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  • Axl vs. Hammerhead: Ski Control

    Lately I've been considering how I might reduce the rocker launch that seems inherent in my Hammerhead bindings. Even when my boots were brand new, and also now that they have about 20 days on them, snapping them empty into the HHs the boot heels float about 1/2 inch over the heel blocks. Tightening the cables to increase pre-load on the springs seems to have no effect on the height the empty boot heels sit above the heel blocks. This amount of slack before the springs engage during forward flex is bound to reduce the amount of control, especially during lead change when control is critical. HH has no built in ramp angle in the toe piece to reduce this, but does have a 1/4 inch higher heel block than the main shim of the toe piece which may be an inexpensive design change to reduce some of the apparent rocker launch by putting the heel higher than the toe. I've planned all along to swap the HHs on my primary skis for Axls to get the free pivot for touring. I'm now thinking the 2 degree ramp angle built into the Axl toe piece should also make for less rocker launch and better control through the early flex. In addition, I believe Axl keeps the boot more level, with the heel block at the same height as the toe piece, though I have not been able to measure an Axl to confirm this.

    It would very be helpful to get some opinions on the possible skiing differences I might expect in changing from HHs to Axls based on these heel/toe height and ramp angle differences.

  • #2
    As you mentioned, a binding wedge had been an effective answer to counteract boot rocker on simpler tele-bindings. No simple solution for HH's or axls... When I skied "Riva II's", I used a pair of wedges and really liked how much it helped those simple bindings engage much earlier and get the skis to react quicker. (the effect you hope to duplicate)

    With HH's and Axl's, the greater the angle that your heel cable connects to your boot, the more that cable resistance will pull down on your heel (to counteract some boot rocker) AND will also promote earlier engagement of your binding's springs which will generate pressure to your ski tip more quickly. (which translates as a quicker reacting ski) You may not need more spring tension, and in fact you may lower the tension if you move the pivot pin backward to get earlier engagement AND the feeling that you prefer. (earlier engagement to help counteract the boot rocker)

    That's all I got given your parameters..... hth...
    the fall line is your friend.... resistance is futile

    Comment


    • #3
      Originally posted by tele.skier View Post
      As you mentioned, a binding wedge had been an effective answer to counteract boot rocker on simpler tele-bindings. No simple solution for HH's or axls... When I skied "Riva II's", I used a pair of wedges and really liked how much it helped those simple bindings engage much earlier and get the skis to react quicker. (the effect you hope to duplicate)

      With HH's and Axl's, the greater the angle that your heel cable connects to your boot, the more that cable resistance will pull down on your heel (to counteract some boot rocker) AND will also promote earlier engagement of your binding's springs which will generate pressure to your ski tip more quickly. (which translates as a quicker reacting ski) You may not need more spring tension, and in fact you may lower the tension if you move the pivot pin backward to get earlier engagement AND the feeling that you prefer. (earlier engagement to help counteract the boot rocker)

      That's all I got given your parameters..... hth...
      Thanks t.s, for those ideas.

      I do understand that moving the cable pivots further back increases the heel hold-down. That's why I have always skied my HHs in position 5, the rearmost. What troubles me is the way the boot heels, unloaded, just float above the heel blocks, and that is in the rearmost cable guide position on HH, and at any tightness of the cables. This indicates to me that there's at least that much of the arc of forward flex that is going to go by before the springs do anything. In fact, since the boots seek that floating position with the heels in the air, flexing them forward when skiing, the first half inch of heel lift is spring-assisted, not resisted, hence, no doubt, the term rocker launch.

      I think the main thing I would like to resolve is whether or not getting some Axls would be likely to improve the rocker launch situation, with their built in 2 degree ramp angle in the toe piece, where HH has none, and the fact that the heel support is the same height as the toe plate, instead of 1/4 inch higher than the toe plate in the HH. I don't want to spend my money on some Axls and find that except for the selectable free pivot feature, they still have the same slack area in their activity. And the Axls are heavier than the HHs, and have more mechanisms to fail.

      Also hoping to learn anything about how heel height compared to toe plate height affects skiing dynamics, since Axl holds the boot sole level, parallel to topsheet, where HH holds the boot sole heel-high.

      Your suggestion to try lowering the cable pre-load to see how it feels seems a good one and surely worth a try. That might at least reduce the spring-assisted part of the flex arc. If this seems better, it may be helpful to install the stiffy springs I already have for the HHs. Changing the springs is major surgery with HHs, which in my case involves removing the heavily epoxied-in-place bindings from the skis. It may be time to install some threaded inserts in the skis.

