Twin Tip Cord Center?

Looking for tips to mount BD 01 tele binding on Fisher 96 T-Stix twin tip skis.
I know how to measure standard ski, but twin tip is new to me, especially tele.
I do not trust markings on the skis because of the potential for error in graphics. (would not happen on Kam and Kelvin's skis)
Any tips would help.
Thanks Joe

Joe:

this is a really good question.  Kelvin and i debated this last month in his garage.  i usually measure the length (both using the "as the crow flies" method or the actual length of the material of the base), then divide in half, and bingo -- cord center.  this is usually how i mount my bindings. (based on the fact that it's approximately the center of mass of the ski.)  i've also used the midpoint of the "running length", which is the length of the part of the base that contacts the snow when you stand on the ski.  (but this is a problem with the new "rockered" skis or some skis we have with reverse camber.)  i've even used the least squares method to fit a high-order polynominal function to the sidecut profile and then differentiated it, set the result equal to zero and solved for the horizontal distance from either the tip (or tail) to determine the bleah, bleah, bleah....    but in the end, for me the firsts two methods are "close enough for government work".  and what i've found is it's somewhat a mix of personal preference and science.   but significant fore and aft mounting does affect a ski's behavior. 

i think i've confused you more...

anyway, here's a link to some discussion at SB.  there are links within to TTips with more info:

www.skibuilders.com/phpBB2/viewtopic.php?t=671
www.skibuilders.com/phpBB2/viewtopic.php?t=591

Joe, I mounted my Fischer Atuas w/ boot center over boot center mark. On the Tstix the hexagonal patch on the center of the ski is were a decal would be for mounting zone. The center of that hexagon is the all mountain position for boot center. I mounted a HH on a Bomber second ski plate, I can use boot center over boot center mark or 2 cm back. I prefer bootcenter over mark. I found the markings to be very accurate and symmetrical on both skis. I love these skis, I want to get some O1's and skins for them.

I went around and around on this recently myself.
My setup was BD Verdicts 181 and O1 bindings with the midstiff cartridge. Previous skis/bindings included O2s with Mid Stiff and Volkl G4s as well as Head I85s with G3s. I tend to ski fairly aggressively for a tele guy, or so I am told.
My BD setup was by the book by the guys at Marmot. They skied like crap, nothing like the same set up I demo-ed in the spring... Big dives in the fresh soft snow. Made a couple powder days no fun at all :-[
I figured it was the mounting, I consulted a number of guys in town and measured til I was blue in the face. No consensus on the mounting. Then went Back to Marmot, BD had given them a book to go off of for the Verdict for tele mounts (in the event a ski tech somewhere was too stoned on P-tex to work a ruler I guess). The mount was spot on. Measuring by one method, which I think was 3 pin holes in the center of the ski, as measured from the tip and the mid tail (this is my term). Mid tail being the point half way between the actual tail of the ski and where the rise of the tail (where the p-tex leaves the snow, or work bench). It was the same as the book BD gave em.
Bottom line it was right, and it skied like crap.
So I talked with Craig at BD, he rocked. Turns out it was the cartridge in the binding causing my tip to dive. I went to a Free Flex and I love the binding. I swap out the cartridges for hard groomer days with the Mid stiff. I am about to play with the O3 heel throws. The issue is the geometry of the underfoot springs/cartridges. This binding has also improved my stance, causing turns to be more upright and powerful.
Good luck!

i've even used the least squares method to fit a high-order polynominal function to the sidecut profile and then differentiated it, set the result equal to zero and solved for the horizontal distance from either the tip (or tail) to determine the bleah, bleah, bleah....

...what the heck, should have not skipped class that day.

Thanks for the response Kam. Measurement is done. Cord center is 1cm behind the balance marking on the side of the ski.

On the Tstix the hexagonal patch on the center of the ski is were a decal would be for mounting zone. The center of that hexagon is the all mountain position for boot center.

Thanks Aaron-
I have read the O1 binding mounting instructions and they seem to be way off base compared to your plan Aaron.
O1 binding instructions has the pin line right on mid cord. That looks to far back.
So, I looked at your proposal:
Figuring my 1/2 boot length measured from the dot in the center of the hexagon, that put the pin line 7.5cm in front of the measured mid cord.
But, that looked more realistic as far as placement on the board and flexing the board looks to hit the sweet spot better.

Can't help thinking, why are Black Diamond's instructions so far off the mark for this ski?

Any other's support this information?

I went around and around on this recently myself.

Thanks JD-
Great info to keep in mind.
Joe

I think mounting tele bindings so that the boot center is over the mark on alpine skis probably is the most reliable way to get the sweet spot. I've done this on three pairs of skis now and am happy with all the results. I think tele specific skis should come with a boot center mark. Pins on chord center, ball of foot/center running surface/balance point and other methods for mounting tele bindings are cumbersome and unreliable. Manufacturers have the ability to find the sweet spot of the ski better than we do. I also believe there is no difference for the sweet spot between alpine or tele.