Physics debate

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DG99
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Re: Physics debate

Post by DG99 » Fri Jan 20, 2023 2:50 am

DG99 wrote:
Thu Jan 19, 2023 10:45 pm
This particular case seems like it might not have any downward heel retention force. Since, the cable pivot point is forward of the boot bellows where it’s bending, and the front part of the boot is being held down to the ski, the bellows is very soft and the cable isn’t too tight. Not sure though, but would be easy to know if you had it on your foot!
When I put soft leather boots in a hardwire cable it crushed my foot, painfully.
Answering my own question here….

I stuck a very soft XC boot in the Switchbacks, sort of like that GIF pic system. It is very “neutral” as the boot just crushes down at the bellows, above the toes, and the pivot point on these bindings is fairly far forward. There really isn’t much downward pull from the cables until you get way over, knees towards the ski tips, then you finally run out of play in the system and lever the tips over ( I had it on that “picture frame” apparatus again).

It’s just a geometry problem, when and how much the lever comes into play. Putting the T2s into the same binding gives much more and earlier tip pressure.

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lowangle al
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Re: Physics debate

Post by lowangle al » Sat Jan 21, 2023 8:46 am

I think the guy in the yellow circle demonstrates how GS thinks a cable works.
3E7B7D9A-4B44-44E2-B46A-F80E91FAC9F7.jpeg



mca80
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Re: Physics debate

Post by mca80 » Sat Jan 21, 2023 9:03 am

@lowangle al :lol: :lol: :lol:



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wabene
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Re: Physics debate

Post by wabene » Sat Jan 21, 2023 9:19 am

:lol: :lol: the guy in the yellow circle is brilliant! :lol:



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DG99
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Re: Physics debate

Post by DG99 » Sat Jan 21, 2023 1:42 pm

Is the yellow circle guy acting like a lever, or is he just pushing? Where’s the force vectors over the fulcrum? I don’t get it.

:lol:



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randoskier
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Re: Physics debate

Post by randoskier » Mon Jan 23, 2023 5:10 pm

GrimSurfer wrote:
Mon Jan 02, 2023 7:43 am
This is a noble effort, Martin.

Regrettably, only one side of the discussion was about physics. That side laid out a position and provided a link to a book written by a ski instructor-physicist for a ski instructor association.

The counter arguments have ranged from the laws of physics don’t apply to skiing, gravity doesn’t matter in skiing, and some straw man arguments about cycling.

What’s really happening is that some people are offended by the notion that their views on how a cable binding works might have been wrong.
Only one law of physics is applicable to XCD skiing. This law was postulated by America's preeminent physicist John Lyon (aka Southside Johnny) it states- "Its's not the meat it's the motion"



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randoskier
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Re: Physics debate

Post by randoskier » Mon Jan 23, 2023 5:11 pm

mca80 wrote:
Sat Jan 21, 2023 9:03 am
@lowangle al :lol: :lol: :lol:

hahahahaha good un



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TallGrass
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Re: Physics debate

Post by TallGrass » Fri May 12, 2023 4:23 pm

For any "Tip Pressure" measured, how do you separate any from the cable, from any from the shoe/boot flex?

I would think if you took a 3-pin binding * WITH a cable and measured with and without the cable attached would be one way.

* A profile photo of the boot in the binding both at rest and flexed for each would also need to be included.



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Stephen
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Re: Physics debate

Post by Stephen » Fri May 12, 2023 6:16 pm

@TallGrass, did you just wake up from a long nap?
:lol:



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