      Comment


      • #4
        First, rocker launch is not a function of bindings. It is a function of boots. Some boots start out rockered (T2s) and develop more the more you make tele turns. Others start out flat and develop some rocker over time. Some bindings mitigate rocker launch for the reasons you have described, but don't blame your bindings for the fact that your boots have rocker.

        Have you skied them yet? How much do you weigh? And what boots? If you have enough weight to keep your heels down with both feet weighted equally, it won't be much of a problem. But if you can't keep your heels down at all it will be a big problem.

        Comment


        • #5
          I never noticed any rocker launch with either Axls or HHs. I found them both equal performance wise, it was hard to tell the difference between the two.

          Comment


          • #6
            Originally posted by Hindfoot View Post
            I do understand that moving the cable pivots further back increases the heel hold-down. That's why I have always skied my HHs in position 5, the rearmost. What troubles me is the way the boot heels, unloaded, just float above the heel blocks, and that is in the rearmost cable guide position on HH, and at any tightness of the cables. This indicates to me that there's at least that much of the arc of forward flex that is going to go by before the springs do anything. In fact, since the boots seek that floating position with the heels in the air, flexing them forward when skiing, the first half inch of heel lift is spring-assisted, not resisted, hence, no doubt, the term rocker launch.
            Yeah, that's the dreaded "dead spot" where there's no feeling of early engagement with the bindings. The NTN freeride has that inherent in it's design since it doesn't have a rearward pivot point, but it doesn't bother me because I don't incorporate a lot of binding generated leverage in my technique. Rottefella thought binding leverage was an important enough "effect" to have incorporated a bit of wedge angle into the NTN freedom binding, so the early spring engagement is noticeable on the freedom's when I switch back and forth between the 2 bindings.

            Originally posted by Hindfoot View Post
            I think the main thing I would like to resolve is whether or not getting some Axls would be likely to improve the rocker launch situation, with their built in 2 degree ramp angle in the toe piece, where HH has none, and the fact that the heel support is the same height as the toe plate, instead of 1/4 inch higher than the toe plate in the HH. I don't want to spend my money on some Axls and find that except for the selectable free pivot feature, they still have the same slack area in their activity. And the Axls are heavier than the HHs, and have more mechanisms to fail.
            If what you say about the 2 degree ramp and lower heel height is true, I think your analysis is good and it will noticably improve your rocker launch,... but essentially rocker launch is a boot issue, so it probably won't completely disappear.

            Originally posted by Hindfoot View Post
            Also hoping to learn anything about how heel height compared to toe plate height affects skiing dynamics, since Axl holds the boot sole level, parallel to topsheet, where HH holds the boot sole heel-high.
            Well...... I have said this before and posted a stick figure that I found on the net with my explanation. The key element in a skier's posture is his shin angle.... IF a skier has a locked cuff, then his shin angle is determined by his heel/toe height relationship and the angle he locks his cuff at. (skiers like cesar, don't lock their cuff, so they can always adjust that shin angle by flexing their ankle ) Locked cuffs don't allow you to change the angle of your ankle so cuff lock angle and heel/toe height relationships are important if you want to maximize leverage and energy efficiency.

            ... my point in your case is that if you have your boot cuffs locked at the more forward lean angle, then you will have to drive into a deeper tele to engage the binding resistance. You can try locking your cuffs at the more upright angle and your binding springs will engage earlier. (but your new resting shin angle will be more verticle, and hopefully still workable for you)

            The potential problem with my suggestion is related to heel/toe height and the cuff lock angle giving you a too verticle shin angle and putting your hips in the back seat position. From the back seat you can't even pressure your boot cuffs. If you feel like you are leaning backward on your boot cuffs at full leg extension, your shin angle is too verticle.... so your binding may engage earlier but you aren't in your "stacked position" any longer and that is essential to ski well.... At that point you can either unlock your cuffs, lock them in a more forward cuff lock position or shim your heel up....

            here's that image to help you visualize... what I am babbling about...

            Click image for larger version

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            Originally posted by Hindfoot View Post
            Your suggestion to try lowering the cable pre-load to see how it feels seems a good one and surely worth a try. That might at least reduce the spring-assisted part of the flex arc. If this seems better, it may be helpful to install the stiffy springs I already have for the HHs. Changing the springs is major surgery with HHs, which in my case involves removing the heavily epoxied-in-place bindings from the skis. It may be time to install some threaded inserts in the skis.
            My suggestion was to move the pivot backward and lower the spring tension,... IF you only lower the tension without moving the pivot that will probably make your boot rocker even worse and the dead spot feel even bigger...


