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What does extra DIN accomplish?

post #1 of 26
Thread Starter 

That is, if you don't pre-release, does the tighter DIN itself help stabilize you while racing?

post #2 of 26
I don't think so. I've prereleased a number of times, including a couple of times in races. I didn't feel any kind of problem or difference in how the ski handled until the moment it jumped off. That's what makes a pre-release kind of exciting. If you could feel that you were about to pre-release you could back off....

I think the way bindings work is once they begin to release that's it, they are gonna come off. Consider the boot twisting sideway while held by the levered parts of the toe piece. Once you reach the threshold force and one of the the levers begins to open, the boot gets more mechanical advantage. This lowers the effective threshold and thus the process is pretty much unstoppable once begun.

Obviously if you were just at the threshold you might feel some instability, but in practice the threshold is quite sharp. So for all practical purposes, either you are stable on the ski or it releases.
post #3 of 26

What he said.  All bindings have some degree of anti-shock stuff built in to try to prevent pre-release.  But when you exceed the DIN setting, you eject, if you stay under the DIN setting, you stay in.  DIN settings for racing are a real controversial subject, and are up to each user.  Too little, and you pre release, which not only costs you the race, a pre release at race speeds is not a healthy thing.  To much and you don't release at all...also a decidedly unhealthy occurrence...

 



 

Quote:
Originally Posted by hyperkub View Post

I don't think so. I've prereleased a number of times, including a couple of times in races. I didn't feel any kind of problem or difference in how the ski handled until the moment it jumped off. That's what makes a pre-release kind of exciting. If you could feel that you were about to pre-release you could back off....
I think the way bindings work is once they begin to release that's it, they are gonna come off. Consider the boot twisting sideway while held by the levered parts of the toe piece. Once you reach the threshold force and one of the the levers begins to open, the boot gets more mechanical advantage. This lowers the effective threshold and thus the process is pretty much unstoppable once begun.
Obviously if you were just at the threshold you might feel some instability, but in practice the threshold is quite sharp. So for all practical purposes, either you are stable on the ski or it releases.


 

post #4 of 26
You can also look really foolish in front of an appreciative audience, like the time I jumped out of both skis just after crossing the finish line. As my skis came round in a hockey stop i suddenly found myself sliding on my butt straight for the fence. I got an excellent round of applause :-)
post #5 of 26
Quote:
Originally Posted by Vitamin Ski View Post

That is, if you don't pre-release, does the tighter DIN itself help stabilize you while racing?


No.

 

post #6 of 26
Quote:
Originally Posted by Skidude72 View Post


No.

 


^^^ wat he sed. ^^^

 

post #7 of 26

It is digital, the binding is either open or closed. I tried racing at my normal DIN setting and had a prerelease turning in a deep rut. The trick is finding the point at which my 2 objectives are met: the skis stay on when I don't fall, and the skis come off when I do.

post #8 of 26
Quote:
Originally Posted by vsirin View Post

It is digital


I think what you mean is "it is binary."

 

In any event, that's right. The purpose of having an adjustable DIN is to set the point at which the binding releases.

 

All bindings have some anti-shock capability* engineered into them, but that's a matter of the fundamental binding design, and isn't something you really adjust DIN to affect.

 

In my experience, I need to go up by about 2 steps in going from free skiing to racing. A setting that never inadvertently releases while free-skiing will release fairly often in a race course. This obviously isn't an iron-clad rule, as it depends on how you ski (especially how you free ski, I suppose), weight, etc. Anecdotal evidence from others suggests it's a fairly reliable rule of thumb, though.

______

"Anti-shock capability" means not releasing in response to a large force of very short duration, while still releasing in response to an the same (or, ideally, a lesser) force of relatively longer duration.

post #9 of 26
Quote:
Originally Posted by sjjohnston View Post


I think what you mean is "it is binary."

 

100% correct. Thanks for correcting my usage error. I could not even do a convoluted salvage of the "digital" since I don't use my fingers to change the DIN.

post #10 of 26
Quote:
Originally Posted by vsirin View Post

100% correct. Thanks for correcting my usage error. I could not even do a convoluted salvage of the "digital" since I don't use my fingers to change the DIN.



Speaking of digital. does anyone remember the electric atomic bindings? I wonder what happened to THAT idea rolleyes.gif

post #11 of 26

It's really hard to tell what happens when a binding releases from sudden impact with a rut, but it's not that hard to figure it out.

 

When you increase the point at which the binding will release, you do so by tightening the spring.  The force exerted by the spring is F=kx, where x is the displacement and k is a constant for the spring.  The force applied by the spring is greater at the end of the release, but is also greater at the beginning of the movement.  That means that the force aligning your boot to the ski and the re-centering force that brings it back into alignment after a "knock" is greater for non-release events too.  So yes, I believe it makes a difference, even if your ski never releases, and even if you don't notice it.

post #12 of 26

I disagree. The mechanism is not a simple spring (which would imply that Hooke's law applies). It's a mechanical device designed to be non-linear. Tightening the spring changes the threshold of the mechanical device. When you apply a force to the boot it does not move in the binding at all (or very little) until you reach the release force, at which point the binding suddenly opens.

