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Dynafit Release Adjustment Tips and Tricks

By Lou

Part Five in a week of Dynafit. Without you esteemed blogsters commenting on it, I never would have realized that all these years I’ve been setting my Dynafit release somewhat by instinct. I’ve always been certain how the horizontal release scale worked, but for the vertical numbers I’d just assumed the tiny raised plastic hatch marks (ridges) were somehow a scale of 5 to 10, and that the big printed numbers were there to call attention to how the hatch marks were scaled.

Then I looked at the binding and thought about it. Sometimes that’s dangerous. The thinking, anyway. The more I looked, the more confused I got. So I contacted my sources this morning. Yep, the hatch marks are the settings, the big printed numbers just indicate the range of the marks. Check out the photos.

Dynafit binding safety release scales. Upper scale is for vertical release, lower for lateral (side).

Use a small screwdriver in the upper recess to adjust vertical release. Large bladed screw driver works well to twist lower adjustment barrel.

For ultimate safety, it’s useful to adjust vertical and lateral release values independent of each other. In other words, use a chart to figure out your DIN number, then set your bindings perhaps one number below that. Ski the bindings. If you have an unnecessary release (prerelease) just dial up the binding for whatever mode that release was in (vertical or lateral) and leave the other setting alone. I’ve found that I can leave my Dynafit lateral setting quite low, but need to keep the vertical setting at or slightly above what the DIN chart recommends. For extreme skiing when loosing a ski could kill me, I dial everything up 2 or 3 DIN numbers above my usual, and when on the actual danger terrain I use the touring lock which blocks lateral release up to around DIN 15/18 or so my sources say.

One other thing about adjustments: The space between your boot heel and binding is CRITICAL. It’s 4 mm for TLT models, 6 mm for Comfort/TLT/ST. BUT, do not set this by trying to use a ruler, you must use the feeler gauge included with the binding. See our Dynafit binding FAQ and other articles for more about this.

All this leads to one of the more cryptic bits of Dynafit trivia. What do the “MY” and “MZ” printed on the side of the binding mean? They obviously attempt to communicate which is the vertical release scale and which is the lateral. But, is this some sort of insider Tyrolean engineering thing or what?

So, I emailed Fritz Barthel, inventor of Dynafit bindings. Here is what Mr. Barthel says the origin of the terms is:

Lou,

This derives from the (cartesic) coordinate system for a boot-binding-ski system that is used in the ISO standards. The z-direction of this coordinate system is pointing “upwards” (direction of the shin bone ) therefore a torque (rotation) around this Z axis applied to the boot is the torque needed for lateral release. The Y direction is “sideways.” A torque around this axis applied to the boot would open the binding in vertical direction.

Thus, “Mz” = momentum (torque) around the z-axis, “My” = momentum (torque) around the y-axis.

(Editor’s note: The confusing aspect of this is that while the Z axis is vertical and the Y horizontal, the marks on the binding end up being the opposite, with MZ meaning lateral release (because this actually means rotation around the vertical axis, and so forth for MY.)

In the standards the release values are defined as torque (and also measured by the TÜV with devices that apply “torque,” also for front release.) E.g., a setting of “8″ for the lateral release would mean that a torque of 80 Nm on the boot should open the binding (plus/minus some tolerance). The “forces” to hold the boot then depend on the “lever,” in this case the boot.

That’s why the tables in the manuals compensate for the length of the boot changing the torque. The standard settings end with “10,” everything beyond that value is not covered by a standard. “10″ means 100 Nm, which is the equivalent of a bucket of water hanging on a lever with a length of one meter. Imagine you hold your foot horizontally, the lever is attached to the boot and you try to lift the bucket of water through rotating your leg. “20″ would mean 200 Nm, nobody is able to open such a binding statically (in slow motion).

Fritz

Posted by Lou on December 5, 2008 | Filed Under Binding Reviews, Technique

Comments

28 Responses to “Dynafit Release Adjustment Tips and Tricks”

Chris December 5th, 2008 12:09 pm

Here’s my guess based on how things generally work in the automotive world:

“M” actually represents “Moment” (think torque if moment is unfamiliar) and not magnitude. The Y and Z are axes. Usually, the X-axis runs longitudinal, the Y-axis laterally, and the Z-axis vertically. So, “MZ” would refer to a “Moment about the Z-axis”, and this indicates the lateral release since the boot (and heel piece) actually pivots on the vertical axis to release laterally. Likewise, “MY” refers to “Moment about the Y-axis” indicating vertical release since the boot pivots around the y-axis to release vertically.

