The Cyclist’s Eye on Skiing

A departure from the usual talk of pro cycling now the Winter Olympics are in full swing. As someone used to watching cyclists in competition there are many crossovers from the impressive VO2 max scores of the XC skiers to the importance of aerodynamics in downhill skiing.

But what of aerodynamics? Looking at the Alpine ski events there seem to be many things where the skiers could take time for free. Taking the screengrab above with Italy’s Verena Stuffer for illustration. The more you look, the more you see.

What goes for her seems common across the other men and women:

  • Many will notice the bib is creased. But they are given this and the International Ski Federation (FIS) rules say they cannot pin or modify it so let’s look elsewhere.
  • The suit is creased too, these lines interrupt the airflow and if the suit moves like this in the start hut it’ll do the same elsewhere
  • Look at the helmet. FIS rules reject spoilers and protrusions but could the shape be improved?
  • The holes in the helmet around the ears look odd given this is a competition event. The “drillium” might save a few grams but it’s so that users can hear what’s going on around them – useless in competition. They risk disrupting the airflow.
  • Look at the dangling chin strap, why can’t be it be cut to size to stop it flapping in the wind?
  • Personal style is important for many but long hair? Surely a hairpin or two could stop it flapping in the wind or those with very long hair can tuck it under their suit
  • Now for the goggles. Why is there a big elastic strap over the helmet, breaking the lines of the helmet? It’s also one of those adjustable ones with a double band and metal clip, can’t an Olympian get a piece of elastic to fit?
  • FIS rules don’t allow aerodynamic modifications to the goggles but could fit flush to the helmet to improve aerodynamics, no?
  • Look at the gloves, the second photo shows items that flare over the wrists like medieval gauntlets. Normally you’d expect something tighter to help with airflow. Maybe this flare helps spread the air around and over the arm?
  • We can go on, look at the pronounced bindings and the boots with their exposed ratchets from US skier Ted Ligety below (yes I know they’re open). But note the way the front of the bindings leave a gap to the boots and how there’s a big space between the sole of the boots and the ski, an empty space that just stirs up the air.

The Science Bit
Aerodynamics matters because air resistance increases to the square of the speed. In cycling we’re talking about competition speeds of 40-60km/h. In Alpine skiing it’s double with competitors clocking 130km/h at times meaning aero matters a lot more.

Cycling can be a very reductive sport. Climbing is all about the W/KG ratio just as time trialling is primarily a function of your frontal area and watts. By contrast a downhill skiing requires skill in picking the trajectory, power to hold the line and a lot of the tech goes into ski design and waxing to suit the conditions. In other words skiing seems to have a lot of variables.

Cyclists have learned plenty from skiers. We talk about tri bars when mentioning the handlebar prolongations but they’re really ski bars because they come from Boone Lennon, a ski coach.

I’ve checked the FIS rules and they don’t allow aero helmets but there’s little on big gloves, long hair or boot design to stop some gains. Of course downhill skiing needs huge skill and enormous strength and there’s a lot of danger, it’s so much more than a windtunnel session. But that’s the point, all the power and precision shouldn’t be held back by long hair or a flappy strap. See the winning margins in competition, the difference between gold and fourth place can be fractions of a second.

Aero perfection? No, look closely and his number is not stuck on properly

What if the skiers are right?
What if the cyclists are too obsessive? Your weeekend warrior dresses up in aerodynamic clothing for a Sunday spin and the market is flooded with aerodynamic products from the obvious wheels and frames down to aero pedals and other marginal improvements.

Commercial Imperatives
You can see two different commercial approaches. A consumer who wants to ape a pro cyclist can get all sorts of advantages but it’s impractical, specific and often marginal. By contrast the skiers are paid to wear gear that is sold to ordinary punters so boots have the kind of ratchets someone with frosty fingers inside thick gloves can adjust when sitting on a ski lift. Such a level of practicality isn’t needed this week but it’s what makes the market work.

And finally
It’s not just the Alpine skiing. Watching the snowboarders in halfpipe makes you wonder why they’re all in such baggy clothing. Sure it’s cool but oversized jackets = wind resistance = slower runs = less air. It’s a clear case of fashion beating performance and you wonder why some geek doesn’t slide down in a skinsuit.

None of this is meant as a criticism of fellow athletes, there’s no pretension of superiority. Cyclists and skiers have plenty in common and my trip down the Sochi downhill course would probably end in hospital rather than the finish line. Plus I’m skating on the thin ice of ignorance so feel free to put some informed comments below to correct this.

Skiers do work on their aerodynamics a lot, they visit windtunnels to work on their position as much as cyclists. Like cycling the governing body imposes plenty of rules so some obvious gains are outlawed. Yet the cyclist’s eye, rendered obsessive by years of science and marketing , makes you wonder why the skiers are giving up free speed, especially as the winning margins are so small. It can be cheap things like long hair or flapping straps, it can be technology like boots and bindings.