            Overall, I would go with the axls as your best option if the things you said about the axl's ramp angle are true. Try the more verticle cuff lock position on your boots on your current set up too, and be weary of whether it gives you that back seat feeling...

            *stiffy spring could also help too.
            the fall line is your friend.... resistance is futile

            Comment


            • #7
              http://www.bishopbindings.com/

              Toe Bail System

              A Toe Bail offers big benefits over the traditional fixed toe box design of almost every other telemark binding out there.


              Consistent performance. The Toe Bail does not rely on the traditional pinch or squeeze method required to hold a telemark boot into a fixed toe box as found on other bindings. As the boot wears down it will perform differently in a fixed toe box resulting in inconsistent performance. The Toe Bail also allows for easy exit and entry from the binding, as it does not bite into the duck bill of the boot like a fixed toe box which equals less wear and tear on the boot.

              Eliminating Rocker Launch. "Rocker Launch" is a name that has been given to an unwanted effect when the heel of your tele boot is spring loaded away from the ski. Notice the tele skier on the lift in front of you with some other tele bindings - skis flobbing around off the boot heels. Not cool. This happens when the flexing bellows near the toe develop a permanent flex to them over time. We also call this the "Elf Toe" effect. You can see this as a gap at the toe of your boot when your foot is flat on the ground. This can give you the sensation of being launched over the front of the ski. Thus the name "Rocker Launch".

              The Bishop is designed with a pivoting Toe Bail and a small amount of downward clamping force on the heel of your boot that eliminates Rocker Launch and keeps your skis firmly against the heel of your boot even when you are launching huge air = badassery.

              Comment


              • #8
                ^^^ this ^^^

                Comment


                • #9
                  Originally posted by tele.skier View Post
                  Yeah, that's the dreaded "dead spot" where there's no feeling of early engagement with the bindings. The NTN freeride has that inherent in it's design since it doesn't have a rearward pivot point, but it doesn't bother me because I don't incorporate a lot of binding generated leverage in my technique. Rottefella thought binding leverage was an important enough "effect" to have incorporated a bit of wedge angle into the NTN freedom binding, so the early spring engagement is noticeable on the freedom's when I switch back and forth between the 2 bindings.
                  Originally posted by tele.skier View Post


                  If what you say about the 2 degree ramp and lower heel height is true, I think your analysis is good and it will noticably improve your rocker launch,... but essentially rocker launch is a boot issue, so it probably won't completely disappear.

                  Originally posted by tele.skier View Post






                  Thanks, t.s, for the amazingly comprehensive analysis of this situation. Yes, it's the boots that are causing it, but not because they are old. They have done it since new, to the same degree. I have about 20 days on them so far, and don't think it is going to get a lot worse, but who knows.










                  Well...... I have said this before and posted a stick figure that I found on the net with my explanation. The key element in a skier's posture is his shin angle.... IF a skier has a locked cuff, then his shin angle is determined by his heel/toe height relationship and the angle he locks his cuff at. (skiers like cesar, don't lock their cuff, so they can always adjust that shin angle by flexing their ankle ) Locked cuffs don't allow you to change the angle of your ankle so cuff lock angle and heel/toe height relationships are important if you want to maximize leverage and energy efficiency.

                  ... my point in your case is that if you have your boot cuffs locked at the more forward lean angle, then you will have to drive into a deeper tele to engage the binding resistance. You can try locking your cuffs at the more upright angle and your binding springs will engage earlier. (but your new resting shin angle will be more verticle, and hopefully still workable for you)

                  The potential problem with my suggestion is related to heel/toe height and the cuff lock angle giving you a too verticle shin angle and putting your hips in the back seat position. From the back seat you can't even pressure your boot cuffs. If you feel like you are leaning backward on your boot cuffs at full leg extension, your shin angle is too verticle.... so your binding may engage earlier but you aren't in your "stacked position" any longer and that is essential to ski well.... At that point you can either unlock your cuffs, lock them in a more forward cuff lock position or shim your heel up....

                  here's that image to help you visualize... what I am babbling about...


                  [ATTACH=CONFIG]2800[/ATTACH]








                  This is something I had not even considered and a great explanation of the whole issue. My boots, Garmont Voodoos, have only a single angle cuff lock, which seems quite vertical to me. I have to work at keeping my knee forward enough and it's always pretty much up against the limit of the cuff lock when it is, though I never feel like I am putting pressure onto the back of the cuff. I can see how lowering my heel would exacerbate this already pretty vertical cuff angle, putting me into the back seat, possibly. I have skied these boots with the cuffs unlocked, but have tried not to do that, thinking I might be limiting my ability to pressure my back foot. But I can see that the shin angle is more important than I realized. Your explanation makes this very clear. If I do get the Axls and this becomes a problem, a possible solution might be to drill another hole in the cuff lock bar to allow a more forward position to be locked in, providing there is room enough on the sliding bar to put another hole that will not be too close to the original one. Don't want too much lean in the cuff angle. Modifying Garmont gear could be risky, since there is probably little chance of getting any replacement parts if one screws something up. Or I could shim the heel up as you suggest.