Like I said, just a guess, but it makes sense to me.
Mark December 5th, 2008 12:28 pm

I have been skiing dynafit bindings for about 4 seasons now, and have been very happy with them for the most part. I had been having some minor trouble with pre-releasing problems, so I had the release tolerances tested at a shop here in Boulder; they came back perfect. So I slowly dialed up the dins (both vertical and horizontal). This past spring I had dins set to 9.5 (10 is what the charts recommend for me). Then, returning from a ski descent of Toll, I had an awkward fall in some deep soft snow. My left binding released easily in a horizontal plane, but then I fell directly over the tip of my right ski, putting extreme pressure on the vertical release of the right ski, which never broke free. The result was a third degree strain (tear) in my right calf, followed by an extremely painful 1.5 mile exit, then two weeks of not walking and now six month later I am still feeling some pain and weakness when flexing that calf. I’m getting ready to ski again but I will definitely be lowering the vertical release din setting before doing so. Just thought I would share this story and see if anyone had any thoughts or recommendations.
Thanks
Sam Reese December 5th, 2008 1:45 pm

I thought for some reason that M was for modifier, as the spring is constant, you change the spring’s properties by modifying the pre-load on the spring.
GeoffA December 5th, 2008 3:15 pm

I had my bindings mounted by a shop that tests the actual DIN. They found that the vertical release had to be set +1 to get the proper release characteristic. They told me that if I adjusted them that the +1 is approximately constant. I’m small and light so my DINs are at 6.5 and 7.5.

As for the naming convention, Chris’s guess seems pretty good to me.
Jonathan Shefftz December 5th, 2008 3:45 pm

Just to confirm: are you calling the “ridges” or the “valley” the hatch marks?
jerimy December 5th, 2008 3:50 pm

I think it would have to be the ridges: 6 DIN settings (5-10) and 6 ridges. Where as there are 7 valleys.
Lou December 5th, 2008 4:05 pm

Jonathan, you sure keep me honest! The ridges, my friend. I’ll edit the post to reflect that. Lou
AK Jack December 5th, 2008 9:51 pm

Thankyouthankyouthankyou. Great post on D-fit release beta!
AK Jack December 5th, 2008 10:05 pm

TO MARK:
Did the same thing, but got a grade 2 calf strain in my layman’s estimation. Only missed about a week of powderplay. I ski about 90 days/yr; 1/3 each front country, backcountry, and alpine – my alpine (big Salomons) would have definitely double ejected, but one of my D-fits did not in my incompetent creek crossing in a whiteout..

Same solution, relaxed vert release. I went a little overboard and prereleased (& banged my knee.) As a 25+ yr 2-planker AND Dynafit ROOKIE, I’m hangin’ in there with the D-fits cuz they’re light (even if semi-releasable.) Trying to take Lou’s advice: Don’t fall.
Lou December 6th, 2008 8:39 am

Guys, please don’t call a binding “semi releasable” unless you call every binding that term. A constant stream of ambulances comes off the ski hills around here, and the orthopods all have toys such as private planes, all because of people using their “sem-releasable” alpine bindings and various AT bindings. I know of injuries that have happened over the years on virtually every modern AT binding, for example.

I’ve hurt myself on everything from nordic racing bindings to alpine bindings, with plenty of injuries on AT bindings mixed in there.

Binding release in general is primitive technology that’s basically been the same thing for decades, and they don’t release at every angle nor do they always release at a low enough force to prevent injury. That’s just the reality of the situation.

AT bindings have their release pluses and minuses. For example, I’ve never been impressed with the lateral release of the Fritschi. It always seems to have too much friction, and not much elasticity. Dynafits have an incredibly smooth and elastic lateral release, but the vertical release doesn’t have as much elasticity as bindings with over-center pivot heel unit such as Fritschi and Duke.

For example, Duke allows your heel to move upward just over a centimeter before you go past the point of no return and release. Dynafit allows upward travel of around 3 millimeters before you pop out vertically. In my opinion, this difference in elasticity means some skiers may need slightly higher or lower vertical DIN settings on a given binding, depending on their style of skiing.

And some skiers do seem to need really high DIN numbers no matter what binding they ski. In my opinion that’s fine when you’re drinking the wine of youth, but is not sustainable for a long lifetime of skiing.

The difference also makes the bindings feel different when you ski them. For example, the incredibly solid and precise feel of the Dynafit might in part be due to how little your heel moves up and down when you ski, as compared to a binding with more elasticity/slop.

Bottom line is yeah, if you’re falling you’ll eventually find out an angle and force that your binding _doesn’t_ effect a release for. Cripes, you can blow out a knee or pull a muscle hiking without skis…

Someone said a while back on another thread that if everyone was more careful with their DIN settings, the epidemic of ski injuries would take a dive for the better. I agree with that. Again, the bindings are not perfect, but it is IMPORTANT to ski with the lowest DIN possible, and if you’re falling more than a few times a season, don’t expect the odds to be in your favor.
Graeme December 6th, 2008 3:59 pm

Lou, any word on whether the presence or absence of brakes affects the vertical release DIN?. It is clear how the springs can be changed or the DIN adjusted for the lateral release, but no mention in all I have seen of vertical release. Are you aware of any formal testing of vertical release with/without brakes?
AK Jack December 6th, 2008 5:52 pm

Sorry, Lou. You’re right, all bindings are semi-releasable, even the ones that aren’t designed to release at all (had a few mechanically fail, come open, & pull out of the ski). In my case with Dynafits, it was human error on my part in setting my Dynafits that yielded the ’semi-release’. By semi-release, I meant one binding released and the other binding did not – post fall inspection revealed that one of my MZ settings was slightly higher than the other.

