Physics debate

[fisheater]

The binding is not a closed system. One end of the spring is attached to the a movable boot which compresses the spring. The other end of the binding is attached to the SKI.

The system isn’t closed.

Yes, flexors do the same thing. The flexor is also attached to the ski.

[TallGrass]

Interesting looking at this video at 2:25 and 4:25 (looks like the heel clip is off). You can see the cable-wire sweep against the side of the boot and the grey witness marks from it up and behind the cable attachment pivot.

Hard to see extension of silver to the front of the blue cartridge to the degree when clipping in

[1.]The cable is the element of the binding system under tension. [2.] That tension is created by the energy stored in the springs. Agree or disagree? Remember, we’re only talking about the cable at the moment…

1. Strictly speaking, disagree; it is 'a' element under tension. 2. "Created" or the result? Of an action+reaction pairing?

DISCLAIMER: I have seen various types of bindings shown, and while it does little good to throw in another type (another variable) which can lead to two people mistakenly thinking they are talking about the same one when they are not, I'll note the two types I currently use below. full size image


Edit: YT gif correction

[GrimSurfer]

The reasons why none of this is making any sense to people is two fold:

1. People don’t understand physics and
2. Everyone is trying to reach conclusions in one shot.

I’ve spent 120+ posts trying to explain things to people. I’m not going to continue on this path.

So if you (Tallgrass) wish any further commentary from me, let’s go through this one step at at time… saving our summations and conclusions until the end.

Crazy is doing the same thing over and over while expecting a different outcome. I’m off the crazy train… it doesn’t go anywhere other than to the same point in time where people tuned out of (or flunked) elementary school physics.

[TallGrass]

The reasons why none of this is making any sense to people is two fold:

1. People don’t understand physics and
2. Everyone is trying to reach conclusions in one shot.

I’ve spent 120+ posts trying to explain things to people. I’m not going to continue on this path.

So if you (TallGrass) wish any further commentary from me, let’s go through this one step at at time… saving our summations and conclusions until the end.

Crazy is doing the same thing over and over while expecting a different outcome. I’m off the crazy train… it doesn’t go anywhere other than to the same point in time where people tuned out of (or flunked) elementary school physics.

I (personally) would not say "people don't understand physics", rather some cause-effect relationships are easy, some challenging, and some quite complex. Having taught, it can take some longer to get certain things, and or different methods.

It's been said Science is the synthesis of Rationalism (explaining; abstract) and Empiricism (objective measurement; real world). I did fine in both high school and Uni' physics. I also like experiments as the way to distinguish between competing Rationalisms/Ideas/Hypotheses.

I also just took a tailor's measuring tape (e.g. for measuring one's waist), fixed end to a boot heel, measured to toe tip along the bottom of the sole, flexed it's fore-foot 90-degrees, and got a length 10mm longer. No, I didn't have my foot in it, but it jives with other squeaks and wear patterns I've had with footwear.

And the difference a cable's pivot point makes starts at 4:40, and I think I can make out the spring around the heel elongating (gaps between coils), fwiw.


So we can talk through things one-step-at-a-time, and that's Rational, and make conclusions based off that.
Yet if the conclusions do not mirror reality (Empirical), then something is off or unaccounted for.
Neither R nor E can exist in isolation and still be S.

I got similar results on my BD-cables on the Fischers as shown in the above video, alas they are not handy to play with presently.

I do not have the time/desire to (re-)read through X pages of verbal argument sans diagrams, consistent reference points, consistent equipment (i.e. boot, binding type, etc.), consistent term use, etc. That is why I prefer an article that uses words and illustrations that can stand on it's own without reader interaction, and why it is likely more constructive laying it all out in one go than to asynchronously incremental back-forth-back-forth-... (via a non-live-chat medium). We all have our own communication preferences, strong/weak points, as does each means of communication.

If you, GS, would like to PM me an/your article or specific links, in the last 40+ pages or elsewhere on the WWW, I'm open to it. I'll leave it to you whether to post it to the thread, and appreciate the time you've taken to reply to date.

Edit:
As far as cables, tension vs. compression, and vectors...

Simply saying a spring is under "tension" or "compression" is meaningless unless you know BOTH how it is set up AND the direction. As shown here, the direction is the same (blue and purple arrows), but the set up determines what is going on. Springs around the heel can work like the top, whereas those on the side, under the sole, or in front (hammerheads) could be either depending on design.




From https://earnyourturns.com/34754/diy-2-pin-tele-use-the-force-luke/




From https://earnyourturns.com/34324/diy-2-pin-tele-fixing-the-cable-position/


^ more effort than I'm up to.

[GrimSurfer]

Sounds good. I’ll take a 24 hour pause (125+ posts now has gotten in the way of my usual slothful retirement routine of eat until sleepy, sleep until hungry), and get back to you via PM.

This will likely be my last post on this thread because, frankly, I’m happy to leave people believing in whatever they really want. Even if that includes the magical properties of crystals, the infallibility of the zodiac, or the limitless power of cables.

[Stephen]

I haven't read all the latest, so forgive me if this is redundant.

It seems that @GrimSurfer assumes that the cable of a NN 75mm binding attaches at a certain spot or point in the binding system (this assumption is important, below).

Simplistically, there are three types of bindings:
Type 1: Free pivot (free heel);
Type 2: Alpine (locked heel);
Type 3: Something in between the above two.

I think @GrimSurfer assumes that a 75mm binding with a cable is essentially a Type 1 binding. And that the cable does nothing in the up/down plain, but does add lateral stability to the binding system.
If this is the case, his points make perfect sense -- they are true based on that assumption.

I think what most others are saying is that a 75mm binding + cable (part of the Post title this Post thread evolved from), that a 75mm binding + cable is a Type 2 binding, because the cable attaches to the binding system behind the natural pivot point of the boot.
Because of this, the binding cable creates resistance to raising the heel, which creates a rotational force centered around the toe of the binding, with the result that everything in front of the binding is pressed down with a force equal to the force required to raise the heel of the boot.

Yes or No?

[DG99]

I’m not entirely sure what’s going on here, but it seems like Stephen got it. All this stuff about everyone is stupidly thinking the laws of physics can be violated is confusing though!

[DG99]

Here’s that video again. The first bit is with the free pivot. The toe plate isn’t clamped down on the Switchbacks so it’s basically a hinge, you can go all the way forward, with no resistance. In that case, the ski tip isn’t really pressured.

The second part is with the binding toe plate clamped down. Then, there is a fair amount of resistance, so you can transmit force towards the ski tip. What might be throwing some people is that the cable is both pulling your boot into the toe plate (same as with the free pivot case), but also pulling downward because of the rearward attachment point. There is also a bit of camming action with the duckbill in the toe plate. I tried to show the springs and spring cartridge lengthening as the heel raises at the end, but it’s not really zoomed in enough.

You might look also at the Voile web site; these are the regular Switchbacks but they have the Switchbacks x2 with a more rearward attachment point for the cables which gets you more resistance, hence more tip pressure sooner. Another clue!

[TheMusher]

The reasons why none of this is making any sense to people is two fold:

1. People don’t understand physics and
2. Everyone is trying to reach conclusions in one shot.

I’ve spent 120+ posts trying to explain things to people. I’m not going to continue on this path.

As if you understand physics Think it’s abundantly clear you don’t, at this point.

[TheMusher]

When you pull on the back of the cable, it pulls on the binding. If the binding can’t move, the cable is actually pulling on itself (at the point where the cable attaches to the binding.

This is called “tension”. Clear?

Hint: So what is the direction of the normal force, i.e. counter force? With and without the cable in tension?