Should there be another way of calculating DIN settings?

I ask this question because according to all the tables, my DIN setting varies by 1.5 points depending on how much breakfast I have eaten. My current weight hovers around 174-175 lbs which is right on the border between two of the categories in the table, and my boots are 4mm from putting me in another category as well. If I lose a pound and switch to boots 4mm longer than my current ones, my calculated DIN setting changes from 9.5 to 7. So I am currently using an intermediate setting.

But it got me thinking that surely the relationships between the personal information and the calculated setting must be more linear than the distinct categorising that the tables currently use. The tables are fine if you want to post something on a wall for reference, but a pocket calculator or spreadsheet could easily smooth out the category jumping style of the tables.

If someone re-visited the original source data that was used to devise the tables in the first place they could come up with a more meaningful calculation and do away with some of the assumptions needed to make the table simple to work with.

while my dilema with DIN charts is a little different, I agree there seems to be some room for improvement. My problem is according to DIN charts I should be at an 8 (for a type 3 skier - most shops on the East that I've seen do not acknowldge the 3+ rating). However, its always amusing to tell a tech, 5'8" 240 type 3, 25 years old - I'm sure you can imagine the looks (imagine the looks when at 17 the specs were the same). Problem is that, in years past, I have had people stand on my tip and tail and litterally pulled my boot out of my binding (vertically), that's not too reasuring for me.

I've learned that whenever a tech touches my skis to immiatly ask to use a screw or posi-driver to re-set my DIN's. I know personally, I prefer to teach with 8 - 10 DIN (depending on level), ski 10 - 12, and big mountain/race 12-16. Now I know this is not normal for most people, but I never had a problem with it, but I do get my bindings checked every year to make sure they're working properly. Furthermore, I have worked with a few very good shop techs to derive the DIN's I ride, so they are not just arbitrary, as I would never recomend others go that high.

The biggest problem I see with the DIN charts is they are a standard in a variable situation. 1 DIN refers to a distinct numbers of kilo's of pressure created (cannot remember the amount off hand), but, very similar people could generate totally different amounts of pressure during a fall. Add to the insurance being what it is and the fact that we live in a liturgious society, and the charts are going to be a CYA chart, for most people they will be a little low, to ensure that the general consumer doesn't get injured by a ski not popping off.

I just think they need to rethink skier type, and break it down more, maybe 5 catagories, and tighten the weight ranges diminish the height factor ( if I were a few inches taller my DIN would be recomended higher, but it gets capped because of only being 5'8"). Furthermore, they need to be universal, I never knew type 3+ exsisted until I was in W/B, back east I had never seen it.

Sorry for my rant and if I went a bit off topic or strayed, but this stuff has bothered me for a while.

I think the din tables are pretty conservative and likely good for the average skier. Most people want their ski to release fairly easily and the recommended settings are going to be okay even at +/- 1 setting. Once you reach the skill level where the settings become really important and you don't want the ski to release until a certain point, you've likely got the abililty to judge for yourself.
I think there are way too many factors to cover with a calculation, type of skiing is going to weigh heavily. Obviously a racer hitting 100km/h+ is going to want a higher than recommended din setting. As is someone skiing steep, rocky chutes or hucking cliffs.

The most relevant factor isn't really how much force you might generate, but how much force is likely to hurt your legs. That's mostly a matter of your build: if you're thinking about broken bones, how big and dense your bones are; if you're thinking about knees, how strong and resilient your ligaments are. Short of doing a medical exam, the most practical way of trying to measure this is with a combination of height and weight, with age becoming a factor as well as you get up over 50. The biggest problem with using weight is that it doesn't distinguish between a 220-pound linebacker and a 220-pound couch potato. Throwing in height helps, it's still imperfect.

It's also a matter of boot sole length (at least for the toe), since the binding releases in response to force at the end of your boot, and your bone breaks in response to force at your ankle, and the relationship between the two varies with boot length. Longer boot: same force at toe -> bigger force at bone.

Finally, because bindings aren't perfect, it's a matter of balancing one error (failing to release when you should) against the other (releasing when you shouldn't). The former is more likely if you're moving slowly and suffer a slow, twisting fall in which forces build up gradually. The latter is more likely if you're moving fast and the binding takes frequent short-duration shocks. Also, the latter isn't very dangerous if you're moving slowly on a 9-degree slope, and considerably more dangerous if you're going 60 miles an hour, or if you're on a 50-degree shaft above exposed rocks. That's why to consider skier-type.

