Tech Binding — Zero Heel Gap Powder Frustration

Post by blogger | June 6, 2018      

Any of you use ski touring tech bindings with zero tech gap at the heel, what we call the “kiss gap,” and had trouble clipping your heels down when you’re in deep soft powder? Here is the deal:

Kiss gap set on G3 ION.

Kiss gap set on G3 ION.

Entering ION with ski flexed.

With kiss gap set, if you somehow flex your ski when stomping your heel down as you enter binding, the shortened distance created by the flexed ski causes your boot heel to land something like this. Both the boot heel and the ski touring binding need inclined “ramps” to help with this situation, to lead the boot down into the binding utilizing the “ski flex compensation” built into all bindings with zero gap. Shown above, the ION binding has an angled lead-in ramp to mitigate or eliminate problems with step-in.

New Marker Alpinist set with kiss gap.

New Marker Alpinist set with kiss gap. Note the binding lacks a lead-in ramp, so it’ll depend entirely on the heel of the boot having a ramp shape. I find it odd the Alpinist has the small tab of plastic that’s set close to the boot with the kiss gap, while there being so much space between the lower binding and the boot heel. Perhaps an effort to reduce friction during lateral release?

As the Alpinist binding does not have a ramp, this is what your boot heel can do.

As the Alpinist binding does not have a ramp, this is what your boot heel can do if you attempt to clip in with a flexed ski. If your ski is not heavily flexed and your boots have plenty of ramp you might not notice the effect, but we’d prefer to see the binding help with this as well.

Detail of Scott boot heel.

Detail of Scott boot heel. The rubber has a nice ramped shape, but I’d prefer a smoother transition to the steel tech fitting.

A TLT 7, very little ramp, easy fix.

A TLT 7, very little ramp, easy fix.

Tiny trim makes a nice ramp.

Tiny trim makes a nice ramp.



Vipec, nice lead-in ramp.

Vipec, nice lead-in ramp.

Dynafit Radical 2 is set with kiss gap, has a nice ramp.

Dynafit Radical 2 is set with kiss gap, has a nice ramp. Radical “1” models are confusing in this regard. Many of the later ones have ski flex compensation, are set to kiss gap, but don’t have a lead-in ramp and thus can present this problem of the boot heel being blocked when clicking in on a flexed ski. Earlier Radical bindings were set at a 5 mm gap, thus not needing any sort of lead-in ramp.

If you’re an average to smaller skier and don’t end up clicking in while standing on soft snow, you might have no reason to consider all the above. On the other hand: if you ever find yourself stomping your heels down over and over again without that satisfying tech binding click, wondering what the heck is going on, now perhaps you know.

My opinion about all this? I’m still a fan of the astounding simplicity in the basic tech binding that uses heel gap for ski flex compensation. I’m not quite sure why so many companies go to so much trouble ignoring that and creating various spring loaded machinery that appears silly in comparison. If you’re going for TUV certification to ISO-DIN ski touring binding standard, you do need ski flex compensation, but very few tech binding makers go to the trouble of TUV. One consideration is that the binding release/retention setting does slightly change when a classic tech gap widens or narrows as the ski flexes, but I’ve never seen that as a big concern. Mysteries of the universe, I suppose.


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14 Responses to “Tech Binding — Zero Heel Gap Powder Frustration”

  1. Andrew B. Carey June 6th, 2018 10:00 am

    Nice write up. I’ve encountered this problem even with bindings that require as much as a 4 mm gap, my Plum Guides, for exampple–setting a small gap precisely requires not only proper technique (for the Guide the spacing rod is laid horizontally across the pins), precision, and patience and, for me, repeated fitting of the boot in and out of the rear heel piece. Tightening the 2 screws on the Guide and Yak has to be sufficient to prevent movement but not so great as to strip the screws/nuts. And some very good thread locker must be used to avoid surprises while skiing. I had some with both bindings, but not with Superlite 2.0s so far.

    I (as was discussed in earlier posts) had to trim the rubber sole on my Scarpa F1s to avoid hitting the heel post on Superlite 2.0s in post-holed and runneled snow and I had to deepen the pin slots on my TLT6 to meet the 4 mm gap and still accept the pins of the Guides when the snow was soft!

  2. VtVolk June 6th, 2018 10:16 am

    I apologize if this has been covered before, but I thought we were supposed to leave a few mm of gap to help ensure proper release. My Dynafits came with a little red plastic spacer to help with setup. Is the “kiss gap” now standard?

  3. Lou Dawson 2 June 6th, 2018 10:26 am

    Hi VT, some bindings require zero clearance kiss gap, some require 4 or 5 millimeters. Depends on brand/model. See links in the post. If your binding came with the spacer then yeah, you want the wider gap. It’s all quite confusing and a good reason for specialized retailers to continue to exist… Lou

  4. Felipe June 7th, 2018 7:06 am

    Hi Lou,

    Should the gap in tech bindings set applying no downward pressure on the ski ?

    Is this more problemtic in skis with high underfoot camber?


  5. Lou Dawson 2 June 7th, 2018 7:58 am

    Felipe, there is uncertainty about that, I adjust a lot of skis and I simply set them on the bench and adjust, seems to work fine. If someone insisted I would probably set kiss gap with ski held down flat on bench — though after doing so I would do the upside down test as described below. Thing is, in my opinion there is no reason to have any pre-load pressing back against the binding heel unit when the ski is in neutral flat camber position, but a little bit is not a huge issue. Think of it this way: with kiss gap, as soon as you load up the ski in a turn the boot ends up pressing against the binding heel, utilizing the compensation spring, so a bit of preload is just doing what the binding is designed to handle. Caveat with that is the tendency for binding owners to instinctually adjust, then give the screw a turn or two extra “because I ski hard…” Bad mistake with tech binding boot length adjustment.

