lateral stiffness of bindings

[theorist]

Lateral deflection of the binding when the ski is on-edge reduces its angulation, and some bindings deflect more readily than others. But how significant is this in actual skiing?

If you click your boot (not while wearing it) into a binding, and then anchor the ski so it doesn't move (say, put the ski on the kitchen floor and straddle the binding), you'll notice two things: (1) it's relatively easy to rock the boot laterally, by at least a few degrees; and (2) some bindings clearly resist this rocking better than others. I don't know how this translates into the kind of forces a ski experiences when it's up on edge, but it seems plausible this lateral compliance could result in a few degrees of angle loss (equivalent to canting in the soft direction) at the apex. This seems like it would be significant.

As a practical matter, I just acquired a pair of Supershape KERS and am trying to decide between an FF14 and an FF16. A contact at Head reports that the FF16 shows less lateral deflection than the 14 because of a stiffer housing (I've not confirmed this personally), but that the FF14 has the potential safety advantage of the diagonal heel and full-diagonal toe.

[Max_501]

Harald has no problem putting his hip 1" from the snow with the FF14 bindings. I certainly haven't noticed any lateral deflection in any of my bindings so IMO it is insignificant for most skiers. Perhaps at the WC level this would be an area for fine tuning.

[theorist]

Thanks. I'd asked b/c I was wondering if more compensation (extra-aggressive eversion of the stance foot near the turn apex) would be required to maintain edge hold on ice with some bindings than others, but it sounds like that's not the case for recreational skiing, and the FF14 does the job.

BTW, I assume you're referring to retail bindings -- my Supershapes are new, but came with SP12 demo bindings (installed on the standard SP13 plate), and these should be swapped out because of lateral slop, right? [Also, the SP12 gives me an extra 11 mm of stand height over the FF14, which I've been told is too much.]

May I ask how much toe lift (if any) you and Harald use on your FF14's? One manufacturer told me that, with lots of toe lift, the boot-binding interface loses lateral stiffness because the boot is significantly out of its design ramp angle. Unless I gas-pedal my boots, I'd need 6 mm with the FF14 and 4 mm with the FF16. But if you guys also use significant toe lift, that would indicate this is not a concern.

Say, would anyone happen to know the range of toe lifter kit sizes available from Head for the Freeflex?

[Max_501]

Have you tried the demo bindings yet? I've got them on a couple pairs of skis and haven't had an issue.

[theorist]

Not yet, tomorrow will be my first day on them (local conditions finally good enough to not need rock skis). Will report back.

[CO_Steve]

BTW, those FF16 bindings weigh a ton.

[theorist]

I wouldn't sacrifice performance for weight but, everything else being equal, lighter is better. I don't notice ski weight when skiing, but hanging weight on the lift is important -- in the absence of a footrest, heavy systems can stress my knees. Lighter is also nice for climbing.

As to the actual weights, the FF16 (as opposed to the FF16X) is pretty close to the demo binding, though it is 370 g/pair (6.5 ounces/side) heavier than the FF14:

[Weights are per pair, from the '14-'15 Tyrolia tech manuals]
SP12 (DEMO): 2600 g
FF Pro 11: 2290 g
FF Pro 14: 2330 g
FF Pro 16: 2700 g
FF Pro 16X RD, 18X, 20X: 3020-3050 g

A bit OT, but since we're talking weight: I don't have one available to measure, but if typical mondo 26 plug boots are 4800 g/pr., then the Dodges, at 3400 g/pr. with a race liner, are 1400 g/pr. lighter. So one can put the weight savings of the Dodges in perspective by noting it's twice the difference between an FF14 and a full-on metal race binding like the FF20X.

[Max_501]

What's great is that none of that matters when it comes to making the perfect PMTS turn!

[theorist]

So I skied them yesterday and the performance was remarkable, from which I infer the bindings were fine. I'll need to revisit this, but they seemed a bit easier to tip than my Mya 7's -- could the extra 11 mm of stand height be having an effect?

The demo bindings move in 8 mm increments, and my initial preference is for -3 mm (3 mm aft) over +5 mm. If I were to put on a FF binding, I'd be at +3 mm (assuming Head has calibrated the sole length numbers consistently on the SP12 demo binding and the SP13 plate). So the choice of binding comes down to whether I think the FF14's diagonal heel would be safer, whether or not I like the extra cm of stand height during all-mountain skiing, my preference for fore-aft position, and whether I want to spend the extra $$. I'll stick with the demo binding for now.

[Max_501]

...could the extra 11 mm of stand height be having an effect?

Yes. That's why I never mount flat, even on my fat off piste skis.

[krazzy legs]

theorist
Head does make very good skis. Knee binding I think makes the safest binding. With my head isl I removed the plate the binding sat on & replaced the head bindings with knee bindings. I really like the way knee bindings ski, From knee binding I put a plate under toe so heal & toe are the same height.

[theorist]

theorist
Head does make very good skis. Knee binding I think makes the safest binding. With my head isl I removed the plate the binding sat on & replaced the head bindings with knee bindings. I really like the way knee bindings ski, From knee binding I put a plate under toe so heal & toe are the same height.

I have a couple of pairs of KneeBindings, and could pull one off and put it on my Supershapes. But a contact at Head told me that the Speedplate 13 contributes significantly to the Supershape's performance, so I'm not willing to remove the plate, which would be needed to install the KneeBindings. [I don't believe you can mount the KB's onto the plate, because it's mostly hollow and only reinforced to hold screws at the existing holes.]

[theorist]

...could the extra 11 mm of stand height be having an effect?

Yes. That's why I never mount flat, even on my fat off piste skis.

How high are you going? If it's just the standard plated height of 3 cm (e.g., FF14 on SP13 plate), have you ever found a downside to being beyond this, like I currently am (4 cm), for powder or moguls?

Given the tipping advantage extra-high bindings provide, has HSS ever considered using them as learning tools during camps? An alternative approach, for students that have trouble sensing whether or not they are tipping during skiing, might be to put them on very wide (~120 mm) skis and have them try to tip those (just for a run or two). Sort of like resistance training for tipping. This would provide strong and immediate proprioreceptive feedback to their lower legs telling them whether they were tipping. The danger, though, would be that this requires so much effort that they might be using their knees in addition to their ankles.

[krazzy legs]

theorist

The knee binding does allow the ski to flex under foot so I do not think it would effect performance. For an experiment try bending a ski with a knee binding & a ski with a plate with head binding both with & without a boot & compare how the ski flexes.

[theorist]

theorist

The knee binding does allow the ski to flex under foot so I do not think it would effect performance. For an experiment try bending a ski with a knee binding & a ski with a plate with head binding both with & without a boot & compare how the ski flexes.

I don't believe hand-flexing would be definitive; to do the test properly you'd need to have identical pairs mounted with a KB and a plate and ski both, switching back and forth. Alternately, if you were very familiar with the ski, I suppose you could redrill it for the KB and see if it feels different. But since the ski is new that's not an experiment I'm willing to undertake at this time!

Sure, it's possible I might not notice a difference. But I've been told the SP13 plate is an important part of the designed performance of the iSS and, in particular, that the plate offers higher performance on groomers than one would get if one replaced it with a PRD system (the latter is biased towards allowing the ski to flex), from which I infer the plate adds some stiffness underfoot. [Yes, the iSS Speed has the PRD, but it's designed for that binding, and likely there's plenty of stiffness underfoot built into the ski itself.]