I don't think there is any need t rework the current din charts. they are just a guild. I use the Name Utah49 becuse once past the age 50 my DIN setting droped by more then 2 points.Whenever I fill out a card for the techs at my local shop I'm still 49. At a DIN setting of 5 I could walk out of my bindings. For me I feel safe at a setting of 7 to 8. Since I value my knees I never go over 8.

Having worked in a shop for a couple of years, I see the need for an improvement of the DIN chart (maybe I'll come up with a new one). This improvment is more on how it is read, ie. you are supposed to take the lower value of the height and weight. I really don't see the difference in the force generated at the binding for a 6'7 220 lb guy and a 5'5' 220 lb guy, I would almost think the 6'7 guy should have a lower DIN due to his lanky body shape.

With a formula or chart based on a variety of variable such as body structure I would think the calculation would take a considerable amount of time not to mention the fact that a lot of the techs, especially the not too bright ones, would miscalculate the DIN. A few miscalculations could be fatal to a shops reputation.

Just some of my thoughts and observations.

I think that in order to make the tables as simple as possible to work with, they had to make some large assumptions and err on the side of caution in some cases. The most obvious example is that a 5'8" person at 148lbs is presumed to have the same leg strength as someone at the same height but 240lbs.

Presumably the tables are based on the known leg strength of people of a particular height weight and age, but I am sure some of the nuances in this data were lost when these 'rule of thumb' tables were devised. I can't see why someone hasn't gone back to that source data and found a more complex formula which fits the data better which could be built into an electronic calculator. It would allow more subtle weighting of the factors, it may show weight and height are given different importance, and the settings may drop off in a curve with age. Or you could go directly back to the source data and plug the entire database into a calculator which looks up the average leg strength of a person with your characteristics and factor in the effect of the boot sole in a linear way.

The end result may be exactly the same as what you use now, or any difference within the margin of error for the release values of the bindings, but it might prevent errors in reading the tables and give a slightly more meaningful DIN setting.

I seem to recall from my Silvretta binding tables there was an alternative method of arriving at Din settings that called for inputting the measurement of tibia thickness or something in millimeters. I had no metric tape measure so I did not use that method. I have no idea how the outcome might differ. I only know that my own Din settings are ridiculously low if I go by the usual tables. The trade off for protecting your tibia, unfortunately, could be some far more serious injury if you fly out of your skis into a tree or boulders.

Isn't it more about leaverage than leg strength? Just like with boot sole length, height or leg length, affects the leaverage that can be exerted. Weight affects leaverge force, but it is probably not as qualifiable as leaverage. I don't see strength being an issue because we can always get hurt when we aren't exerting our maximum effort in a particular joint, and as far as breaking a bone, strength doesn't really have anything to do with the shear force here.

I'm with Utah49, I don't think it (din) really needs adjusted. I also ski @ 8 and have no problems. I'm 5'-10", 180 lbs., and 52.

The DIN chart is a conservative starting point. There are way too many variables to take into account to create a perfect system. Unless everyone skis the same all the time, then the three main factors of boot sole length, weight and height can be used. There is a redundancy with the skier ablitly scale, because everyone is an expert.

Marker bindings used to come with an alternative method using tibia-head size as the metric for bone strength, instead of height and weight. This was briefly discussed in a thread here some time in the last year. As I vaguely recall, someone chimed in with a semi-authoritative comment to the effect that tibia-head size had proved not to be particularly reliable either. Presumably you can have a wide tibia-head and still have a weak bone.

No, it's about bone, or ligament, strength: how much twisting or bending force your bone or ligament can take before it fails. As you note, it's not muscle strength.

Leverage created by the geometry of the body isn't the issue, it's the leverage that exists simply because you've got a 2 1/2- or 3-foot-long lever sticking out in front and in back of your foot. Anybody of any size or ability, including somebody who's 5'2" and has no muscle at all, can exert a huge force on his tibia simply by skiing at moderate speed and hooking a tip on something.

It's not the force generated, it's the force the body can take before it fails. A 6'7" 220 lb guy is probably a big guy, with big, strong bones. A 5'5" 220 lb guy is probably just fat. Of course, there are "probablies" in both those sentences. It's an imperfect estimation at best.

