Chord Center mounting- does it make any sense?

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teleclub

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Re: Chord Center mounting- does it make any sense?

Postby teleclub » Mon Jan 15, 2018 4:08 pm

For me, the important thing to know about chord center is that it was the old alpine standard mount point back before ski manufacturers started to put boot center marks on skis (or when it was still rare).

Back then, any ski mount required just one question: is it a nordic ski or an alpine ski? If the answer was nordic, then balance point. If alpine then chord center.

This is how people thought even into the early 90s. Nordic tele in its early stages was ignored by everyone. The only confusion was how to measure chord center and ski-geeks like us would only argue about whether the tape is held taut or it it's supposed to follow the ski curve, etc. Old ski books had chord center diagrams and measuring explanations but gear freaks like to have an issue to discuss.

Balance point is obvious for nordic because classic striding means you pick up the ski by the pin-line and you don't want the tails to drag--you want the ski to be as balanced as possible as you pick it up. A chord center mounted nordic ski will be heavier in back and will drag a bit when you lifted that ski with your foot/toe. (Since as Phoenix and LC point out, CC almost always meant a mount point more forward than BP.)

Then two confusions arose. The small one was the appearance of boot center marks. SkiMechs working in alpine shops didn't miss a beat and just mounted according to boot center, if there was a mark. Since tele skiers back then at least, were inveterate home mechanics and do-it-yourselfers (dirtbags), you heard questions which I thought goofy: "should I put pins on balance point, pins on chord center, or pins on boot center?" Doh! "Boot center" means the center of the boot not the toe or the pin line... IIRC, some skis came with a marked boot toe line, which added more confusion.

The bigger confusion that arose is the one that's so familiar to members here on this forum. It's that early tele had two goals that came into conflict when it comes to mounting point. Some thought of telemark as a useful skill for turning your XC skis on tour, so of course you would use balance point since your goal was efficient touring. In other words the turn served the tour.

Others thought of telemark tun as an end in itself, and touring was for getting you into the backcountry to the good slopes; the tour served the turn. So of course you'd use chord center since the point is to maximize turning ability.

(Here at TTalk we might call this XCD vs. telemark and this site fully appreciates both I think. I valued both back then and never wanted to be forced to choose, so the fact that most here seem to value both is part of what makes TTalk (and to lesser extent TTips and Telemarque before it) a good place find balance and find both--XCD and Telemark.)

In the early 90s when there were multiplying options for turn-oriented skinny single camber teleskis, this always came up with my friends--Question: "you going to use balance point or chord center on them new Kazamas/Tuas/BDs?" Answer: "Chord center, duh! It's not like they're Karhu touring skis or Rossi Randos." This conversation could also be heard on the chairlift, which shows how mixed the goals were.

Around this time, it became increasingly common for tele skiers to use alpine skis so the boot center mark confusion mixed into it more and more. Top sheet technology got better so you'd see detailed boot center graphics on a ski instead of a discreet engraved line on the side wall.

As we said on the other thread, early rise and rocker adds a lot of new variables, and even for alpine skis has scuppered the old simple turning ski rule: "chord center unless there's a boot center mark".

But I think there is still a simple way to figure this all out. First and most important is "how was the ski designed?" Ski design is complex now. In LC's mount question on the other thread, he did the right thing--asked Asnes and went the extra mile to assure himself he wasn't getting an old school pat answer from a nordic traditionalist, but that balance point was in fact the carefully designed recommendation. Odd in a way for a ski designed for turning, but if that's what Asnes says then that's what it is. "How was the ski designed?" can be usually be answered from marketing language and instructions on the top sheet, but asking the designer directly is helpful. This is why chord center may be obsolete now in that it used to be the way all turning-oriented skis were designed and now ski designers seem to use it rarely. I'm still curious about cc and will measure it, but I won't use it for mount point unless it's an old ski designed that way.

Second question to ask: "Is my intended use of this ski consistent with how the ski was designed?" This used to be more important back in the day when telemark meant using XC and alpine skis in ways they weren't intended. Today it's still possible that it makes a difference, say if you are mounting up a hardpack ski to use mainly in deep BC powder you might mount further back a bit. Or if you're mounting a BC ski for hard charging on hardpack you might mount forward a bit.

