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I’m a little confused on the 26m-radius spec for the K2 Apache Chief. If I plug the numbers into Physics Man’s calculator (thanks PM) I come up with a radius of 42.3 meters – not the 26 meters that is printed on the ski.:

Using the same calculator for the 190cm Explosiv I come up with 33.6 meters, which is certainly close enough to the 34.6-meter spec.

What am I missing here? Why the 16 meter discrepancy?

Also, anybody notice that the 8mm sidecut of the Apache Chief is in fact the old sidecut from the “K2 8.0” straight slalom skis of yesteryear?
Just to confuse the issue a bit more...
My 174cm Chief also states 8mm sidecut, but the K2 website states 12mm which seems to correlate with the 126/98/116 dimensions. The website also states 23m radius on the 174mm ski.
Quote:
 Originally Posted by Woodee I’m a little confused on the 26m-radius spec for the K2 Apache Chief. If I plug the numbers into Physics Man’s calculator (thanks PM) I come up with a radius of 42.3 meters – not the 26 meters that is printed on the ski.: Using the same calculator for the 190cm Explosiv I come up with 33.6 meters, which is certainly close enough to the 34.6-meter spec. What am I missing here? Why the 16 meter discrepancy?
I'm not sure exactly what the problem is, but I will say that before I posted it, I checked my spreadsheet by comparing its results to the sidecut radii of a few dozen skis for which I had published radius data, and all the calculated radii came out in a range of about plus or minus 5% of the published numbers.

One known limitiation is that my spreadsheet assumes that the ski is not a twin tip. If the ski you are interested in is a TT, you've got to reduce the effective length of the edge even more compared to a non-TT. In short lengths this can seriously reduce the calculated radius, but a reduction of 16 meters is much more than I would expect.

At this point, I would suspect something simple like a typo somewhere. As a starter, why don't you take a ruler to the ski and double check both sidecut and effective contact length dimensions. Let me know what you find.

Tom / PM

PS - You could also put an Explosiv and a Chief base to base, slide them fore-aft and side-to-side so that the waists on one edge of each occur at exactly the same place, and eyeball the sidecuts. Does the Chief look like it has a larger or smaller radius?
K2 Apache Chief, 126 - 98 - 116 (that seems to be the advertised dimensions) = 11.5 mm sidecut, not 8.

In a 174 cm length, I get a sidecut radius of 25.5 meters. That's using (I think) the same method as Physicsman, though I might be using a slightly different method to estimate effective length from full length. I'm knocking 12% off the full length ... when I compared a bunch of claimed radii to calculated, that made the two closest. Of course, you'd need to measure every ski individually to be really accurate.
Follow-up:
I sent K2 an email and evidently some of the Chiefs have misprinted badges which state 8mm sidecut. K2 states that the sidecut is 12mm as stated on their website.
I have tried using this formula as well, and I have also come up with results that have been highly suspect. I believe the error to be in the effictive length. This is because the tip and tail measurements (widest points of the ski), might be beyond the contact point of the ski. As is the case in in most Volkl skis, which use what they call extended tip profile.
Quote:
 Originally Posted by sjjohnston K2 Apache Chief, 126 - 98 - 116 (that seems to be the advertised dimensions) ...
Hmmm ... mine are 181cm and the little plaque states 118/98/108.

However, after measuring them they are in fact ~126/98/116.

: Chinese math ?
Woodee, do you suppose those mis-prints are part of the reason for the huge discount? (Sitll waiting for on-snow review of these...how about it Utah49?)
If the reason I got the ski for \$299 is because of a misprinted badge then I'm still sleeping very well at night.
I am looking at boards currently, aside from these strange discrepencies how do they ski? Because thats what really counts. 299 is an insane price for a 2005 ski. What formula do you use to measure the radius btw...

Alfonse
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