It seems to me that one issue worth thinking about is that the whole system is more oriented to the threat of twisting injuries to the tibia than anything else. Over the last couple of decades, bindings have got so much better at preventing broken legs, that knee injuries have risen in importance (sort of like the huge reduction in mortality from infectious disease in the last century raised the importance of heart disease and cancer).

I don't know how much thought has gone into ligament strength (and resiliency ... which I suspect drops a lot earlier with age than bone density) as a factor in binding settings. Also, there may well be room for improvement in the way current binding designs protect the knee: particularly the ACL.

din standards

Some comments:

DIN standards were developed in the late 70s in europe. They are averages, just like weight charts. The settings are very conservative as all the retailers are indemnified by the industry. Skiing got a lot safer with the DIN standards. DIN is testing organization like ASTM in the USA.

However, they do not take into account variations from the norms...like ideal weight charts do not differentiate between muscle and fat or bone structure. Anyone who is a true expert, elite racer, extreme skier does not go by these charts. Marker world cup bindings used to go up to a DIN of 24 and you could only buy retail bindings at 14 as I remember.

I am 6'1", 195, type 3 but 62 years old. After 50 the setting goes down 1. I cannot stay in the recommended setting and still set my own bindings 1.5-2 above the standard. As a younger racer and back country skier I used to set my bindings much higher....the price for coming out was worth risking a knee injury. My current settings seem to work fine and I come out when I should.

Bindings do not protect the weak knee structure well. They do protect the lower leg well but the knee is a weaker structure. The manufacturers are still working on the problems of complex falls and protecting the knee. Some day.

The shop that I have worked for many years now will set for type 3+ or even more if the skier signs a waiver.

Overall, DIN standards have made skiing safer for the 75-80% who are causal, occasional, recreational skiers. Risk Takers are off the chart, so consult with a good technician before deviating.

When I started skiing more than 50 years ago leg breaks were the norm...today it is knees. Knock on wood...none so far.

It's not the force generated, it's the force the body can take before it fails. A 6'7" 220 lb guy is probably a big guy, with big, strong bones. A 5'5" 220 lb guy is probably just fat. Of course, there are "probablies" in both those sentences. It's an imperfect estimation at best.

I also agree bindings are much safer then before and injurieries typically involve the knee. But realistically how would one really measure how much a person's knee can take, let alone do it in a short period of time. If bindings were set for each individual person there would be a line running out of the shop just to measure people so their bindings could be mounted.

I've heard from one of our machine servicemen that measuring the tibia length is a method more common in the european nations. I would think the weigh and height started to be used here as a way to save time. It would be interesting to see a study done to determine if there is there is much of a difference in the DIN setting between the two.

I don't even think they are averages. Think what the weight charts would look like if there was only 6 categories each for height and weight. The source data the binding release settings are based on would have had information on the average leg breaking force for a great number of people of a particular height, weight and age. But the method of converting that mountain of data into a few easy to use categories, meant that for each category they had to use the lowest average in that group, even before factoring in a large buffer margin.

What I am saying is, that with the advent of elactronic calculators and databases why not go back to that source data and let a computer chip go through the process of estimating your leg breaking force, based on the actual test results on height, weight and age. It could build in a buffer margin for each skier depening on whether they prefer release or retention, then factor in boot sole length to get a final DIN setting. This would avoid some absurd results like dropping 1.5 points when I lose a pound of weight or not being able to give a good estimate for those with unusual combinations of height and weight.

Tibia head measurements may or may not be valid, but I don't trust shop techs enough to make accurate medical measurements when my body is at stake. The ultimate solution however might be to undergo endoscopic surgery and let a surgeon examine the size and condition of your ligaments to get a better estimate of their breaking strength.

Unfortunately, no reasonable DIN value can protect your knees from backwards twisting falls.

Binding design has not adequately addressed this yet, IMHO. Frankly, I find it terribly sad that most of the bindings on the wall are functionally equivalent or similar to their forebears at the end of the 70's.

Eventually, bindings will rigidly hold your feet with nothing but a tiny amount of elastic travel. Force sensors will determine the loads present at the attachment points. Software will determine when to make the binding release.

Such a design would drastically improve the ability of the binding to release in backwards twisting falls, and drastically improve the binding's resistance to pre-release.

