G3 — Stomp Pad and ZED Binding Gaposis Breakage

Post by WildSnow.com blogger | December 8, 2018      

This post sponsored by our publishing partner Cripple Creek Backcountry.

In downhill mode, showing stomp pad.

G3 ZED in downhill mode, showing stomp pad gap exceeding their now recommended 1.5 mm gap.

I’ve never been entirely convinced on the use of stomp pads with classic tech bindings such as G3 ZED. (Stomp pad being a block of material under the boot heel, with a small gap that closes up when the binding heel flexes downward under high loads).

A couple of reasons for my skepticism: Mainly, I knew that boot’s vary in shape, so getting the correct stomp pad height is difficult (leading to the dread medical condition known as “gaposis). More, stomp pads are a kludgy solution to inherent binding fragility.

I’d rather see a binding be strong enough, and not need the pad for all but the biggest, most aggressive skiers.

Thus, while doing my examinations of the G3 ZED, I gave a sagacious nod to the stomp pad, figuring “well, here we go again, but I’ll shut up and see what happens.” Apparently, what happened is indeed the ZED fixed-height stomp pad ran up against the reality that the ski touring boot industry doesn’t have much truck with the DIN-ISO standard for ski touring boots. (In my opinion a good thing, as we wouldn’t have the plethora of cool boots if they had to conform to 9523).

So, a guy breaks his ZEDs, ostensibly due to him not using the stomp pads. The breakage is published on an internet forum, and G3 discovers that indeed their stomp pad situation is problematic.

Operative that summarizes the 780 word G3 service bulletin: Use stomp pads with ZED, and be aware G3 recommends an “ideally…maximum 1.5 mm gap between the ski boot sole and ski brake or stomp pad when unweighted.”

Further, G3 states the following in their service bulletin:
“To address the potential scenario where non-conforming boots are used with the ZED binding, G3 has developed two additional stomp pad height options which will be available on December 19, 2018. The optional stomp pads will be 1.5 mm and 3.0 mm higher than the standard ZED stomp pad that has shipped with all currently available ZED bindings. These additional items should address any outstanding sizing needs at this time.”

Above is okay, though odd. If you examine the ISO standard, you’ll see it allows <>2 millimeters variance (latest version) in boot heel height. That means a boot could still be “norm” and exceed the 1.5 mm gap needed to make ZED reliable. Further, there is no norm or standard regarding the exact vertical position of the boot heel tech insert. Change the vertical position of the heel fitting, and the height of the boot heel changes while in downhill mode. In other words, a boot doesn’t have to be “non-conforming” to have dimensions that cause excessive gap above the original ZED stomp pad — because of allowed variation, as well as the position of the heel tech fitting NOT being part of the norm.

Further, the G3 communique states that “We were unaware there are many alpine touring ski boots in the market that do not conform to the recognized industrial norm for positioning tech inserts in their boots.” That’s a jaw dropper for me, as I thought it was common wisdom that boot dimensions are all over the map. But then, tracking the plethora of today’s ski touring boots is indeed a daunting proposition. Total sympathy from here, as I’m always overwhelmed with the explosion in touring gear options.

In my opinion ZED is still a player (though indeed being a first-year tech binding, which we never recommend) but be sure you configure the stomp pads correctly. I inferred from the bulletin that the ZED brake somehow doesn’t have the “gaposis” problem, but in my view you would want to be sure the gap between brake and boot sole was no more than 1.5 mm as well.

As always, kudos to G3 for dealing with this situation in their usual responsible fashion: upfront, open, a detailed bulletin. A product recall is unnecessary in this situation, but I’ll be expecting an adjustable height stomp pad to appear in ZED 1.2, perhaps similar to the adjustable “Freeride Spacer” ATK has come up with. ATK infos here.

I have to admit in getting a chuckle from this debacle. As I’ve been getting some flak about my credo: “avoid first-year tech bindings like the plague.” Well, here you go… Early adopters, check your stomp pads!