Third: be prepared to experiment. Alpine skier forum talk is full of this same question nowadays, trying to figure out whether a centimeter or two forward or back might be a better mount point. They seem to treat the manufacturer recommendation as just a suggested start point. I think it's no coincidence that so many alpine binding are adjustable fore and aft for skiers to experiment and fine tune. Experimenting includes listening and I learn something from the experiments you all make and report back on XCD and telemark skis. Altai's forward mounting recommendations was mentioned and that seems to be the result of experiment and trying it multiple ways. On their site they describe how they decided mount point by trying variations extensively in snow. This makes me interested in a plate like the B&D or the NTN Freeride plate that allows mount point adjustment. For any future XCD oriented 3pin binding mounts I plan to use quiver killers / Bindig Freedom inserts so that if I want to experiment I can put in three more ahead or behind. When I was mounting up a La Sportiva Lo5 last year, I read up on the ski, and found that the designers and testers had changed their mount recommendations, moving it forward 2-3cm after skiing it for a season on a two continents and comparing notes. A guy from the Lo5 design team had joined the review comments, in a Blister review I think, to tell the story and he gave the recommended distance from tail to boot center for each length of the ski. Finding the archived review comments allowed me to measure mine to see if the boot center mark was the corrected distance or not. If my new old stock Lo5s had had the old mark, I would have mounted an inch behind the best recommendation. To me, the new ski designs means it pays to do this kind of searching out info.

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lilcliffy

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Re: Chord Center mounting- does it make any sense?

Postby lilcliffy » Mon Jan 15, 2018 8:44 pm

Teleclub- your post was a work of art man. Greatly appreciate this.
The pursuit of XCD balance: cross-country AND down-hill skiing in the backcountry

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t-$

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Re: Chord Center mounting- does it make any sense?

Postby t-$ » Mon Jan 15, 2018 9:47 pm

wow, thanks for that historical perspective on this. that was very interesting and informative. in reply, another xcd ski mounted bars on bp today. i'll let you know how they ski when i ski em, but it seems us xc guys don't need to overcomplicate it and just go with the bp! thanks guys...

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fisheater

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Re: Chord Center mounting- does it make any sense?

Postby fisheater » Mon Jan 15, 2018 10:38 pm

Great posts, it is funny that I can agree that I believe a cm or two should be something that most skiers will adapt to. On the other side of the coin, I believe that new rocker designed skis are changing the rules. When I first flexed my new FT 62 skis, I was very concerned. I thought they would require a mounting position rearward of balance point. I emailed Asnes and they said balance point.
I was quite surprised that balance point was what seemed rearward to me, but in realty was chord center, and 2 mm in front of chord center on the other ski.
The point I am making is that rocker does change how we mount skis. From the start Asnes recommendation of BP was important to me, but it when their recommendation confirmed my initial thoughts on where the ski needed to be mounted, that was reassuring. While telemark skiers tend to be independent free thinkers, I believe we will need to rely on the ski designers. As for chord center, when I started mounting alpine skis there was a boot center mark on the sidewall. The only pins I have mounted are at BP. I don't believe there are designers designing skis around a chord center position for pins. On the other hand, chord center would have given me the same results on my recent mount.

teleclub

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Re: Chord Center mounting- does it make any sense?

Postby teleclub » Tue Jan 16, 2018 1:39 am

lilcliffy wrote:Teleclub- your post was a work of art man. Greatly appreciate this.

Thanks, my pleasure.
fish eater wrote:...I was quite surprised that balance point was what seemed rearward to me, but in realty was chord center, and 2 mm in front of chord center on the other ski.
The point I am making is that rocker does change how we mount skis. ...

Agreed and I continue to think it's impressive that Asnes can design their skis to end up this way. They had to plan it so the exact same amount of weight was behind that point as in front of it. That's the definition of balance point of course, but to build the ski so the bp mount position matches up with the other mount positions options must take some planning. Shows Asnes's nordic reluctance to compromise touring balance for the best turn initiation method--let's just make those the same. Very cool.


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