FIS rules 2013/2014 PDF

I put a similar piece as an afterthought on tumblr earlier in the week but didn’t get an answer so I thought I’d put it to a large audience again

61 thoughts on “The Cyclist’s Eye on Skiing”

  1. Funny how skinsuits were banned from downhill MTB.

    Speed skating as well is another where aero matters a lot and is akin to track cycling. The US team are presently hoping to change their suits for something more slippery.

    My colleagues have been involved in aerodynamics testing for skaters, although most of our work is with cyclists/triathletes.

    Pro cyclists are often not riding optimal aero kit either. The most aero helmet for instance varies by rider, yet when a team lines up for TTT every rider has same helmet. The differences are not insignificant either.

    • The suit changes didn’t help the US speed skaters very much. Another theory going around is that they only trained at altitude and that they now lack that bit of extra strength that is needed for the sea level skating rink of Sochi.

    • Pretty bad publicity for UnderArmour there, it seems like every one of them would drop their suit if the rules allowed. You have to wonder how the problem wasn’t picked up by testing. Apparently trialled in training but never in racing. Obviously I’m ignorant to the world of speed skating, but sacrificing aerodynamics for ventilation seems like the last thing you would want to do.

      • “Pretty bad publicity for UnderArmour there”

        but the “new” suits and the “old” suits that they switched back to were all made by UA; they were slow when they went back to the old suits as well. And the marginal gains provided by the suit (or any suit) doesn’t account for the US skaters being *that* much slower than the competition. The Dutch are just beating everyone (the Norwegians, Koreans, Russians, Canadians probably had similar medal ambitions, but they’re not complaining about suits).

  2. Regarding half pipe/slopestyle snowboarding – They are subjective, judged sports, and there’s a case to be made that baggy (or dark) clothing can hide missed grabs or other minor mistakes.

    While takeoff speed is important for both, most is lost due to poor execution of the previous trick (meaning you’re seriously penalised in scoring anyway) and riders often even check their speed.

  3. Interesting piece.

    I wonder where you draw the line though – for then it becomes about who has the best technology rather than who is the best athlete.

    Interestingly, why did they allow one ski slopestyle competitor to go down the run without poles?!? Couldn’t fathom that one….

  4. FIS regulates the permeability of the fabric in speed suits, but beyond that they do not give much attention to aerodynamics. The suits have fabric weaves that are oriented based on position on the body. Most of the fabric for the suits comes from one supplier, regardless of the brand on the suit itself, so there is little true variation between them. In speed (Downhill & Super-G), most athletes wear back protectors under their suits as well. About 15 years ago, Sypder added a wire bead to their suits, which was quickly banned, and not much has happened with speed suits since then

    Helmet spoilers and long tails are banned because the snow can catch the helmet and twist it, possibly breaking the athlete’s neck. Although these races are won by 100ths of a second, snow conditions and racer’s line, as well as ski preparation, can change so much over the race run that I think they have more of an impact on the speed than any aero aspect. That being said, of course aero is important, but alpine skiing has focused on line selection and turn shapes more than aero per se.

    As far as freetyle (half-pipe and slopestyle especially), and to an extent, ski jumping, baggy suits help control the speed. If your speed it too high it can make the jumps too big, and the athletes are very specific about what speed they need for each move. In jumping, too much speed can destroy the air pocket they ride down the hill- keep in mind that during the flight they are quite low to the ground and are using the ground effect cushion to add to flight.

    • More good explanations, thanks. I gather the suits all get approved on the day too with an official seal. On the risk of helmets twisting I was wondering about the elastic band of the goggles, this risks catching the snow with greater friction and twisting the head rather than a polished surface.

      I understand the importance of line and turn, wax and skis to some extent but it seems some “free” time is still being left out and by all, it’s not like some teams have a focus and others don’t.

      • The suits are tested during the race period, usually in the evenings after the team captain’s meetings. The test equipment is not practical on the hill. Tested suits get a badge punched through the leg cuff, and the start referee looks for them in the start area. As far as helmets twisting, I think the goggles pop off before they can create enough drag to affect the helmet. FIS bans GoPro cameras on racers for the same reason, but allows them on forerunners, so there may be more to it than is discussed in the open. Most of the speed skiers (DH/SG) do spend time in wind tunnels, but for tech skiers it does not make much sense. Tech has adopted speed suits, which are far better than padded wool sweaters and pants, but they don’t seem to pay too much attention to aero. I’m not really sure why skiers have not gotten more on the aero program, it may mean cycling has gone too far or skiing has not gone far enough. FWIW, Boone Lennon was one of the coaches on my ski team. I skied with him a bit, but he worked with older athletes when I was there. I did race with a pair of DH poles that he bent, but that was a disturbingly long time ago.