Historical note: This isn’t the first the heel height of non-norm boots, or norm conforming boots with the <>3 mm variance, caused binding problems. I recall a situation many years when a binding model’s brake did not work correctly with quite a few boot models, due to heel height issues. And I remember another time
some boots would not click into a binding due to heel height.


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22 Responses to “G3 — Stomp Pad and ZED Binding Gaposis Breakage”

  1. Lee Lau December 8th, 2018 6:35 pm

    I’m with Lou. Use any first year tech binding AT YOUR OWN RISK. Even if they call it “production” and use words like “extensively tested”

  2. Evan Stevens December 9th, 2018 8:32 am

    FWIW I toured well over 500,000′ on some Zed’s last season. I’m 185lbs with out all of my gear. No stomp pad last year or brakes, I’d like to think I ski aggressively, all in good snow. I’m skiing them with out any hesitations.

  3. atfred December 9th, 2018 10:21 am

    Hi Lou,
    a bit off topic; two din setting questions:

    1) is skier weight with or without clothes/gear/pack?

    2) are recommended din settings pretty consistent among binding models within the same brand (e.g., all dynafit)? I assume not so among brands.

    Thanks much,


  4. Gary S December 9th, 2018 11:06 am

    Thanks as always Lou! Curious to examine further the next Zed we mount at Cripple Creek. Most customers have been opting for brakes FWIW. I’m assuming the stomp pad was omitted due to fears of created a “dead spot” akin to a frame binding? May have legitimate concerns there as the stomp pad so small and heel lugs in sole treads can be quite aggressive. Am i picturing this potential scenario correctly where heel lug of a boot is not sliding freely on the stomp pad therefore not utilizing the rearward travel of the Zed unit?

  5. Lou Dawson 2 December 9th, 2018 3:12 pm

    Evan, usually pre-retail product is different, not the same manufacturing run, not the same injection molding run. So it’s good to know your bindings were that strong, but unwise to translate to the retail version that G3 says need a stomp pad, in my opinion. Lou

  6. Martin December 10th, 2018 8:05 am

    That is why ATK sells an adjustable stomp pad, which they call Freeride Spacer:

  7. Lou Dawson 2 December 10th, 2018 8:13 am

    Martin, um, as in the third to last paragraph in the blog post (smile)? Lou

  8. XXX_er December 10th, 2018 11:28 am

    AT boots have been suspended between the pins with no stomp pad or brakes by many of the people who read this forum for decades so to suddenly claim a tech binding need a stomp pad sounds like lame damage control in a high drama situation

    When end user breaks both heelpieces on the binding’s inaugural run at < 15mph it sounds more like new defective heelpieces to me

  9. wtofd December 11th, 2018 12:51 pm

    To be honest, a sponsored athlete claiming last year’s prototypes were bomber doesn’t tell us anything about the problems with this year’s product.
    Just seems strange that everybody says the stomp pads aren’t structural until a week after the first heel breaks. Now they’re structural. Doesn’t add up.

  10. Evan Stevens December 12th, 2018 1:01 am

    Literally why I started my post with FWIW…I know my thoughts are to be taken with a grain of salt! But at least I care enough to follow along on all of these tech discussions, have these same discussions with the engineers and hammer on things and test out these thoughts.

  11. wtofd December 12th, 2018 7:25 am

    Evan, thanks for the response. Didn’t mean to sling mud, but I am curious about what actually happened. Do you have a suspicion about causes for heel failures? I noticed that you included “good snow” in your comment, which I took to mean soft or light. Is that fair? Would you hesitate to take them on “bad” snow?

  12. Harkin Banks December 15th, 2018 11:09 am

    Stomp pad aside, I think it’s interesting that no one is really talking about the other issues with the Zed: Heel elasticity/movement while ascending and the toe height incompatibility with the Ion crampon. I really want to like the Zed, but I find that the heel movement in tour mode is more than annoying, but inefficient. Has anyone else encountered this problem? The Ion LT has a feature that locks the heel into place while touring (ie. no movement). Next, with the lower toe height on the Zed compared to the Ion, the Ion crampons sit up to high to allow for crampon use without the heel risers.