I’m still really liking my Dynafits. As a free-heeler until last spring who made the move to AT, I needed more education on how they work. And your wonderful blog (and an Alaska Mountaineering & Hiking tech) really helped educate me. Thanks, again. Jack
Lou December 6th, 2008 7:34 pm

Hey Jack, thanks for being here!
Lou December 6th, 2008 7:38 pm

Graeme, I don’t think it makes much difference in vertical as the brake kind of retracts at a certain point with very little upward force. It’s more of a concern because of added friction for lateral release. Most people don’t pay much if any attention to this, but it’s worth considering if you run higher than normal DIN. I guess the FT12 is already calibrated for this, as it comes with brakes.
Graeme December 7th, 2008 3:02 am

Thanks, Lou – I was sort of presuming this to be the case, in the absence of other info, but its nice to get it confirmed. I am actully using a couple of sets of last year’s FTs, DIN 10, but I have removed the brakes from one set which is an ultralightweight setup.
Mark December 9th, 2008 2:26 pm

Thanks for the info Lou. I know there is no perfect solution, just looking for suggestions and expertise. As I have entered my late 30’s I do try to keep my falls/season in the 2-3 range, seems like I just got a bit unlucky during this one awkward fall. I’m still worried about my injured calf, so I plan to lower the din on the vertical releases. Otherwise, I love the bindings and will stay with them, I’m just always looking for a better/safer setup, or any ideas from those more experienced than myself.
Lou December 9th, 2008 2:42 pm

I’d just fine tune that DIN, and realize no binding is perfect.
David December 22nd, 2008 2:55 pm

One more vote for a lower setting on the vertical release. Had some experiences where I thought the vertical should have released, but it didn’t. No injuries though.
This was when using the same setting on both lateral and vertical, and the lateral released just the way that I wanted to. Now I go about 1.5 step down on the vertical setting.
Bill December 30th, 2008 12:31 am

I’m looking at Dynafits for the first time. Is the lateral release pivot point heal based? Meaning in alpine bindings and on my Naxos, the toe pivots for a lateral release. Looking at your article, it appears that the pivot for the Dynafits is at the heal.

BTW, great articles and videos on the Dynafits. They have been most helpful.
Lou December 30th, 2008 7:14 am

Bill, heel mostly but a bit in the toe as well, a very smooth lateral release. See our index to many Dynafit binding articles, and be sure to use our search function as well.
Jason Gregg February 21st, 2009 10:10 pm

I was just dialing up my vertical release DIN on my TLT Verticals up to 10/max and when I tried to back off half a turn the screw sort of stripped. Now the head of the screw is all the way backed out (all most flush with the rear surface of the heel piece) and the DIN is at the minimum. Do you think this is repairable or covered by warranty?
Lou February 22nd, 2009 2:22 pm

Jason, it’s repairable, but I don’t work for Dynafit so I’m not clear on warranty issues. You’ll have to contact them for that…
Jurek March 14th, 2009 10:58 am

Hi Lou,
In one of your posts you wrote about removing the inner spring as a method of moving down the range of the lateral release settings. Did you measure the value by which the DIN setting decreased after that trick?
I bought Verticals FT12 recently, and because of my rather low weight (65kg) and the torn (a year ago) ACL I’d like to decrease the lateral release force below DIN 6. To determine the force change obtained by removing inner springs I did the following test: one of the heel units (the one without modifications) set for DIN 6, and from the other removed the inner spring and dialed such value to have subjective feeling (twisting heels units manually) the forces in both heel units are the same. The value was about 7.5, what means that removing the inner spring decreased DIN value by about 1.5. So setting 6 on the scale, without the inner spring give us DIN about 4.5
Do you think I am right? Regards from Poland.
Lou March 14th, 2009 7:12 pm

Jurek, one has to ask, if you only need DIN 6 or below why in the world did you buy FT 12 bindings?

As for how much using one spring lowers the DIN, I don’t know the number but my feeling was that it lowered it quite a bit, at least 1.5.
Jurek March 15th, 2009 2:29 am

Thanks for the answer, Lou. Yes, I rather should have bought Verticals ST or one of the earlier models, but I hit the FT for a good price. And from the other hand – they are beutiful…
Cameron April 19th, 2009 1:28 am

Lou,

I am having a problem with my dynafit comforts releasing while in the touring lock mode. While skinning some steep slopes they have been popping out while the front tab is pulled up and locked. Do you have any recommendations?

Thanks,

Cameron
Lou April 19th, 2009 5:56 am

Cameron, what boots, body weight and conditions? Any chance either the toe sockets were icy or dirt packed, or that you had ice in the pocket under the binding toe wings? Does this happen any conditions, any day? And how often?
John May 7th, 2009 9:13 am

I have a set of FT 12 bindings on Atomic RT 86s. The instructions call for 6mm of heel clearance. At 6mm I can flex the ski up to the point where the pins pull out of the boot heel fairly easily. My main concern is overflexing the ski in the other direction, say while dropping into a chute, and pushing the boot out of the front mechanism. At 4mm I can get pretty close to simulating this.

The relationship between vertical release setting and heel clearance is readily apparent.

What heel spacing do you guys run on your FT 12s?