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# stand height & delta angle illustrated

Here is a little graphic to chew on....hope it works

Nothing happens. I click on the link and it turns red. That's all.
Doesn't work for me either -- I just get a "the URL is not valid" pop-up box.
Pretty informative diagram Bud. Nice work!

ps. I had to copy/paste the link into my browser.

Here's a link that should work.
I just fixed the first post. Should be fine, now.

Bud, I thought "stand height" was the height of the binding from the snow! Shows what I know. At least I had "Delta angle" understood correctly...
You sure about that trigonometry?
I snapped a boot into the bindings on each of my three main pairs of skis and measured the stand height, toe and heel, for each. As I'm using the term "stand height", I mean the distance from the botton of the boot to the base of the ski.

Weirdest thing. On one pair of skis, the difference between toe and heal was one, maybe one and a half mm. That pair of skis is the easiest turning that I have, even though it's the longest. Go figure!
Quote:
 Originally Posted by oboe I snapped a boot into the bindings on each of my three main pairs of skis and measured the stand height, toe and heel, for each. As I'm using the term "stand height", I mean the distance from the botton of the boot to the base of the ski. Weirdest thing. On one pair of skis, the difference between toe and heal was one, maybe one and a half mm. That pair of skis is the easiest turning that I have, even though it's the longest. Go figure!
I have always understood (from working in the industry) that stand height of a binding is heel height at contact load bearing point minus toe height at AFD. The ski does not factor into the scenerio unless you want to cloud the water.

Realize this angle is only part of the formula and there is no RIGHT angle to be replicated for everyone. Because of all the variables it is a stack of cards that must be evaluated with a trusted one (boot ramp, footbed ramp, tib/fib length, dorsi flexion, foot length) Ah!....but once you find the perfect spot (no we will not name it that!) take note so that it can be replicated on all your equipment in the future. And, YES a millimeter does make a difference! and 1 degree in angle is VERY noticable!

A gross generalization would be that a skier with a size 14 boot in an Atomic (one of the flatter stand height bindings) would likely be on too flat, where a skier with a size 4 boot in a Look binding (historically one of the higher stand heights) would likely be tipped at too great of an angle.
I've also heard "stand-height" to mean the full height from the bottom of the ski to the bottom of the boot: as when people say the maximum allowed stand-height is 55 mm. Then again, neither the FIS nor the USSA actually uses that term in their rules (the FIS just says "height" and the USSA says "stack height"), so I guess it's meaning is fair game.

I've heard "delta" as the difference between the heel height and the toe height ... "delta" as in that Greek letter that looks like a triangle and is sort of a standard symbol for the difference or change from one value to another.

But that's just what I've heard.
In reality, the stand height in binding that we are focus on here is the DIFFERENCE BETWEEN THE HEIGHT OF TOE AND HEEL. So if you want to add in your ski....go for it because the ski should offer little or no difference in the angle unless you are mounting way ahead or way back of thickest part of ski. My version is meant to allow people to choose their bindings know ahead of time, before they have mounted them, what affect they will have on their stance. The ski angle, if there is one created will be the same no matter what binding in attached to it so why add another variable in the mix.

yes, FIS measurements are for a different reason alltogether and they are talking strictly height from the bottom of ski. There concern is leverage not what angle is being used.
It was just easier to meaure from the bottom (edge) of the ski. The difference between toe and heel was just the same as it would have been had I measured from the actual boot toe and heel.
On a side-point, here are the degree values I get for the table of boot-length and difference-between-toe-and-heel-height (whether you want to call it stand height or delta or something else):

____3___6
260 0.7 1.3
280 0.6 1.2
300 0.6 1.1
320 0.5 1.1
340 0.5 1.0
360 0.5 1.0
380 0.5 0.9

I used arcsin(delta-in-mm/length-in-mm). It's entirely possible I did something wrong. The original figures initially looked a little too linear to me. Plus, in the original table, it sure looked like the next value in the right column (for 400) was going to be less than .7 ... the top value in the left column implies that you don't get to .7 in the right colun until the sole length is around 520.

Figures are in degrees, rounded to the nearest tenth.
bud, from the Dynastar website, emphasis added:

Quote:
 EXCLUSIVE 9 AIS W Fashion Rider Profile Good women skiers looking for a stable ski to progress with more control and more confidence Advantages Control, stability Autodrive W Exclusive Double Platform Fore/Aft balance Raised heel Good edge grip Autotdrive W Exclusive Double Plate Level Intermediate-Balance / Control Terrain Allterrain Technical Features Sandwich
The measurement of delta is of interest to me, but of even greater importance: What does it do?! I always thought I needed great lift at the heel. Now that I've actually measured stand height differences on all of the skis I use, I find that the one with the LEAST difference is easier to ski! The stand height difference on that ski is 1 mm difference, heel high. The others are in the range of 3 mm to 5 mm with a boot sole length os 291.

