Author Topic: Re: New Approach to Binding Mount position; split from Stockli Laser SX review.  (Read 1807 times)

HighAngles

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Svend - thanks for the interest and here's more detail on the subject since Lynn has so nicely broken this out into its own topic. ;)

For years and years (long before we had factory mounting marks on skis and boots), skiers used the Ball of Foot (BoF) positioned on the Center of Running Surface (CRS, aka midpoint of the running length) when mounting their bindings.  Even after we got the factory mount mark on skis and the boot midsole mark, some skiers still preferred to go with BoF on CRS.  Of course this was before ski sidecut geometries and tip/tail profiles got, let's say, "interesting".  With dual sidecuts, early rise tips, and full-on rockered 5-point designs, BoF on CRS no longer produced the desired results (since determining CRS becomes quite problematic).  There has also been some confusion/controversy over how to properly determine where the BoF point really is on your foot and where that point is positioned inside the boot shell.  For the purpose of this post it's not necessary for me to get into the details of those issues.

So BoF over CRS evolved into BoF over CEE (Center of Effective Edge).  The Effective Edge length is the distance from the widest point of the tip to the widest point of the tail.  What makes CEE slightly tougher to determine is that it's the length "along" the edge, not the chord length between the two widest points.  IOW, you need to use a flexible tape measure to really do this right; to determine the midpoint between the widest points of the tip and tail.

Unfortunately even BoF over CEE fails with some of the more modern takes on ski design.  Some builders do some strange things with the positioning of the ski sidecut and also their new takes on ski rocker profiles.  That's where simplifying the whole process by just aligning the boot midsole mark over the narrowest point of the sidecut makes a lot of sense.  For this to really work well though, I would recommend that you have a fairly close fitting boot so that the midsole mark on the boot actually corresponds to the midsole point of your foot.

The best method I've found so far to determine the narrowest "point" on a ski's sidecut is to use a digital caliper.  Use the caliper to find the approximate narrowest point along the sidecut and then lock the caliper's measurement adjustment (usually there's a thumb screw to lock the jaws in place).  The narrowest waist measurement will sometimes occur over a "range" in the middle of the ski; possibly for 2cm or more. This can be handled by taking the locked calipers and marking the forward and rearward points where the locked calipers "catch" on the ski (slide the calipers through the narrow range and mark the forward and rearward points).  With those points marked, measure and find the midway point between them and mark that point as the narrowest point of the sidecut (basically it's the middle of the narrowest range of the waist found).  The main problem with this method is keeping the calipers square to the center line of the ski while taking the measurements.  I'm still working on a type of jig that can make this process faster and more accurate.
« Last Edit: January 01, 2013, 10:09:22 pm by HighAngles »