Climbing Skin Science – 2016
Most important thing here, Tribometer friction measurements.
Last winter, Pomoca climbing skin company (owned by Salewa) teamed up with the Technology Centre for Ski and Alpine Sports (TSA) in Innsbruck, Austria to do some scientific skin testing. (I appreciated being invited, but did not attend, was burnt out on air travel after an epic winter of flying around, enjoying reliable modern airline companies.)
Most importantly in this, an attempt was made to standardize the “skier” by using a machine known as a Tribometer that glided the skin across a consistent snow surface, while measuring “tribological quantities” such as friction. Apparently, most Tribometers are small to medium size devices used, for example, to measure how well a seat cushion would prevent you from sliding off. The TSA tribometer is huge, a big long thing that shoots along a track — with a ski in tow.
Video below is the “rail” tribometer used by TSA for testing ski and skin friction. Embedded from Youtube.
We found this whole thing quite interesting, while limited in various ways the astute reader will no doubt infer.
The evaluated samples:
Race – Colltex – PDG
POMOCA – Race
Colltex – PDG Black
Contour – Race
POMOCA – Race Pro Grip
POMOCA- Race Pro 2.0
Mohair POMOCA – Climb Pro Mohair
Colltex – Extreme
Kohla – Evolution 100 % Mohair
Contour – Guide
Gecko – Standard
Mix G3 – Momix
POMOCA – Climb 2.0
Colltex – Mix
Montana – Montamix
Contour – Easy
BD – GlideLite Mohair Mix
Kohla – Peak MixMohair
POMOCA – Climb Pro S-Glide
Before we go farther, let’s mention the obvious problem areas here. Firstly, it’s too bad a skin company sponsored a test that included their own product. A non-profit alpine club or some other third party would have been much better. Secondly, no matter how hard these guys tried to test skins on a variety of snow types at a range of temperatures, they only evaluated a small slice of what’s possible in real life. Thirdly, manufacturing variations are a real part of climbing skin performance. For example, the actual batch of mohair (year, region etc.) can make a noticeable difference in the glide and grip of a skin sold under the same model name, color, and so forth. By that same token, I’ve seen the same model-brand of a nylon skin change from season to season. So let’s take this all with a grain of salt — yet give credit where credit is due as this is a noble effort to quantify what we’ve all experienced on our feet as the differences between climbing skins.
The boffins at TSA measured skins under the following constraints:
• Load of 7% bodyweight and speed of 2 m/s
• Load of 30% bodyweight and speed of 4 m/s
• Load of 100% bodyweight and speed of 2 m/s
Measurements above at temperatures of -2.5°C, -5°C and -20°C. The graphs reflecting the friction values of race, mohair and mix skins are given in Annex A.
Calculated friction energy expenditure per hour for skins tested at temperatures of -2°C, -5°C and -20°C
How much energy can glidey skins save you?
Mohair -5 .15 kg
They did a field test with humans that did not yield useful results. The human test (which you can do at home) involved sporting a standardized reference skin on one ski and a test skin on the other. I’d guess the problem with this is too many variables. Weight of skier, stride style, mental attitude, exact temperature and state of snow when the testing is performed, and more. According to a supplied press release “The direct comparisons with the reference skins have provided inconclusive results… As in all Lab tests the results are divided into the groups race, mohair and mix. Due to the variation of the reviews and partially very small differences between the skins, the statistics must be interpreted only as a rough estimate.”
Regarding the human testing, we feel it can be done but it’s time consuming. What you really have to do is evaluate one “test set” (meaning a reference skin on one foot and test skin on the other) over multiple days of ski touring in significantly different conditions. Even then, it’s only you not a large group doing the same test. A less than ideal situation. Now you know why, while we do a bit of such “A B” skin testing here at WildSnow, we don’t go crazy with it and draw dogmatic conclusions. What we usually do is evaluate weight (some skins are quite heavy), then simply make sure the skin has what we feel is good glide. We don’t worry too much about how skins climb. Worldwide, most ski tourers follow tracks designed for glide and efficiency. If you need grip, fine, just get some orange Ascensions or the new Voile offering (made of same fabric) and don’t look back as someone in the Wasatch might be gaining on you.
Race skin weights.
Mohair weights.
Weights, mixed nylon-mohair skins.
See more Wildsnow climbing skin content.
Now that you know what might glide the way you want, shop for climbing skins.
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Comments
24 Responses to “Climbing Skin Science – 2016”
Holy moly! Thanks, Lou!
What I’d really like to see is a comparison of static vs kinetic coefficients of friction in both directions.
What are the two colors in the ‘skin pull-off’ charts? Different temperatures?
Do you know how that test was done?
Do you know what differentiates “Race” skins from “Mohair”? Durability? Grip?
It seems like it’d make more sense to show each measurement for all skins at once, perhaps with an expanded vertical scale, rather than rescaling axes between market segments.
Were all of these tests on straight-cut skins of equal length?
