Xplore vs. 3pin+cables

[fisheater]

While I think that a heel "cable" can improve the lateral stability of a boot sole- my limited experience is that this is very limited. A soft flexible, unstable boot sole stays unstable wrapped in a heel cable- I have had soft unstable soles twist- and even pop out- of a heel cable.

My personal limited experience is that the primary downhill advantage of clipping on the heel cable to a soft Nordic touring boot are:
1) power transfer→ the resistance of the heel cable transfers force from the rasied-heel down into the ski- making it easier to pressure the trailing ski into a turn.

2) fore-aft stability→ if you haven't had the "over-the-handle-bars" experience of downhill skiing in the backcountry with a completely free heel- don't know what to say...the heel cable stops me from "going over the handle bars" when I hit uneven/irregular conditions when downhill skiing on backcountry snow/microtopography.

And finally- within certain limits- increasing resistance in a toe flexor can and does produce the same results as 1&2 above. This true with NNNBC- I am certain it is true with Xplore- hence the stiffer downhill flexor.
............
My current two cents on this-
The Alfa Free boot is in the "Extreme" class (e.g. Asolo Extreme/Crispi Svartisen/Fischer Transnordic) of boots- not the "Excursion" class (e.g. Garmont Excursion/Scarpa T4).
The Xplore binding takes the "Extreme" class to the next level, due to the rigidity of the boot-binding interface- this will make the power transfer of the Free/Transnordic/Svaristen XP more effective than on NNNBC or 3pin.

Will the stiffer downhill flexor in the Xpore binding give one the same performance that I speak of in #1&2 above? Don't know yet...

In the end I may still mount the Rotte ST+cable on my Rabb 68. Why?
Because:
1) I already have the binding- and I- AMAZINGLY- can buy this binding for 50% of the $$$ as an Xplore binding + downhill flexor.
2) I have a number of 3pin boots that I love- including the Scarpa T4.
3) I think I would rather clip on a heel cable than frig with that ridiculous flexor plate system on Xplore that I DAMN well know will FREEZE in my local environmental context...

Not in a rush to put Xplore on my touring for turns skis...

Gareth, I always thought the primary reason of the cable was primarily to transfer the power from the raised heel to the ski, and to assist the skier in getting the BoF onto the ski with a stiffer boot. Especially with newer plastic boots.
I understand your point two about going over the bars. However as a beginning skier I was a back seater. I learned the error of those ways, I am a confirmed stand on top my skis guy. I am now the still occasional go over the bars guy. That probably would happen with very active bindings, but I don’t ski that type of binding and stiff plastic boot.
Now onto my more important point. I view the Alaska 75 as a fairly soft soled boot. What makes the Rotte ST cable unique is that it makes that laterally (and most other directions) floppy sole stiff and reliable.
Since you own a Rotte ST cable, pull it out of the box and hook those cables up. It’s kind of a PITA, isn’t it? However holding the binding secure try to move that cable laterally from the heel piece. You’ll find very little movement at all. Of course the Voile 3-pin cable moves all over as would a Targa type cable. Even the 3 pin Hardwire type cable doesn’t compare to the lateral stiffness of that Rotte cable.
That is why I believe even a floppy boot like the Alaska 75 can become such a powerful boot in that Rotte ST cable.
In full disclosure, I hated that cable when it first arrived. I carried in my pack in a lot of situations when I should have been using it. Only when my skiing embarrassed me, did I pull it out. I went immediately from not being able to control my inside ski as I expected, to skiing exactly as I expected. I was skiing on the road, I thought I was going back to a motel room to get a different boot.

[fisheater]

Again @GrimSurfer The pivot point the binding is the fulcrum. The compression of the spring assists the bellows to compress keeping the BoF flat on the boot. In active bindings it most definitely does allow the skier to pressure the front of the ski, just as any alpine skier knows that their fixed heel allows them to pressure the front of the skis. It is also why it’s so easy to go over the bars without a cable or a very neutral binding. It’s also why Volle doesn’t warranty certain skis with Telemark bindings. The forces from a raised and restrained heel pressure the front of the ski.

[GrimSurfer]

Again @GrimSurfer The pivot point the binding is the fulcrum. The compression of the spring assists the bellows to compress keeping the BoF flat on the boot. In active bindings it most definitely does allow the skier to pressure the front of the ski, just as any alpine skier knows that their fixed heel allows them to pressure the front of the skis. It is also why it’s so easy to go over the bars without a cable or a very neutral binding. It’s also why Volle doesn’t warranty certain skis with Telemark bindings. The forces from a raised and restrained heel pressure the front of the ski.

