There’s a longstanding belief that an extra 500 grams of weight on your foot slows you down much more than an extra 500 grams in your backpack.
I found another reason to doubt that it’s true for climbing up a steep hill with skis on my feet versus with the weight of skis on my pack.
Climbing up a hill at steepness around 16% grade, I got pretty nearly the same time and speed either way . . .
after several weeks of specific
training climbing up with the weight of skis+boots+bindings on my feet.

So if I frequently climb up with skis on my feet, my muscles can adapt to an extra 500 grams on my feet about as well as they can adapt to an extra 500 grams in my backpack.
How frequently?
I think three times a week with one session focused on moving the feet at high frequency and/or long strides is enough to get a reasonable adaptation in 6 weeks or less.
My guess is that twice a week with one focused session would work pretty well—in which case lots of skiers who start in early December and get out for a short intense early-morning or evening mid-week ski would be adapted by mid-January.
. (I’d guess that people who only ski once a week aren’t going to adapt as well)

Adapted? I don’t mean that I could climb just as fast as without the extra weight - (of course extra weight anywhere is always slower) - only that it’s not slowing me down significantly more than the same amount of weight carried in my pack (which also would take time to adapt to).

Seems to me that the muscles used to move the weight on the foot + ski forward up the slope are big leg muscles (hip flexion + knee extension, including the “quadriceps") which are well able to develop in response to specific progressive training stress. Frequent skiers are well able to apply the specific training stress.

So there’s no special advantage of a lighter ski binding versus carrying a lighter camera (or no camera)—for frequent skiers.

But we have this odd result where the skiers who are most able to adapt to the extra weight in their boots/skins/bindings/skis are the most likely to be compromising on reliability, release-safety, and downhill-skiing performance, while those with least time to adapt are more likely to have heavy equipment on their feet.

Who gets the biggest uphill speed benefit from light equipment on feet?
People who only climb on skis once a year on their annual ski-mountaineering trip.

Ken

KenR from USA - 17 December 2009 02:53 PM

But we have this odd result where the skiers who are most able to adapt to the extra weight in their boots/skins/bindings/skis are the most likely to be compromising on reliability, release-safety, and downhill-skiing performance, while those with least time to adapt are more likely to have heavy equipment on their feet.

That is so true. As you know I used to be a bike racer (and I know you are an accomplished cyclist too) and there is a lot of focus on every gramme in cycle racing. I remember reading a book, aimed at time trialling, which said you should forget about weight to a large extend and focus on aerodynamics. The authors suggestion was to use steel cranks which could be ground to a more aerodynamic profile etc. Obviously the rider profile also makes a huge difference. Someone who took this philosophy to its conclusion was the Flying Scotsman Graeme Obree

http://en.wikipedia.org/wiki/Graeme_Obree

anyway with bikes I’m sure there is a limit beyond which it is not worth reducing weight further and there are similar thoughts that lighter wheels (because they rotate) are worth more than a lighter frame. I’ve always found very light wheels to be hard to ride as they are thrown around more by poor road surfaces.

Back to skiing. I use Diamir II bindings but I’m not a big fan of the pivot position and prefer the Silvretta Pure binding. I was touring with a couple of people who were on Emery Energy bindings last weekend. So you can’t fault the longevity of the plate design of binding. I’m sure a Diamir or Pure binding offers better release possibilities than a Dynafit binding and it is certainly easier to use, especially for beginners. Maybe that’s the main reason we see more beginners / occassional ski tourers on them?

Anyway to change the subjec slightly I was in Skalp last week. He is currently stocking 3 Dynafit compatible bindings from ATK, Plum and Trabb. These are competition bindings with a fixed DIN 6 heel release. Alain was very enthusiastic about the Plum binding and it did look really well made. He said that the guy behind Plum was really serious and was going to produce a DIN adjustable heel piece next year. So we will have the G3 Onyx, possible new Trabb binding and Plum competing in the recreational Dynafit space next season. I wasn’t keen on the Onyx, very heavy and clunky feeling although it did seem to work.

I will find Dynafit’s blurb on saving weight and post it.

davidof - 01 January 2010 11:44 PM

I’m sure a Diamir or Pure binding offers better release possibilities than a Dynafit binding

Oddly this is the first time on a forum or magazine article I’ve read someone just say that in plain English.
. (It’s matter of concern to me because two of my favorite ski partners have broken legs skiing on Alpine Touring bindings (not Diamir or Pure)) .