(er, equal width and length)
Hi Charlie, race skins are just mohair skins optimized for glide. I’m assuming all skins were cut straight and equal length and width. Otherwise the results would be meaningless. Lou
Hi Lou, great to see the detailed results here and great to have the competitor rate our skins, both the contour race as well as the contour guide in 100% mohair so extremely well : )
Nevertheless I fully support your view on how relevant these results are for the average ski mountaineer (not very). We have been testing our products and new prototypes over the past years on the same tribometer a number of times but never found the results to be extremely valuable except when comparing the glide of a few different constructions or materials side to side. Furthermore, all materials that glide extremely well tend to either wear out quickly or climb worse than others. Skins that glide AND climb extremely well and are highly resistant to abrasion yet have to be developed…
But still, it’s great advertising for a small family-owned company like us…
Best regards,
Werner Koch
contour skins
Thanks for dropping by Werner!
Interesting article. Lots of data for something that, in the end, is pretty subjective and dependent on many things as Lou pointed out. I think the best testing is to compare skins in your “home” terrain and snow conditions. This at least gives a baseline for comparison between what a person usually uses on certain tours and conditions and whatever new skins they try.
Werner- I really like the Contour skins. I’ve been using a pr. of Hybrid Mixes I got last season here in Colorado in a variety of snow and temps. The glide is above average in every snow condition (BD Mohair Mix and CAMP mix being my baselines). Grip is also above average for mixes, and plenty adequate on all but the steepest, iciest skin tracks, on which only skins that don’t glide very well will grip better. I’m willing to give up a little grip in some situations for better glide in all situations. I have had a hard time with the skin sticking to the ski in cold temps, like 5 degrees F and below. Keeping them warm and dry in my jacket works on these days, but they do take a little attention in really cold temps. The tip and tail attachment are awesome. They are easy to peel apart when folded glue to glue, and easy to remove from the ski. These last two points seem to be the major frustrations with lots of other brands.
The pr. from last season does have spots where the glue is coming off the backing when the skins are folded glue to glue for any length of time. I don’t like using the sheets between laps, but always use them for over night storage or longer. Still, if I forget to use the sheets over night, the glue comes off the backing in small patches when peeled apart again. I contacted CAMP about this, and they said this delam problem is isolated to a small batch of hand made skins from last season. However, in our shop, we have demo skins from this season that also show signs of glue coming off. Not like the pr. from last season, but still a bit of a concern. These things are expensive in the US, and consumer expectations will be high. If Contour can figure out the glue delam issues, they will have a real winner. Thanks for trying to make skins better, and address common complaints with other skins.
A comparison of glue performance would be more useful, imo. But I’ve had the same make and model skins with glue that worked great, or totally failed, so I guess the same caveats apply re. manufacturing (or other) variations.
I agree with See…Pomoca should research glue some more.
To me, key points of a skin in purchase decisión are (in order of importance):
– compactability. How compact can I carry them on my pack.
– How much water it absorbs (more water = more weight and icing problems).
Waterproofness treatmentes, membranes, etc…
– weight (g/cm2).
– How well it glides.
To me, how much water they absorb can affect on energy saving more than differences in gliding between models.
Anyway, interesting data.
Thanks Lou.
I was just going over my notes from being in Europe last winter and doing some climbing skin research. A couple things I was told by industry insiders:
– Good skins with lots of glide and excellent glue are like road bike tires, they have a life span and need replacing fairly often if you use them much.
– All mohair climbing skin material is processed by only two companies.
– Mohair (goat hair) differs in glide and grip due to factors such as climate where the goat lives, what type of food the animal is fed, and where the hair is removed from the animal.
– Different batches of mohair skins, same brand and model, can vary in performance due to above.
– Presumably, 100% nylon skins can be more consistent, but here at WildSnow we’ve seen variations from year to year, probably due to “in line” manufacturing changes done deliberately, but perhaps inadvertent changes due to shifting manufacturing methods or locations.
Pablo, TSA did do water absorption testing. It’s such a small sample cross section, I didn’t think the results had much value, or did I include above and forgot (grin), have to say I was pretty overwhelmed at how to present all this info. Would have liked to do a better job of summarizing it. But too big a job for now.
If I have a moment I’ll look for the water absorption.
Regarding skin glue, there is a bar chart above for “pull off force.”
Lou
Dear Lou,
thanks for publishing this info and provoking the debate about skins performances.
As General Manager of POMOCA, I would like to add just some comments to all the interesting things that were said:
1) Yes, it’s a pitty that a skin brand has to organise this. I fully agree!! I would as well prefer a club of media group doing it (Werner probably as well!!), but the reality is that nobody is doing it, probably because of lack of interest. In ski test, for instance, brands don’t need ot do this. since media are interested in organising such kind of tests nd you can find plenty of them. I hope this will be so as well for the skins in the future. By now I hope that the reputation of TSA is enough to guarantee that Pomoca did not manilupate the results.