 

Consider an over-pressure valve on an oil pump. You set the pressure at which it releases by tightening up a spring. If the pressure is under the threshold, no oil at all leaks out. If you exceed the pressure, it suddenly opens and lots of oil leaks out. My understanding of a ski binding is that it's this basic form of pressure release, i.e. all or nothing.

 

Mark

post #13 of 26
Quote:
Originally Posted by hyperkub View Post

I disagree. The mechanism is not a simple spring (which would imply that Hooke's law applies). It's a mechanical device designed to be non-linear. Tightening the spring changes the threshold of the mechanical device. When you apply a force to the boot it does not move in the binding at all (or very little) until you reach the release force, at which point the binding suddenly opens.

 

Consider an over-pressure valve on an oil pump. You set the pressure at which it releases by tightening up a spring. If the pressure is under the threshold, no oil at all leaks out. If you exceed the pressure, it suddenly opens and lots of oil leaks out. My understanding of a ski binding is that it's this basic form of pressure release, i.e. all or nothing.

 

Mark


That would make sense if there was no elasticity/pre-release movement in the binding ie it was a simple binary off/on switch.  However, given that in a decent binding there should  be a certain amount of travel (elasticity) before release that will recenter the binding if the release threshold is not reached I am not so sure this applies (In the oil pressure example this would be equivalent to a blow-off valve to relieve some of the pressure build -up).  Following this logic the level of recentering (pre-release) force should also be increased as the din is increased.  If you set the din low enough and watch carefully you can sometimes feel/see this recentering force (unless of course it is a Marker smile.gif)

 

post #14 of 26

I basically agree with hyperkub, with the additional observation that there's a degree of variability in design among various bindings. All of them are designed with some anti-shock capability, i.e. the ability to take the energy from a short-lived force (what's usually called a shock) and store it so that the binding doesn't release unless the force lasts longer. To use an electronic metaphor, they have something like a capacitor (an actual engineer could presumably express this using correct technical terminology). The simplest way to do it is to put the energy into compressing a spring. The amount of movement associated with the storage may be different from some design than others.

 

In any event, you adjust your bindings for their release behavior, not for what they do before release.

post #15 of 26

Despite the fact that the geometry of the mechanics linking the spring to the other binding parts may change the linearity or non linearity of exactly how much force is being exerted during your boot's travel away from centre, the fact remains that the initial re-centering force and the force along the entire travel path is greater when the DIN is set higher, even if you don't release.  If you don't believe me, try it by hand on a bench with the DIN set two low settings.  You will see a difference.

post #16 of 26

I don't disagree, but:

 

Anybody who's setting his bindings to avoid shock absorption is confused. If that's what you want to do, just bolt the binding to the ski and be done with it.

 

If you want to minimize movement associated with shock absorption, get a different binding design. If you can feel the difference, you are sensitive indeed.


Edited by sjjohnston - 2/2/12 at 4:51pm
post #17 of 26

I ski on 13, 5'8", 165, 295 boot sole.

 

My type three setting is 8

My type three + setting is 9.5

 

I don't race but ski every day in the rockies, higher speeds DO generate higher forces.

 

Just ask yourself which is worse, pre-release into the woods or rocks, or a blown knee.

 

It is a personal decision.

 

P.S.- no blown knees so far (46) KNOCK WOOD!

post #18 of 26
Quote:
Originally Posted by sjjohnston View Post

I don't disagree, but:

 

Anybody who's setting his bindings to avoid shock absorption is confused. If that's what you want to do, just bolt the binding to the ski and be done with it.

 

If you want to minimize movement associated with shock absorption, get a different binding design. If you can feel the difference, you are sensitive indeed.



The question wasn't should you set your DIN higher to obtain greater sub-release re-centering forces; it wasn't would you notice; it was does a higher DIN do anything except set the release point.

BTW bolting the boot to the ski would have very little shock absorptionsnowfight.gif; you need movement for that.

 

I understand some might want to hide the truth so as to avoid misguided people using it as an excuse to set their DIN higher, but I think the truth should be told nevertheless. 

 

I will agree that the only thing you should consider when setting the release point is the danger of retention when you want release verses release when you want retention.    Off the trail and in the trees at 70 mph 'cause a frozen rut knocked a ski off vs having your leg ripped off 'cause the ski didn't release on a wide open trail.  Depends on where you make your turns and how fast you ski.

post #19 of 26

> BTW bolting the boot to the ski would have very little shock absorption

 

Well, yes: that was my point. What I said was if you want to avoid shock absorption, bolt your boot to the ski (actually I mistyped "binding" instead of "boot," but you correctly interpreted it).

 

The actual question was:

 

> does the tighter DIN itself help stabilize you while racing?