  13. XXX_er December 15th, 2018 2:12 pm

    I’m still on Verticals ( thankfully ) so I haven’t tried ZED or ION, SO are you saying the ZED heel piece is sloppy on the skin up Harkin Banks ?

    So wouldn’t it also be sloppy on the down ?

  14. Harkin Banks December 15th, 2018 11:45 pm

    XXX_er, the forward pressure of the heel is a great thing on the way down (maintains a release value in relation to the flex of your ski), however when that same heel isn’t locked in place in tour mode (1/4 turn) on the way up, the heel tower tends to move/flex back when weighted. At first this only happened on steeper sections with the first riser up, but once in a while I would get snow buildup below the heel of my boot, and the binding would move/flex back on gentle slopes without the risers. For comparison, I also have a pair of Dynafit Rotation 10 bindings (which have forward pressure in the heels), and I have never had any issues with heel tower movement while skinning.

  15. Kyle December 17th, 2018 3:38 pm

    Harkin Banks,

    I, as well as a friend, experience the heel getting pushed back when skinning… What is funny though, is it not 100% predictable. I usually get it when side hilling, sometimes straight up, but not always. Sometimes I can stomp on it HARD and it doesn’t do anything, other times I can weight my heel and get the tower to slide back far enough to let the riser come out from under the heel… It’s not always like this though… My main thought is friction in the form of water (or lack thereof) against the sole of the boot… When the sole/lifter is some kind of wet or frozen, it slides back?

    I am 150lbs and ski Salomon MTN 95s with Scarpa F1s

    It is annoying and inefficient. My third concern is how this travel will impact the release value or prematurely fatigue some springs in the heel? My fourth concern is that sometimes when this slips, I get a small amount of rotation through the boot as well.. The lifter will slip between the lugs of the F1 sole and slightly rotate the boot outward at the heel… What kind of torsion is this applying to the shell and the toe of the binding? Can’t say I like the thought.

  16. MikeyC December 19th, 2018 12:53 am

    I am an early adopter, basically i keep my hear forever and figured i would trust G3 to manage any shortcomings and not spend the next decade or two on already old bindings. i do have my old gear to revert back to if needed. I just opened up my Zeds and looks like my new Solomon SLab boots have 3mm clearance so some new stomp pads will be on order shortly. I measured up the mounting hole pattern to your Ion binding template and both toe and heel are a perfect match. I could not find mounting info elsewhere on the internet so thought you could update your template title to cover both models.
    Quick question, with the 30mm adjustable track, should i just mount with the binding in the center? Any reason to bias the track fwd or back?

  17. MikeyC December 19th, 2018 1:05 am

    I read HB’s post about the heel movement above. Looking at my pair, the DIN maxes out when the tower twists into tour mode, maybe they were trying to have the tower act locked out without another switch to flick/break?

  18. Mark December 24th, 2018 4:01 pm

    The backward heel movement when climbing is annoying and worrisome. As mentioned above, seems to be torquing both the toe unit and the risers. 🙁
    Has anyone come up with a solution?

  19. Carol December 30th, 2018 11:48 am

    Interesting reading the Zed issues! I have a pair but haven’t mounted them on skiis yet. The stomp pad gap is 1 mm for my boots. I know that the boot should not rest on the pad, but other than that, is there a minimum acceptable gap?

  20. MikeyC January 2nd, 2019 12:31 pm

    Hi Carol, I was just reading over the G3 ZED Service Bulletin (https://www.genuineguidegear.com/zed-service-bulletin) and they state that so long as you have less than 1.5mm gap you are good to go so you should be fine at 1mm.

  21. ALEX BLARDONE April 3rd, 2019 3:34 pm

    The issue of boot sole variation is a lot worse when you combine the Zed bindings with the “compatible” ION crampons. With the crampons on, the boot is propped up above the heal riser by the crampon hinge.

  22. Kyle April 3rd, 2019 3:56 pm

    ALEX BLARDONE, as spring has finally come, I have used crampons with the Zeds and Fischer Travers carbons. There is some contact but it is minimal for me. G3 told me that they are aware of the issue.

    I may file a small amount off my “crampon towers”. Of course this will be out of warranty.

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