Meanwhile I'll stick with the lowest feasible DIN, in the bindings with the greatest amount of elastic travel possible. People can ballyhoo bindings all they want, but very few bindings allow me to ski confidently at a DIN/ISO of 9. (Its actually an ISO norm now....DIN refers to the original standard)
-Garrett

Yes, it is rather annoying sometimes when people are "caught out" by the chart. In reality, some of that is due to binding limitations. Really tall and light guys will forever break more legs, because they need a higher DIN to keep them in the ski, despite the chart correctly predicting their risk level. Some people just have to deal with a higher risk level.
Lots of shops now DO use such an electronic calculator. However, they do so for accountability and accuracy's sake, not to increase the resolution of the chart. Since the standards and indemnification agreements don't address the (rather intelligent) idea you provide, no shop is going to "stick their neck out" and see what the courts or insurance companies might say.

FWIW, the people with electronic binding testers often do adjust bindings by .25 points after a torque test, which is a resolution of adjustment often missed by a tech with a Vermont Calibrator, aka torque wrench. It shouldn't be, but lets face it, machines have more repeated accuracy than ski shop employees.
The bindings don't protect your ligaments. There are many situations in which you can tear a ligament with a Skier Type One setting, or any other setting. Those situations need to be addressed via binding design.

If you are worked up about this because of the fear of ACL injury, I understand your concern. The only thing that will protect your ACL is good strength training, good technique, and knowing when to quit.
-Garrett

Yeah, I've thought the same thing.

One would think that the technology necessary to produce such a binding is readily available today: all you need are 5 or 10 sensors at critical points, a trivial microchip, the software and a mechanical release system. The sensors wouldn't be enormously expensive, I don't think. The microchip would be dirt cheap. The software wouldn't need to be complicated to be better than current bindings: you want to get some medical advice about what particular combinations (simultaneous upward and sideways forces at the toe, e.g.) should lead to a release. The more work you put into it, the better it would function, but it wouldn't take a lot to make it better than a purely mechanical system. The mechanical release system should be doable: similar sorts of electro-mechanical relays have been all over the place for years.

Agreed. But what would the capital investment be? 5 million? 20 million?

Why do that when you can simply take the same binding you've been building for 25 years, spend a couple hundred grand on new injection molds for a "new look" or "new attachment system" and then sell the thing for 300 bucks?

When customers are willing to fork over gobs of money for woefully inadequate product, why mess with a good cash cow?

Line tried to build a better (mechanical) binding...and they have met stiff resistance from the whole industry. Big surprise there.
-Garrett

Your are correct

I think you are correct. I have seen the methods used but it has been at least 25 years ago and my recollection is now that good.

However, it did improve safety tremendously for the recreational skier but the DIN charts don't serve the racer, extreme skier, stronger skier, mogul skier well.

I am in my 60s but very fit and if I set my bindings at the recommended settings I would be on my butt all the time. Years ago we used the simple test to twist out of the heel and to twist out of the toe....not very scientific.

As for computer chips....I think Atomic has some intelligent bindings this year. I have heard there is a lot of development in that area but don't know any inside information about them.

Yes, I can't wait for the reports of skis that go "The skibindingControl program has performed an illegal operation and will now be shut down. Your ski will now detach." as you ski. Confidence inspiring.

It was meant to reduce spiral leg fractures. It did so beautifully.

It is a chart based on risk level. Type II and III simply mean "willing to accept a higher level of risk". Racers/etc need to accept higher levels of risk than the chart allows, but don't think for a moment that a "strong skier's" tibia is any stronger than an average Joe's. The stronger skier is willing to accept more risk if he/she screws up, partially because he/she is less likely to screw up.

I get really defensive when people accuse the chart of doing a poor job. It does a wonderful job. I would call myself a strong skier, and a fairly strong guy. In good bindings, I can ski at Type III without more than a half dozen pre-releases per season. In some manufacturers' bindings, I can't keep the skis on for 10 seconds at that setting, but that is a different issue.

The chart is about risk. It predicts risk level quite well. Perhaps higher resolution would be nice, but the concept is based on solid scientific data that applies every bit as much today as it did 20 years ago.

The real issue, is that binding technology SHOULD progress into an area where it can protect ligaments as well as bones. That will require a capital investment on someone's part, and why do that when you can stuff a 15-25 year old binding on a ski and charge someone 300 bucks for it?
If I set my bindings so I could twist out standing still, I wouldn't stay in very long. My Type III setting makes that possible, but very difficult.

Depending on manufacturer, my Type III setting is 9 or 8.5.