                  My suggestion was to move the pivot backward and lower the spring tension,... IF you only lower the tension without moving the pivot that will probably make your boot rocker even worse and the dead spot feel even bigger...


                  That's a good suggestion except the pivots are as far back as they will go. I really like the solid activity of the HH bindings and from the start have always had them on the stiffest setting, position 5, all the way back. With size 29 boots I am not feeling the stiffness of someone with smaller boots, so I bought some stiffy springs for them, which I have not yet installed to try. I've been on Hammerheads for 3 years but wanted to try my new-this-year Liberty Helix skis with the HHs with the standard springs before installing the stiffies. Pathetically, only six days so far this year due to the lousy snow situation. But, I will try lowering the pre-load tension of the cables and see how they feel.









                  Overall, I would go with the axls as your best option if the things you said about the axl's ramp angle are true. Try the more verticle cuff lock position on your boots on your current set up too, and be weary of whether it gives you that back seat feeling...

                  *stiffy spring could also help too.
                  I expect that getting the Axls is what I will do, sooner or later. Would like to try the stiffies on the HHs, just to see what the difference they might make with this situation. If they improve things, I can order stiffies for the Axls, and with them one does not need to dismount the whole damn binding to change the springs. That alone might be enough reason to upgrade.

                  Thanks again taking the time to post such a detailed and solid analysis.

                  I see that the posted version of this is messed up, with responses mixed in with quotes, but I don't know how to fix it, nor do I have time right now.
                  Last edited by Hindfoot; 26 April 2014, 10:19 PM.

                  Comment


                  • #10
                    I skied Bishop bombers for many years, They Do eliminate the rocker launch, but they DON'T eliminate the dead spot associated with rockered boots, so buying bishops would not make your boots engage the springs earlier than any other binding. Bishops just don't pull down on the duckbill to create rocker launch like the rest of the duckbill bindings with "toe boxes" do.

                    I am pretty aware of the bishop's flaws and posted a redesigned bishop as a hoax on TTips a few years ago (with Fin's full knowlege btw) It got some funny comments. I pmed Hdiddy and told him it was a just a hoax.... Anyone remember this?

                    Click image for larger version

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                    I added a height adjustable, pivoting toe stop to eliminate ' boot rocker caused' delayed spring engagement, and create a tour mode. I also added a center plunger to actuate a ski brake. I never designed a release.... I had also envisioned having multiple toe bails of different lengths to be able to move the boot forward or backward to change the binding's activity similarly to moving a pivot pin on HH's... Bishops were never similarly active for boots of different sizes, They were more active if you had small feet.... and not so active if you have size 13...

                    As much as I liked bishops because I like a moderately neutral binding, I would never recommend them to someone who skis HH's on 5..

                    The bishop has so much potential. It's a shame that it re-emerged in it's original unimproved form...
                    the fall line is your friend.... resistance is futile

                    Comment


                    • #11
                      It'd be great to know what boot you are on, and whether it is prone to rocker or has a curve inherent in its design like the T2 or some of the older Garmont's. With my T1's with the flat sole, I never experienced your issue, even with boots over 200 days of use. As with Repete, I could go interchangeably from AXL's to HH with no issues and no real transition. I skied HH3 and AXL2, as I don't like an overly active binding, just a nice solid "middle of the road" feel.

                      Even in the most worn boots, perhaps there was a bit of unweighted lift, but once in the boot and in the binding with human weight added, I can't really imagine how this would be a noticeable condition unless the boot has so much rocker launch that you are working to counter it. Then, as noted, it's the boot, not the binding.

                      I've noticed the dead spot on the Freeride since I got them about 8 days of skiing ago, and it's a bit more than AXL or HH for sure. However, again, this is something noticeable in the shop or a bit when standing at the trailhead, but is completely irrelevant when skiing the binding. I appreciate a small bit of this deadness, rather than instant engagement, as I feel it makes the binding transition quicker, especially in moguls or choppy conditions, where you want to turn quickly. You spend less time trying to break the binding resistance and more time breaking the bellows, and engaging the ball of foot and ski. I guess that's why I never could get why HH5 and AXL3 exist for my preferences.