2) It’s a pitty that you could not attend the test. We were clearly insisting that, for us, it’s more important the approach than the results. Yes, they are some scientific data about skins for the frist time, and it’s really great, but I agree that they show a really small part of the reality. For us the cooperation with TSA is at a starting point, and what we see/know now it’s only a drop in all the ocean of “skins know-how” that could be developped in the future and nobody has. Tribiology (science of gliding) is very empiric (even for skibases) and in POMOCA we would like to know more to be able to have a more targeted R&D strategy. So: yes, we agree: the results are correct, but not highly significant in a global sense. But it’s a first step. And that was said several times during the test, and is as well valid for the on-snow test.
3) Greg: we did some tests on static friction (“grip”) but the TSA results were not significant enough. In glide you can scientifically confirm that “In this snow type, this humitity and this temperature, this skin glides x”. Even if it’s limited, it’s science. In grip we are making research to be able to give scientific data, but by now we did not suceed. Therefore TSA did not add those “grip” tests.
4) Charlie: difference between Race and Mohair is, as Lou said, the target user: Race are skins that glide faster, but normally have less durabilty and grip. TSA tested the race skins in parallel 62mm, and Mohair skins in trimmed version (all in Braod Peak 167cm skis). @Lou: not all Race skins are 100% Mohair. For instance Pomoca Race Pro is not 100% Mohair (… but we don’t say what’s inside 😉 ).
5) Pablo: water absortion test were done, but as well only a “initial” tests. The results are really difficult to read and apply. A 100% new skin is normally very water resistant. The problem is how the treatment hold on the hair after friction… By now it’s hard to make a significant test. The best is to use them, and check in average which skin glops the most…
6) Werner: yes,your skins are really good on glide! And this is not only said by TSA, but as well be users, which is more important. Congratulations.
7) @See: yes, glue perfomances would be good to test, but as well really hard! We do often “pealing” traction test in cold chambers, but then all skins perform quite well. The problem is when the skin is wet, the ski as well, how the user took care of the skin (keep it warm in the body or not, drying the ski or not,…),and good glue in the “lab test” can be really bad afterwards in the reality. But yes, we work on finding a way to compare glues and improving our glue ofr some markets (Pomoca glue works really well in the Alps).
Finally, I would like warmly thanks Lou for sharing the results (and for all what he does for skitouring!!!), for giving importance to skins and provoking the debate. In Pomoca we will keep working to improve the know how about skins and develop better products, beeing aware of our weakness and strength.
For further questions, don’t hesitate to contact me (josep.castellet@pomoca.com). I’m not that much checking the social / online media, but I read my mails daily :).
Thanks agains and best regards,
Josep Castellet
General Manager
POMOCA
Hey, I would just like to say, the warmth, open-mindedness, fair-mindedness, and general professionalism of Josep and Warner, from POMOCA and Contour respectively, in these posts, is really impressive. Much of the rest of the industry could really learn something from your approach–I respect what you guys are doing. For my next skins…I will try to buy POMOCA or Contour! All the best, and thanks for what you do. Bruno.
@Bruno: Thanks for the kudos.
@Josep: Thanks for your work and comments, well stated….
Nikwax ski skin proofer will keep your skins from wetting out, I think bd also makes a similar product but I haven’t tried it
The 1st time I tried it was for clumping issues, I put it on a wet skin and it worked awesume, usually I put it on once or twice a season at home the skin stays dry and I have no snow clumping issues
I still carry skin wax but never need to use it
Indeed, nice thread, thanks all! I wasn’t quite sure what to publish from the large amount of data, so ended up with a pretty massive blog post… but it’s all interesting IMHO… Love the secret sauce comment by Josep about the race skins having something other than mohair, silk (grin)? As I’ve written a number of times, I think climbing skins are one of the places there is massive room for improvement. So exciting times.
Wish I could have attended but it turned out to be wise that I did not. We ended up having a wonderful winter here in Colorado and it was nice to partake without breaking it up by another bout of overseas traveling. Perhaps next winter I’ll spend more time in Europe again and do more insider industry coverage. Every year is different that way.
Lou
A side note on weight: the Climb 2.0 are the lightest Pomoca skins in this test and appear to be the lightest overall. They are also the cheapest offering from Pomoca. This sounded contradictory to me, so I asked Josep about it. The unofficial explanation is that the Climb 2.0 use a low-density mohair and a thinner Safer Skin membrane (same membrane that is found in the Race skins).
You guys did a really nice project. Very interesting to also read all the comments. We at the FHTW in Vienna just did a similar project with climbing skins in-situ. We are also going to compare some of our results with yours. It is really hard and impossible to take into account all the different parameters influencing the measurement (like already said), but it is such an interesting topic and also the people/athletes are so curious. Thanks also again to POMOCA and contour for supporting us with skins!
This is awesome! Has anyone used the Ski Trab WC Skins? If so, can you comment on how these stack up based on anecdotal evidence?
While trimming Pomoca skins, I got the tail clip too short. How do I shorten it?
Sorry, I meant to ask, “How do I lengthen the tail clip on a Pomoca skin? I’ve worked on many different tail fixes, but this is a first time on the Pomoca.