It positions the foot. The foot transmits the force. Not the cables… those forces balance to ZERO.

This is elementary school physics. Full stop.

[GrimSurfer]

Here’s a way to confirm Newton’s Third LAW of motion…

Remove a NN/3 Pin binding from a ski. Lock the bail onto a ski boot duckbill. Hook on cables and place them over the heel of the boot. Put the boot down on a flat surface.

Does the boot move forward on its own? Of course not. That would be impossible.

The duckbill is locked to the 3 pin binding. The force exerted by the cables on the back of the boot are equal and opposite to the forces pushing from the other direction through the duckbill.

None of this is transmitting force in one direction. It might be compressing the sole of the boot somewhat. But that compression is happening in both directions. They cancel out.

There are likely all kinds of BS artistes selling higher tension cables, claiming these are improving drive. What they’re actually doing is placing greater force on the boot to overcome skier limitations in foot control. They don’t impart any force on the ski. Only the skier can do that.

This is a skier aid which makes up for limitations in ankle control. It is not a device that transmits force in any single direction. Whatever forces are imparted on the boot, and only the boot, are equal and opposite.

[wabene]

Why would people want to ditch the cables for k & g on the flats if there wasn't resistance to lifting your heal? What is the purpose of springs if there isn't resistance provided? Since the pin line and cable attachment are offset, there are two separate fulcrums that operate on different axes. That is why when you lift your heal, resistance is created resulting in the opposing force pressuring the tip. At least that's what makes sense to me. The axis of the cable is closer to the ball of foot aiding in flexing that part of the boot.

[GrimSurfer]

Because all of this is about foot control, not the driving forces on the ski. That’s the job of the foot and weight transfer of the skier.

It is important for this to be understood. Otherwise,not leads to all kinds of erroneous nonsense.

The duckbill is actually locked in place. It’s not going anywhere. The foot and weight of the skier are providing the drive. The cable is a control element for the foot… that control element could just as easily by the longitudinal and torsional stiffness of the boot.

If you have a floppy boot and floppy ankles, cables may help. But they only help position the boot. They don’t transmit force onto the ski. That’s the foot’s job.

[wabene]

When you lift your heal more force is applied to the front of the ski. This will not happen without your foot moving, but it certainly is the cable applying the extra force. Every conversation doesn't have to lead to some kind of theoretical blabbering.

[fisheater]

Only so others can understand. You may have studied more physics, but the cable (spring) restrains the heel and captures the energy of the heel being raised against the pivot and being restrained by the cable (spring)
Many very good heavier Telemark (high plastic boot) skiers prefer a more neutral binding (less spring) because with shorter, stiffer, downhill oriented skis an active binding can make it easier to stick a tip.
Experienced downhill skiers understand pressuring the front of the ski. It’s easier to do with a fixed heel, just pressure the shin to the boot. It is very difficult with a soft boot and a 3-pin binding, all you have is the ball of you foot and toes to pressure the ski. While not a fixed heel, a spring attached to a fixed point allows you to lever the front of the ski.
Anyone that can downhill Telemark well, and has skied a stiff plastic boot and Hammerheads on #5 understand it’s a lever and not the pressure of your foot.
Maybe @GrimSurfer you just never experienced these dynamics and just don’t understand. Attaching the heel with a spring to a pivot definitely creates a lever whether or not you can understand the physics. Detach the heel, the lever is gone.

[fisheater]

Skiing is 3D even on hard snow. Place the ski on a bed of jello, lift the heel and the front of the ski goes down in the jello.

I’m out, I understand skiing and I’ve had enough

[GrimSurfer]

A fulcrum the the point around which forces *rotate*. The term rotation implies *movement*.

The bindings don’t move. They’re firmly attached to the ski. So where is the fulcrum?

Spot the fulcrum in the photos below. The cracking is happening because of flex. What is flex? Movement around a rotational axis.

Why is this happening in the same place? Because the duckbills are locked in the same place. Because weight transfer is through the sole of the boot. Because that transfer occurs along the same rotational axis.

The fulcrum is the sole of the boot. It’s exact location is between the portion of the duckbill that is locked to the binding and the ball of the foot.

Cables don’t change any of this. They simply assist in heel location. Forces get transmitted from the foot, to the boot, to the binding, to the ski.

People think I’m talking about them, questioning their ability. The truth is that nobody has infinite ankle strength or perfect muscular control. Nobody.

This isn’t about you or how you ski. This is about how things work in accordance with the laws of physics (which may or may not agree with how you’ve been used to thinking about them). It’s not my opinion. It’s physics… and I’ve provided ample examples and even photos that explain why we’re seeing fatigue cracking in the same location in boots worn by two different skiers.