                      Comment


                      • #12
                        I've skied Bishops, Axls, HH's (even tried stiffy springs) and now Freerides. I'm not a big guy, skiing T1s and now TX Pros. I think there's much more variables in boots than between the bindings mentioned, if the boots are the issue switching bindings will not solve the problem. The real benefit for me to switch to NTN is the TX Pros fit my feet much better than the T1s, otherwise I actually find all the setups ski similarly. FWIW I do find greater control with the Freerides than with 75mm.

                        Comment


                        • #13
                          WH, thanks for the earnest observations. My boots are Garmont Voodoos. I suspect they may have an inherent curve in the sole since they never sat on the heel blocks in the bindings when empty even when new. They certainly sit down on the heel blocks when I am in them, and I can't say that I can feel the rocker launch when skiing. It's just that seeing that slack where the springs aren't doing anything makes me realize that there has to be a part of the flex arc that may be wasted motion and it seemed like a good idea to try to reduce that as much as possible. Was hoping getting some Axls might be a solution, while making touring more efficient.

                          In this low snow year I spend lots more time thinking about tele turns that I have opportunities to actually make them since I currently have to do long distance driving to get to any snow. Your grounded comments from experience on both Axls and HHs makes me think I may be making too much of my observing that the heels of my boots are up in the air when the boots are in the bindings but I'm not in them.

                          The explanation by tele.skier about how a binding that lowers the boot heel as Axl does relative to HH, which in a boot with a more vertical cuff lock can change the shin angle enough to put the skier in the back seat, is starting to raise a concern I hadn't thought of with transition from HH to Axl. I am concerned that may be the case with these Voodoos, which have only one non adjustable cuff lock position and it is pretty vertical. Did you notice any need to adjust the cuff lock or change your stance when going between HH and Axl?

                          Comment


                          • #14
                            Originally posted by repete View Post
                            I've skied Bishops, Axls, HH's (even tried stiffy springs) and now Freerides. I'm not a big guy, skiing T1s and now TX Pros. I think there's much more variables in boots than between the bindings mentioned, if the boots are the issue switching bindings will not solve the problem. The real benefit for me to switch to NTN is the TX Pros fit my feet much better than the T1s, otherwise I actually find all the setups ski similarly. FWIW I do find greater control with the Freerides than with 75mm.
                            Thanks for the comments, repete. It was probably all the comments this year about how much more control NTN has over 75mm bindings that got me to looking closely at my HHs to see if I could improve the control I am getting from them, which led to my initial request for opinions. I wouldn't be surprised if I were to end up with NTN, but can't afford to switch for a while with such new boots and bincings. If I decide to spring for the Axls, that would extend that time.

                            Did you notice any changes in your stance or need to adjust your cuff lock in switching between HH and Axl? tele.skier's comments on this thread about this make me wonder.

                            Comment


                            • #15
                              .... too further elaborate, I experienced this exact issue of too verticle of a shin angle when I purchased the NTN freedom binding which has a built in wedge angle to promote early spring engagement. I supose rottefella thought early engagement was the simplest way to make their binding feel more powerful because their design doesn't lend itself to the movable pivot pin solution which was the genius of HH's.

                              .... I have 2 cuff lock positions on my boots. I prefer the more verticle position when I used the "freeride's" because at full leg extension I have very little knee bend which translates into a stance with the greatest energy efficiency. When I put that same boot in the "freedom" binding, I fell down 3 times in the first 100 feet. The change in the ramp angle was enough to make my shin angle too verticle and put my hips slightly in the back seat. At full leg extension, I was out of balance. (hips in the back seat)....

                              I could do 1 of 2 things. I could use the more forward leaning cuff lock angle on my boots and accept a slightly less efficient resting position with a little more knee bend, OR I could experiment with shim thicknesses for the heel of the "freedom" binding and dial in the shin angle I prefered on the "freeride" binding.

                              I made the shims in 1/8th and 3/16th thicknesses out of clear polycarbonate and chose the 3/16th thickness after trying both. The shim allowed me to use the more verticle cuff lock position that I prefer. I made a pair for a local ski buddy and he also prefers the taller cuff lock postion and shims to the more forward cuff lock without the shims...

                              Click image for larger version

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                              All of this is micro adjusting is done only to maximize energy efficiency. Certainly, most people would just use the more forward cuff lock angle and be done with it.... Hindfoot, you can shim your binding heel too if your shin angle is too verticle due to the ramp angle of the Axl binding.... when the time comes...

                              binding ramp angle and boot cuff lock angle determin a skier's shin angle. You can always shim the heel if your cuff lock angle is too verticle.... simple fix...
                              the fall line is your friend.... resistance is futile

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