What am I failing to understand?!:
Quote:
 Originally Posted by sjjohnston On a side-point, here are the degree values I get for the table of boot-length and difference-between-toe-and-heel-height (whether you want to call it stand height or delta or something else): ____3___6 260 0.7 1.3 280 0.6 1.2 300 0.6 1.1 320 0.5 1.1 340 0.5 1.0 360 0.5 1.0 380 0.5 0.9 I used arcsin(delta-in-mm/length-in-mm). It's entirely possible I did something wrong. The original figures initially looked a little too linear to me. Plus, in the original table, it sure looked like the next value in the right column (for 400) was going to be less than .7 ... the top value in the left column implies that you don't get to .7 in the right colun until the sole length is around 520. Figures are in degrees, rounded to the nearest tenth.
One thing you need to consider is the angles I got were derived from using a boot sole contact point on the binding itself not the very tip of each end of the boot. the boot contacts the binding on a shorter base and consiquently affects the angle. I used a digital inclinometer and rounded for simplicity to demonstrate a point. What is Trigitmotree! I think I have one in my back yard...
Bud:
I also would have used stand height as the distance from the bottom of the ski to the bottom of the boot at the highest point, not including sole cutouts. Probably at the back of the heel. Anyway that is high I measure it for FIS skis.

However, in the end the terminology isn't important as long as everyone can interpret what is being said. I do question one of your points concerning boot length and its affect on delta. Certainly boot length affects delta but I don't think it is proper to say that with the long boot delta will be to low.

In my opinion the delta is additive to the zeppa angle and it really doesn't matter where the angle comes from. If the zeppa and florward lean angle is correct for the skier I think the binding delta angle should be zero.

What is your point-of-view?
Stand height is from the base of the ski to the sole of the boot measured at the heel. (FIS' term adopted by the manufacturers)

What you have called stand height is called RAMP. What you have called Delta angle is called RAMP ANGLE. Delta is a boot term referring to the difference in height between the toe and the heel.

Sorry, but this interweb is confusing too many people already. If you want to be informative, give the correct terms.
Whoa Beta! excuse me, but what would you like to name the "difference between the height of a toe piece vs. the height of the heel piece (without a ski involved so that consumers can get an idea of how these binding dimensions may influence their purchase)? I am open to your wealth of knowledge.

What I have called stand height is ramp? What do you call the angle created by the zeppa in the boot? or is it a boot board?

Call these things what you want and I will oblige you. My point is to help people understand how this angle is created and how it changes with boot sole length. You can rewrite if you would like and make it clearer! thanks....
Quote:
 Originally Posted by louis rosenfeld Bud: I do question one of your points concerning boot length and its affect on delta. Certainly boot length affects delta but I don't think it is proper to say that with the long boot delta will be to low. In my opinion the delta is additive to the zeppa angle and it really doesn't matter where the angle comes from. If the zeppa and florward lean angle is correct for the skier I think the binding delta angle should be zero. What is your point-of-view?
Lou, I don't believe I said or at least meant "low" but "lower", sorry for that confusion.

I concur with Jim Lindsey when he promotes matching the "net forward lean" angle (which is the forward lean of the boot less the zeppa angle) to a skier's dorsiflexion angle when the foot is weight equally front and back. This makes common sense to me and I have been using this method. I realize their are things to watch for when doing this that are beyond the time I want to spend here tonight, but this concept makes sense.

Now, once this angle is match skier to boot, I then look at them in the bindings on their skis and look for good angles. leg segment lengths may change what kind of, dare I say, delta angle is needed IMHO, but I agree with you that more times than not less is better and in some cases negative delta is needed.
While Beta's post was a little abrasive, he is still correct.
Later
GREG
I have two questions!

Has anyone ever compared the difference between heel and toe stand height (heel stand height minus toe stand height) on system skis? I have compared the stand height differential on the Fischer RX8 with Railflex and the Dynastar Intuitive 74 with the Look specific "wine-bottle" plate. The Fischer is almost flat, while the Dynastar heel is 15mm higher than the toe if the Look plate bindings are used!

Question # 2. What are the benefits of a reduced differential (low delta angle) and what advantages are there to a high differential (high delta angle)?

Cheers,

Barrettscv
Quote:
 Originally Posted by barrettscv ...while the Dynastar heel is 15mm higher than the toe if the Look plate bindings are used!
Wow! 15mm for the Dynastar/Look combo? Look Pivot series are normally only about a 5mm differential. So you're saying that the Dynastar plate introduces an additional 10mm? In my experience that's quite a bit of delta these days and really unnecessary. The trend in racing plates lately has actually been towards negative deltas (with the toe a bit higher than the heel).