    Another test for aggressive skiers: Adjust kiss gap, then flip ski upside down with boot in downhill mode, suspend ski between two supports such as a couple of chairs, flex ski aggressively, observe binding pins as they pull out of the boot heel fitting, if they come out too easily then you’ve got a concern about how the binding is adjusted, or the length of the heel pins, or both. This test simulates an energetic “de camber” of the ski, can happen for example if you do a jump turn or otherwise bring your skis up with heavy snow piled on the tips and tails.

    (The “upside down test” also illustrates how weird it can get trying to test upwards release if the ski is flexing.)


  6. See June 7th, 2018 8:21 am

    I’ve wondered for a while if tech binding heels that don’t have any fore/aft travel can bottom out against the boot hard enough to cause release at the toe when the ski is flexed hard. I’ve never observed it to be a problem with proper gap, but I have prereleased from fixed bindings with too little gap.

  7. Lou Dawson 2 June 7th, 2018 9:07 am

    See, exactly. More, too tight a gap with a non compensating binding heel can bust the binding. Certainly some of the rear binding breakage we’ve seen over the years was caused by this, not by weak bindings. Lou

  8. sherpa June 8th, 2018 8:45 am

    putting on skis in a local terrain similar to a hole is not recommended since skis were invented. it makes the step in obviously more difficult, the snap in/click of binding heel is problematic a whole ski is under complicated pressure, transporting this into bindings {wherelse?}. the ski tries to accommodate to terrain, but never quite very precisely, thus all those problems with step in. the very modern bindings try to be user friendly and comfortable too much beyond the ski nature and origins. step in anywhere and go uphill or downhill {just after getting of the car and making 1 step max.}. that is killing the touring and discovering nature of this sport. but money rules.

  9. Alex June 10th, 2018 8:57 pm

    I’ve a different problem related to the kiss gap with my IONs. In uphill mode with the heel rotated, while traveling through a small depression that flexes the ski, I’ve caught the binding with my boot heel as I raise my heel up in a forward stride. This has broken off a piece of the plastic cap of the binding heel. It’s not just cosmetic – that cap holds the spring under the heel lifters in place, and once it’s gone the heel lifters flop around with every step. I’ve had this happen twice, and currently have a twisted paper clip keeping the heel lifters mostly under control. The plastic is clearly designed well to handle downward force, but not this rare upward force. I suspect this is more common here on the east coast, where our shallower snowpack often closely follows the contours of uneven ground.

    Backing off from the kiss gap to a wider gap would probably solve the problem, but I’ve been worried about affecting downhill release. Sounds like it’s time for the upside-down test, and maybe some strategic boot sole trimming. So thanks for those tips!

    The shape of the ZED seems to be a bit slimmer in this area, perhaps to address my problem?

  10. Lou Dawson 2 June 11th, 2018 8:37 am

    Alex, the problem of zero gap (kiss gap) bindings “sticking” to your boot heel during foot-flat-on-ski mode touring is common. I believe it’s indicative of a couple of things

    1) Poor engineering, in design engineers overlooking that any time you change something on a machine, you’d better figure something else will change as well, in this case the change was going from the classic 4 or 5 mm tech gap to the zero gap.

    2)Solutions without a problem, in that why exactly do we need bindings with zero gap and ski flex compensation?

    3) Poor testing. Always amazes me a company can’t simply test their products enough to reveal simple problems.

    Alex, in your case, I’d try just a small gap of a millimeter or so, as well as some work on the boot heel. Easy to test at home, just clip into your skis and suspend between two 2x4s at tip and tail, stand on ski, simulate making a stride…

    A small gap instead of kiss gap is no big deal in my opinion, though you do need to be careful and do the upside down test while playing around.


  11. Nico December 15th, 2018 3:07 am

    Hey Lou
    I’ve started noticing now (especially here in Europe in paper magazines, yep we are still fans of those) that journalists start stating that having a spring in the heel gap for ski flex compensation is both a safety (“less risk of ripping off bindings”) and less harsh down experience.
    I was under the impression that 4mm gap vs spring was virtually the same but I might be confused? Or is Marker just doing a great marketing job? 😉


  12. Lou Dawson 2 December 15th, 2018 6:11 am

    Nico, I highly doubt the spring makes the ride any different than a properly adjusted gap, that’s just PR BS. As for durability, sure, an ongoing problem with tech bindings has been users not adjusting them correctly, I believe much of the heel tower breakage we used to see was caused by tech gaps that were too small, the spring makes the binding “idiot proof.” I don’t like the spring, don’t need it, but that’s just me. Lou

  13. Nico January 6th, 2019 12:47 pm

    Hey Lou

    Me again, thanks for your answer as always.
    I was discussing it with a ATK fan boys who swears that the crest has a 4mm gap and a compression spring. I fail to understand the point of having both really.


  14. Lou Dawson 2 January 6th, 2019 3:18 pm

    Nico, having both isn’t a bad idea, but yeah, not mandatory. I think quite a bit of what goes on with the compression (flex compensation) springs is they’ve become necessary due to a large number of people skiing without the binding tech gap set correctly. It is too much to ask of the average consume. Alpine bindings, same thing, the flex compensation is also there for variations due to snow on boots, dirt, that sort of thing. Lou

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