I'm a lot younger than you. Probably a lot stupider too. The two go hand in hand. Perhaps you should consider this: Although your muscles and technique may allow you to keep up/kick my ass down the hill, is your bone density the same as mine? Is your tibia going to hold up to the bending or torsional stresses that it would have 30 years ago?

The chart predicts risk. Its my feeling that as you have gotten older, you've had to increase your risk level in order to stay on the hill having a good time. You must understand that you are more likely to go out and break a leg now than you were 40 years ago, at my age...all other things being equal. I don't see how you can blame that on the standard...unless you believe the standard should allow more risk for older people.

Admittedly, the arbitrary 50 year old cutoff is, well, arbitrary. I definitely believe a better job could be done on that front.
The Atomic binding is an expensive toy, no more. I check my forward pressure every time I put my skis on. It takes me about 2 seconds to do. Working in a shop, my skis/bindings get screwed around with too often to not check my forward pressure.

I suppose that if I couldn't reach down to/look at my heel piece the Atomic binder might be worth the extra grand.

The computerized binding I want to see would make release an electromechanically completed event.
-Garrett

Speaking as a 6'6" 265 lb guy, I'd say that a 6'7" 220lb guy is probably very lanky/skinny. Not sure how this would affect DIN settings. He probably wouldn't sink in powder as deep as I do ;-)

Oops. I think I meant to type 6'3", and it just came out as 6'7". That would be on the skinny side. Also really tall.

I'd like to see Manute Bol on skis. I'm not sure why.

Yes.

One side note, about risk: it's not entirely about willingness to accept risk, but also balancing one risk against another. A premature release isn't just an inconvenience, but poses a risk in itself.

From what I've seen (admittedly not much), the new Atomic binding does look like a bit of a joke. Like they decided to put a chip in there so they could charge more, and then they had to figure out something trivial for it to do. Maybe it's a "toe in the water" for a real electronic binding.

I don't know that the capital investment to create an electronic binding would be insurmountable. The biggest problem would be trying to sell the thing. The existing manufacturers have a huge advantage in brand recognition and an even huger advantage in distribution. Ski equipment is (mostly) still sold the "old-fashioned way," through brick-and-mortar retailers. Unless you could get this binding on their racks, I doubt you could sell enough to make a go of it.

(And I can twist out of my bindings at 8.5, for what that's worth )

Wow. I consider one a year too many.

Well, I do as well.

That is why I crank it up a wee bit.

As a control, I skied in a Rossi WC binding at Type III last year. Rossi/Look Type III is 8.5 for me, rather than 9.5 for the rest of the manufacturers, due to the bootsole cutoff on the Rossi/Look chart.

Didn't pre-release until I made a less than athletic move on a particularly firm course.

Raised the setting to 10.5, and didn't release for the rest of the season. Try that in an Atomic.
-Garrett

I ski 95% of my time on Atomic bindings, set 2 up the DIN chart for rec skiing and 3 for racing. I have not had a pre-release in a couple of years, and always come out when needed. I don't believe I have ever had a pre-release from my Atomic bindings, actually. I used to have that trouble years ago on Markers.

Yeah, ok.

In the Atomic 614, my heel DIN got to 14 before I could reliably stay in it in the racecourse. I weighed 185lbs then.

That was with the forward pressure aggressively set, and a new boot in a (new that year) binding. Since I function test ski bindings on a weekly basis in the winter, I can tell you that Atomic failures are more common than most other brands..

Even when the binding is "working" as designed, the amount of elastic travel is downright pathetic. It requires a higher DIN setting to keep you in the binding a reasonable percentage of the time.

If you have the finesse (it speaks well of your skiing, that you can stay in those bindings at those settings) to stay in your Atomics that well, you could probably go ski a Look at Type II all the time without a pre-release, never needing to bump the setting up for a "race".
-Garrett

I have heard of quite a few cases here and know personally of a couple more where people have to crank their settings up a couple of points on their Markers and Atomics compared with Looks to get pre-releases down to a low number. I think it is down to the lack of shock absorption from the pathetic elasticity which means that if you hit any irregularity at speed these bindings will just jettison you.

I actually ski my Looks slightly lower than my recommended setting and have never had a pre-release in four seasons of hard skiiing.

I cranked my Markers up a bit because I absolutely despise the top-toe release. I wanted to make sure I stayed in. While for the general consumer, the top toe release is a very valuable release mechanism, I personally do not like the idea that my toe can release vertically. I just wish Marker would put an on/off switch or something, so it can be turned off.