Most ski bindings have installation jigs to allow you to coarsely set the distance between the binding toe and heel in increments of 10 mm. and then after installation, they offer you means to adjust the heel position (usually with teeth that click into a track) to be within plus or minus 2 mm. of the optimum position for the forward pressure, as typically displayed by a pointer landing on a scribed scale or in a window.
My binding is a demo type mounted on a racing ski that allows me to select the nearest 5 mm. of boot sole length by turning a single central key. Both toe and heel move at the same time as the key is turned in fixed increments of 5 mm.
Thus by taking any size boot, I can quickly size the binding so that my forward pressure pointer always lands somewhere on its scale.
My binding also has an additional (secret) adjustment which allows me to fine tune the heel position in order to force the same pointer to the middle of its scale. The manufacturer does not want me to play with this adjustment which is set in the factory so that all ski boot sizes will be accommodated without the need for any secondary adjustment.
Many people have argued that it does not matter where the pointer lands on the scale, as long as it does in fact land there. I don’t dispute this consensus. But after my heel prematurely released in a race, I began to think twice about this opinion.
The manufacture claims that by my fine manipulation of the heel position, I am tampering with the vertical release characteristics.
I agree with him but I merely contend that if the binding is designed to accept boots varying in length of plus or minus 2 mm. without compromising safety, then my displacement of the heel position by a millimeter or two should not compromise safety any more, as long as my pointer remains on the scale.
You may ask me what I would gain by trying to force the pointer to be on the dead center of the scale if the binding works so well over the full scale range.
My answer would simply be that if is true what the manufacturer says about there being no advantage to being exactly at the center of the scale, then why would he be concerned if I go to the trouble of actually forcing the pointer to the center of the scale in order to simulate a median boot size.
Either there is or there is not an optimum position on the forward tension scale of a typical ski binding heel.
Thanks for any feedback.....