bed to the outsole. Then, I remove the laces, pull back the tongue and use the calipers to measure the forefoot thickness from the middle of sole parallel to where the metatarsil sits. Subtract the smaller (forefoot) number from the larger (heel) number and there is your unloaded drop. But be careful: Different midsole materials compress at different rates depending on their durometer. A full EVA midsole will compress at about the same rate heel to toe, but add in denser foam at the heel and the rate of effective compression on foot strike changes completely. That changes the geometry of the shoe. A shoe doesn't "run" how it looks sitting onthe shelf. The dimensions and geometry of the shoe change dramatically as the foot strikes the ground, exerting a number of "G"'s of impact force and deforming the sole. For that reason the wisdom of comparing shoe drp geometries has to be tempered against an understanding of the materials used in the midsole and their real-world compression under load. Look at the change in the sole of this shoe I photographed a few weeks ago through a gait cycle: |