 

No, it doesn't in any practical way. If you give a very literal reading to the term "stabilize," you can give an answer that's misleading in light of context and situation in which the question was asked.

post #20 of 26

I think the thing everyone should be concerned with here is forward pressure, not DIN. Going above or below the recommended amount does change the feel of the ski. I know because I've played around with it. Amazingly, most people don't know it exists and have it set wrong, but until the ski is completely off, I'd say it's more important than DIN. I personally cannot tell a difference between DINs other than pre-releases/no release in a crash. I use Rossignol FKS bindings BTW.

post #21 of 26
Quote:
Originally Posted by Vitamin Ski View Post

That is, if you don't pre-release, does the tighter DIN itself help stabilize you while racing?

In the effort of helping you out:

 

If you feel unstable it is not your DIN.  What is could be is (no particular order):

 

  1. Boots too tight - if your foot is "pinned" it wont be able to react and balance properly thus making you feel unstable.
  2. Boots too loose - if you foot is moving in the boot, it wont be able to transmit moves to the ski properly and you will feel unstable.
  3. Alignment is off - if your alignment is off, you wont be able to stay stacked when the forces load up, and your ski will wobble laterally and you will feel unstable.
  4. Your technique is off - if you are not actually carving but rather skidding sideways particularily in a race course with ruts, you will feel unstable.
  5. Your line is off - if you are skiing a line that is contratry to everybody else, you will constantly be cross  rutting which could make you will feel unstable.

 

 

Having said that, based on your posting history I would look closely at #1, and #4.

 

post #22 of 26

So I wonder if the pair of DIN 30 marker's I have are a tad excessive?   To be honest, I wonder what in the world would warrant a DIN 30 setting?

post #23 of 26
Quote:
Originally Posted by TuckerDH View Post

So I wonder if the pair of DIN 30 marker's I have are a tad excessive?   To be honest, I wonder what in the world would warrant a DIN 30 setting?



Markers? smile.gif     

post #24 of 26

Yes, they are Marker Comp 30 that came off a pair of Jimmy Cochran's SL skis that went back to Volkl....  Thick single toe lift and all... 

post #25 of 26

Little bit of info on the Marker bindings and pre-release. I've skied M48 Racings for 20 years (always released as required, just switched over to new skies and have Dynastar PX15 Race bindings) pictrues attached:

IMGP0088.jpgIMGP0087.jpgIMGP0089.jpg

 

The full BIOMETRIC toe (still used) preloads the toe during upward pull of the toe and allows the toe to release sideways if required to prevent rearward twisting fail injuries.  Works very well...too well.  (sorry don't have any of the original MARK hype on this feature).

 

I initially hated the bindings as I sat back and constantly preloaded. Solutions, Crank up the toe or change skiing.  Ultimately I figured it out and changed my style of skiing and loved the bindings  Yes the boot re-centered on impact unless of course it was preloaded upwards.  Getting rid of sitting back was hard.

 

Down side, if you race you are going to preload no matter what and the only counter is to crank the toe DIN to counter.  I recently look at the Marker Race bindings and they haven't change much in 20 years except for cosmetics hence the high DINs .

 

I must say I'm impressed with the LOOK (Dynastar) Pivot Toe, doesn't have these issues ( and this toe hasn't change much either).

 

(BTW I talking about major changes, not minor progressional updates, so please don't beat me up on this). 

 

Never had problems with the rears popping, but then I never had the 48's with the rear external springs (nicknamed POP-O-MATICS), Look pivots are similar but don't suffer the same problem, I guess thats why they still make them.

 

Yes, you read correctly the  skis are 205's, new skis are 176's.

 

My advise is look at your style of skiing and if you lift on the toe at all you're going to hate the MARKERS.

 

 

 

post #26 of 26
Thread Starter 
Quote:
Originally Posted by Skidude72 View Post

In the effort of helping you out:

 

If you feel unstable it is not your DIN.  What is could be is (no particular order):

 

  1. Boots too tight - if your foot is "pinned" it wont be able to react and balance properly thus making you feel unstable.
  2. Boots too loose - if you foot is moving in the boot, it wont be able to transmit moves to the ski properly and you will feel unstable.
  3. Alignment is off - if your alignment is off, you wont be able to stay stacked when the forces load up, and your ski will wobble laterally and you will feel unstable.
  4. Your technique is off - if you are not actually carving but rather skidding sideways particularily in a race course with ruts, you will feel unstable.
  5. Your line is off - if you are skiing a line that is contratry to everybody else, you will constantly be cross  rutting which could make you will feel unstable.

 

 

Having said that, based on your posting history I would look closely at #1, and #4.

 


Re: number 4, I'm not a pro racer, but skidding isn't my problem.

 

Re number 1... are the forefoot and midfoot supposed to relax completely as though they would if you were in bare feet bearing weight? (at least to have maximum stability)?

 

Re number 3, I think that is an issue to some degree... but I'll deal with it when I deal with it.

 

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