First of all, and this is THE most important tip, always mount according to manufacturer’s recommendation first. They designed the ski, they know its construction, you should trust their expertise. Whatever they recommend, no matter how silly it sounds to you and your 50 years of knowledge, try it first. If you bought a nordic or XCD ski, chances are there will be some markings on the skis. If there are no clues on how to mount, contact the manufacturer or visit their website and follow their advice. All the following methods and rules are pointless if you were already given a proper way to mount your skis.
Second, please do not follow what I say. And do not trust your local ski shop either. Make your own opinion. Experiment. We're all different, with different bodies, different skills, different techniques and different goals. I will not get into details here, because there are as many different opinions as there are telemark skiers. But let’s take a quick look at the most common ways to properly mount tele bindings.
The boot center method can be quite confusing. Because there are some many types of boots, with totally different flex patterns. And there is no standard way for measuring Boot Sole Length (BSL) with tele boots. Some people will measure BSL and divide by two to get boot center. Some others will remove a few centimeters to compensate for the duckbill length. Some will measure from NNN bar instead etc. I prefer to use this method only for NTN, and using Pins on Chord Center for 75mm heavy telemark.
If you want to turn your old alpine skis into a tele setup, don’t forget to mark center line BEFORE removing the alpine bindings (Measuring the distance between heel and toe pieces)… You might not find any BAL marks on the ski.
What if there is no mark and no information available?
This is very common. Mounting tele bindings can be so confusing that sometimes even current ski makers won’t even put any kind of marking on their new skis. Even if the company provides a very clear way to mount their skis, here is what I always do before I drill a pair of skis.
The more advanced, yogic way of mounting telemark bindings
When I get a new pair of skis, I always check for the manufacturer’s recommendation. This is always my #1 choice. But I also lay down the ski on the bench, and take all the measurements I can.
I start by finding Balance Point and mark it down on the ski with a sharpie. Then I also mark Chord Center and CRS. I also check cosmetics and sidewall for any kind of center marks. If the ski is to be used with plastic boots, I check boot center and where the corresponding pin line would be. And then, using a caliper or compass on the metal edges, I also mark the narrowest point of the ski, the sidecut’s center. This is where pressure should be for perfect arcs. So now I’m left with a ski with several markings on it. Most of the time, they all will be within the same range, around the same spot. But sometimes not. And now, finally, I put my boots on and stand on the skis. And this is where I let magic and feelings do their job. I place my feet on every mark on the ski and try to visualize how it would ski. I move the skis, flex my knees and imagine going down under different terrain and conditions. It sounds silly, but it works. Sometimes the manufacturer’s point may look weird, but once on the ski with your boots, you can instantly feel if something is right or wrong.
Do not try this magical Perfect-Binding-Mounting-Position-Visualization ™ technique if this is your first pairs of telemark skis. After mounting several pairs of different kinds of skis and skiing them a lot, you get an idea of how they will react. But you have to handle them with your bare hands, flex them, squeeze them, analyze them, FEEL them. There are so many variants and so many different ski construction combinations, they will all react differently with different mounting points. And always keep in mind what you intend to do with the ski you are mounting, where you will ski and what kind of boots you will use.
Most of the time, I end up pretty much around CC for XCD skis and around boot center -3 for NTN. And that is the real beauty of Rottefella’s Freeride binding, the option to move the binding around +/- 1.5cm aft and fore without re-drilling.
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 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.
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 / Binding 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.