Anyhow, the whole issue as to whether one is better than the other depends on many factors that are best left to a professional (Bud is one of them). Your body stature combined with other equipment variables will set you up as either balanced or not, but generally I would say that trend is to go flatter for modern ski technique.
Whoa Beta! excuse me, but what would you like to name the "difference between the height of a toe piece vs. the height of the heel piece (without a ski involved so that consumers can get an idea of how these binding dimensions may influence their purchase)? I am open to your wealth of
knowledge.

Umm, Ramp? I thought I wrote that.

What I have called stand height is ramp? What do you call the angle created by the zeppa in the boot? or is it a boot board?

Boot board angle?

Call these things what you want and I will oblige you. My point is to help people understand how this angle is created and how it changes with boot sole length. You can rewrite if you would like and make it clearer! thanks

Sometimes trying too hard makes for more confusion. Sure you can call things what you want, but if it is already called something else, why not use that name or term? I am truly sorry that constructive criticism is not an option.
When this thread was created it changed some of the things i knew about the delta angle. But it also created confusion. When Beta posted, i thought his post would create more confusion, but that was not the case. He actually helped me understand things better.

This is how i see these things:

Binding ramp = difference in height between the toe piece and the heel piece (My Markers have 5mm of ramp)

Ramp angle = difference in height between the toe and heel of the bootboard ( measured in mm's)

Delta angle = ??? I read Beta's post again and i still don't know exactly what it really is.

Beta, could you explain please? You said it is a boot term reffering to the difference in height between the toe and the heel. Is this the toe and heel of the boot? If yes isn't this called boot ramp angle?
I am trying to understand better what the delta really is b/c i used this name in a thread and it seemes it was not accurate. I'm sorry for that. I always provided the best info i had on a particular subject (based on my personal experience or someone else's (bootfitters)) and i want to do the same thing in the future.
Thanks,
Jamie
[quote=Noodler]Wow! 15mm for the Dynastar/Look combo? Look Pivot series are normally only about a 5mm differential. So you're saying that the Dynastar plate introduces an additional 10mm? In my experience that's quite a bit of delta these days and really unnecessary. The trend in racing plates lately has actually been towards negative deltas (with the toe a bit higher than the heel).
QUOTE]

My solution was to remove the heel plate but retain the toe plate. The Ski now has the Look plate under the toe and the Dynastar "wine-bottle" plate under the heel. I re-measured and now the delta is still positive, but almost zero.

Barrettscv
[quote=barrettscv]
Quote:
 Originally Posted by Noodler Wow! 15mm for the Dynastar/Look combo? Look Pivot series are normally only about a 5mm differential. So you're saying that the Dynastar plate introduces an additional 10mm? In my experience that's quite a bit of delta these days and really unnecessary. The trend in racing plates lately has actually been towards negative deltas (with the toe a bit higher than the heel). QUOTE] My solution was to remove the heel plate but retain the toe plate. The Ski now has the Look plate under the toe and the Dynastar "wine-bottle" plate under the heel. I re-measured and now the delta is still positive, but almost zero. Barrettscv
Nice. I effectively did the same thing on my Machete FBs and ended up with a 1.0mm delta.

### negative delta ?

Where is your negative delta in racing info coming from? I don't know of any current World Cup racer that has a negative delta plate set-up. Zero, maybe, particularly in slalom, but not negative.

### angle expressed in mm

SYWSYW:
Your understanding of the terms is correct as betaracer explained. However, expressing things in terms of mm accomplishes nothing. 5mm difference between toe and heel may be a lot for a 23 boot or binding set to a 23 boot but isn't nearly as much if the boot with 5mm difference is a 28.

Millimeter is a simple way to express the difference but is completely useless in practice.
I am no geometry whiz but do know that as lou states, angles can not be communicated in millimeters.

and silly me, but when I hear "ramp" I think of angles not specific heights in mm's.

This is in part why I tryed to do the graphic above to demonstrate how different binding heights between toes and heels create different angles that again will change with boot sole length mounted in the system.

I am now confused too and will heretofore try to describe my intent rather than using a term that may be misinterpreted or misused on my part.
Quote:
 Originally Posted by louis rosenfeld SYWSYW: Your understanding of the terms is correct as betaracer explained. However, expressing things in terms of mm accomplishes nothing. 5mm difference between toe and heel may be a lot for a 23 boot or binding set to a 23 boot but isn't nearly as much if the boot with 5mm difference is a 28. Millimeter is a simple way to express the difference but is completely useless in practice.
Louis and Bud, thank you for your replies.

Ramp angle is typically referred to in mm's. The angle increases in shorter boots and decreases in longer boots. Delta angle that is external influences (binding ramp) increases on shorter boots and decreases on longer boot soles.

I measured the binding ramp which is 3mm. I measured the ramp angle which is 10mm (toe=10mm heel=20mm) and i also looked at the graphic and for my size (25.5 MP 294mm) i have just a little more than .5 degrees of delta.
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