Backcountry Skiing Binding Conundrums
After our discovery that the Fritschi Explore front screw layout is slightly different than that of the Freeride, a person questioned the distance between front and rear binding units as shown on our paper template. To get the final word on this I visited Summit Canyon Mountaineering in Glenwood Springs, Colorado, measured their factory binding jig and spoke with their shop tech.
First, I verified that shops can and do use the same jig for ALL their Fritschi binding mounts. Older Fritschi jigs don’t have the extra hole for the Freeride Plus, but this can easily be located without a jig after drilling the other holes. Regarding the slightly different layout of the Explore screw holes, as I previously mentioned this small difference is easily absorbed by the screws shifting while they’re tightened, so the mechanical jig works for all Fritschis. Nonetheless, we did change the layout of the front screw holes on our Explore paper template to reflect front screw layout measured off actual production bindings.
As for the distance between front and rear binding units, we’d measured that off our retail paper templates and it was slightly off compared to the mechanical jig, which shows the layout to be about a millimeter farther apart than that on our paper template. Where necessary I corrected our Fritschi templates to reflect this. The binding is tolerant of this much variation in mounting dimension, but best to get as close to perfect as possible so errors don’t compound.
Speaking of bindings, let’s move on to a few Dynafit questions. This one from author Ted Kerasote in Jackson. Answer follows question:
Hey Lou:
Hope this finds you well. I couldn’t help writing since the opening page of your blog shows the parking lot at Teton Pass, and there I was yesterday afternoon, trying to hitch a ride down while the wind blew and the temperature fell below zero. Harsh. We had gotten a ride up, knowing that there’d be no parking, and, of course there wasn’t. That the FS didn’t approve the shuttle bus is beyond belief.
I was also checking out your website for some mounting advice, but couldn’t find what I was looking for in your excellent Dynafit mounting page. I just bought a new pair of Scarpa Spirits, and the shell size is smaller than my old Dynafit Tourlite 3s, so I’m going to have to move the rear binding, or the front, or perhaps both.
When I put the Scarpas on my Dynafit Freeride Carbon 10s (last year’s model), the center line on the boot is 4 mm in front of the center mark on the ski. When I put the Scarpas on my Volkl G4s, the center mark on the boot is 15 mm in front of the center mark on that ski. To make things more complicated, the center mark on the Volkls is 40 mm farther back than the one on the Freerides, even though they’re both 168s and virtually identical in their dimensions.
Now I’ve heard that some people are mounting last year’s Freerides with the binding a bit farther back, putting the center mark of the boot behind the center mark of the ski, because the ski’s a bit stiff, and they say it skis better, keeping the tips up more. What do you think of that? And I was wondering if the reverse logic would work on the G4s: move the binding forward and they’d ski quicker.
Do you have any advice about mounting these two skis with the new boot, and should I be worrying about the pivot holes on the boot being behind the ones on all the other Dynafit compatible models–supposedly to give a better gait while touring?
Ted
Hi Ted, I’ve seen that question come up frequently. Not only will changing your shell size frequently locate your boot in the wrong place on the ski, but one of the selling points for the Spirit is indeed that the Dynafit toe pivots are located slightly farther back than other boot models. This is intended to make a more efficient gait/stride, and it does. But the relocated pivots makes the boot effectively shorter as related to the Dynafit binding mount position. Thus, as you discovered, most people who upgrade to the Spirit will need a binding re-mount if they want their boot to stay on the ski’s boot location mark.
As for where you should be on the ski, it’s my belief that for backcountry skiing most people will like skis better if their boot is located on or behind the recommended position. Being ahead of the position can sometimes makes the ski feel “quicker” to turn, but makes it tougher to ride powder and crud in relaxed style. That said, it’s my belief that differences up to about 3 millimeters in boot position make little to no difference for most people, more than that and position should be corrected. Today’s skis can easily tolerate multiple sets of binding holes, so remount the bindings.
As for tweaking your position to be ahead of the recommended mark, for guys of our vintage I don’t see any reason to make a ski quicker — at least for me the things seem to behave more like wild animals every new season. Tame the wild things by keeping the mount position on or behind the mark on the ski unless you feel the ski truly has problems with initiating a turn. In that case perhaps try one centimeter ahead of recommended position.
Comments are on if anyone else cares to give Ted some ideas on where to go with all this.
Comments
12 Responses to “Backcountry Skiing Binding Conundrums”
Got something to say? Please do so.
Having turned screws in a ski shop for several seasons I have found that often the midsole mark on skis is sometimes incorrectly marked on the topsheet. I recommend measuring out the midsole mark on the skis then seeing if you are still mounted incorrectly especially on the G4s because 15mm seems like a pretty big jump if your old boots were mounted correctly.
At the least, always measure the distance of the mark on ski from the ski tail, and make sure both skis are the same. If not, I usually average.
This raises a question I’ve had for a while… how do ski rental places (with a multitude of boot sizes) center their bindings? is it bases on a average boot or is their something more to it.
I’ve been using the Scarpa Spirit III this season and already the new toe pivot point feels like the “right” one and all the older boots seem way off. It’s suprising how much of a difference 4mm can make! I haven’t had to remount any bindings because of it. The TLT’s just make it and the Comforts clear it easily.
Ricky:
Rental skis have the bindings mounted on a plate that allows the toe piece to move to accomodate various boot sizes.
Hey Lou,
Thanks for affirming what I told Ted @ the shop. We are going to remount his TLTs 2cm behind boot center on the ski. Word.
Hey, who’s that other guy…an imposter?
You guys with common names should try to be a bit more unique. Use an initial or something.
Yeah, 2cm behind ski mark, then he’ll feel the Zen.
You say that differences up to 3 mm in boot position do not matter to most people. Do you mean mm or cm? 2.54 cm = 1 inch. so, 3 cm is just over an inch, and 3 mm is just over one tenth of an inch. It would seem that moving the boot a lot more than a tenth of an inch would not make any noticeable difference. I think Russell Rainey has said that even moves of an inch or more are not noticeable (IIRC, the spaced the holes on the hammerhead so that teh distance between the holes – fore and aft – was the minimum binding relocation that he though would be noticeable). Anyway, just curious because I am thinking or relocating some bindings and am debating how far to move them.
I was being conservative, in the context of when to start being concerned about boot position if it changes because of a binding. In my experience, good alpine skiers can detect pretty small differences in boot position, canting, etc., so it’s good to not get sloppy with this. I don’t know about telemark skiers, which is what Rainey was talking about.
At any rate, about 3 millimeters is the standard I’ve come to use through experience for myself. Perhaps it’s too strict, but better safe than sorry. For most people, for backcountry skiing soft snow, I believe there is more tolerance if the binding is farther back then farther forward.
I’m also using the Spirit 3 and agree with Andrew, the 4mm makes a difference. One important note: I’ve found that the Dynafit jig does not mount TLT Classics correctly for the Spirit 3. With other boots the jig places the toe and heel far enough apart that the heel needs to be almost in the far forward (smallest) position, but with the Spirit 3 even the smallest position is not small enough! If you get the Spirit 3 and use TLT classics make sure the shop knows this, or mount them yourself.
And people wonder why we go to the trouble of supplying paper jigs and instructions that if used correctly place the boot and binding in the proper position no matter what…
In my experience, the Volkl (and Atomic) midsole marks tend to be considerably further back (1 – 2 cm) compared to other ski makers. This seems to be even more the case on somewhat wider models, which the G4 was at the time.