The obvious way to support the claim of “better release” is to say that the main design goal of the Dynafit was saving weight, not release safety, while the Diamir borrowed at least one of its major components from an alpine downhill binding designed more for safety than for weight-saving—therefore it would be surprising if the Dynafit turned out also to be as good at release safety.

But to be convincing for me, there ought to be specific differences in the designs or repeatably measurable test results.

Some years ago there was much concern with alpine downhill bindings about handling combinations of forces/torques—not just a forward fall, not just a twisting fall, but a forward twisting fall. So the downhill binding manufacturers worked on that, and claimed success. Then later there was more concern—and development of binding designs—to get better at releases for backward twisting falls.
I don’t recall proponents of Dynafit ever being interested in talking about this sort of thing. Then it’s interesting that I did not find any claim on the Fritschi website that the Diamir had any special capability for handling combination force/torque situations.

What I did see the Fritschi website website talking about was larger range of motion for forward-fall and twisting-fall force/torque without releasing the binding. It strikes that this is a good thing: temporarily “absorbing” a potential injury-causing torque without releasing.

Marker? if I really believe that weight on my feet isn’t critical, and release-safety is very important to me, why don’t I just use a Marker AT binding?
Simple answer is that the Marker alpine touring bindings were not available back when I was last seriously considering which binding to use.

davidof - 01 January 2010 11:44 PM

… Dynafit compatible bindings from ATK, Plum and Trabb. These are competition bindings with a fixed DIN 6 heel release.

To me the idea of removing release adjustment capability to save 100g or whatever seems stupid.

Seems to me the ski-rando race organizers should just change their rules to require that all racers use a binding that is not only releasable, but with an adjustment that meets some reasonable minimal standards. Race rules should be designed not to incent competitors to take risks which we already know how to manage without undue cost.

Ken

Oddly this is the first time on a forum or magazine article I’ve read someone just say that in plain English.

That is just my subjective opinon though skiing with Dynafit, Pures and Diamirs. When I have fallen the Dynafits only seem to release in the vertical plane at the rear whereas the other bindings will release at the toe. This is with the same DIN settings.

Regarding the weight thing Dynafit state a 1200 gramme difference between a pair of TLTs and a pair of Diamirs. That seems about right. They then claim this is a 6 tonne weight difference over 1000 meters. Now I’m trying to understand this figure, but I didn’t do mechanical engineering or applied maths beyond high school. Now 1.2kg over 1000m is, well 1.2kg, or 1.2 tonnes over 1 meter. Now with the diamirs you have the heel and bar to lift through about 30 degrees per step. Lets say 6 steps per meter rise. If the heel and bar weigh a kilo we are possibly lifting another kilogram in weight but I still don’t get the 6 tonne figure? Is it the old saw that a kilogramme on the foot is worth 3 kilogrammes in the backpack?

Anyone help me on this?

Can’t help if I don’t have a link to the full text (and context)—which a quick google did not reveal.

Sounds like it’s just some marketing slogan. If they want to make a serious argument, let them express their claim in terms of serious terms of the scientific discipline of physics, terms like work + energy in units of Joules, force in units of Newtons.

Clearly climbing 1000 meters with Diamir bindings can’t be like lifting 6 tons, because I can’t move 6 tonnes for even 1 meter, but I easily climbed on my Diamirs over 1800 vertical meters just yesterday. There may be something about Fritschi bindings that hinders me from winning a ski-rando race, but it surely does not stop me from skiing a big peak in a single day.

Anyway ...
1200g on my feet does matter. I’m sure I would climb a little bit faster with Dynafit instead of Fritschi bindings.
But for somebody who climbs on skis a lot and trains appropriately, it doesn’t matter much more than 1200g in my backpack.

I would also climb a litte bit faster if I didn’t carry a camera. Or a cell-phone. Or a SPOT satellite rescue beacon.

I guess lots of Dynafit users would say I’m foolish to carry a SPOT satellite rescue beacon, because I’ve never used it to send a message to a satellite to call for a rescue, and it surely makes me climb a little bit slower. (? maybe for 1000 meters it’s equivalent to carrying 3 tonnes

Ken