        • Re: goggles, helmets with inbuilt visors are available for consumers, is there a reason they aren’t used by racers?

          I think it would be fantastic if every racer had a camera and we could view the footage live during the racing. I noticed some racers have cameras in the snowboard cross event so I’m sure it’s possible.

          Cameras would be great for cycling coverage as well, perhaps more difficult logistically as you have to relay the signal to the broadcast centre hundreds of kms away. But a Cav’s eye view or handlebar cam of a finishing sprint would be amazing to watch.

          • I suspect you’ll see ski racers using the goggle cameras in the the next couple of years. Live footage may be an issue due to broadcast rights, but I suspect FIS will adjust their rules and regulations pretty soon. In that sense, they are much better than UCI at reacting to new technology. Ski dimensions, stack and boot heights, fencing, pole and panel regulations are written to protect athletes and are based on studies that can take years. Sometimes when I read about UCI equipment rules I am surprised they are allowing derailleurs. That being said, I have significant experience in ski racing and only ride bikes for pleasure, so I am not as involved in the details of the sport. I watch UCI like I watch House of Cards: for the pleasure of watching political trainwrecks.

    • Funny that you selected the photo of Brad at the London Olympics for this piece.

      The US ski clothing company Spyder designed and patented (Jacobs US6098198) a ski suit with aerodynamic trips. It greatly reduced the drag forces on a skier. The patent is good reading if you are into wind tunnel testing. My testing shows cylinder drag can be reduced by more than 35% if they are sized and placed properly. The suit was so successful when introduced that the FIS outlawed it and it went away.

      Now back to the photo of Brad and the British Cycling team kit. The UCI rules also forbid features that reduce aerodynamic drag. I’m sure Inrng can quote the exact paragraph. The UCI even sent a letter prior to the Olympics that they would be informing the rule.

      How can the UCI enforce the rules if they don’t know what they are looking at? It seems the UCI commissars didn’t know that those shiny strips on the arm and shoe covers are there for aerodynamic advantage. Maybe not blood doping, but the kind of cheating that reduces drag about 15-20 Watts at 30 mph. British Cycling, marginal gains or cheating at the margins?

      By the way, the ski companies also found that stretching on an undersized suit opes the face of the knit fabric and this allow more air to penetrate. Testing shows this is slower at skiing speeds.

  5. Nice article, I was wondering about the Helmets as that seemed the obvious one when I was watching the downhill the other day.
    With regards to Snowboarding, I think that there is definitely a perception of coolness and not trying too hard that the riders want to uphold. One only has to look at how Shaun White is perceived within the snowboarding community to learn that someone who really tries to win the Olympics is derided as too serious for what is traditionally a breakaway, more marginal sport than skiing.

  6. Great piece. I have often wondered why somebody competing in skier cross doesn’t just put a skin suit on and win. Or, a Kask or Uvex style face shield for the speed disciplines in skiing.

    • The skinsuit is banned for ski cross. In the first days of ski cross, some were racing with skinsuit but then, they agree to race in normal ski clothing. Also, the same for the helmet, the racers agrees to use free-style helmet with goggles. with the jump, too much speed could also be bad.

        • Not sure about the rule but I think the visor would need a good fit to avoid cold wind in the eyes. I can’t ski with sunglass but I am ok with cycling. I think I stil prefer goggles. And with a complete full face, you might have issue with fogging.

  7. The first question should be “what are we trying to test here?” I think it’s primarily (and should be) the SKILL at skiing of the competitor rather than the skill/expertise of the equipment suppliers. If all we’re interested in is the tech stuff, they could simply run dummies down the hill in various technical setups and easily declare a winner. I couldn’t help but giggle after hearing all the claptrap about the US speed skating suits designed by some military aviation contractors that are now being blamed (in part) for the team’s dismal showing. Way too much is made of advantages due to equipment – because nobody (yet) can make profits from the manufacture and retailing of SKILL.

      • Yeah, sure. I’m so tired of hearing how ol’ Laurent Fignon coulda/woulda/shoulda won that final time trial at LeTour if only he’d not had that pony-tail. And then there’s the 3-4 guys all coming to the line in whatever bike race you want to name…a couple with slab-sided “aero” wheels, one with box-section rims and another with something in-between. Funny how when it comes to the finale, who wins depends on (as usual) the legs rather than the bike or wheels. Someone who really cared could probably go back and categorize the female downhill ski results and compare the times of pony-tails vs none. I find it hard to believe there would be a significant difference. Isolating one aspect in this way is key to marketing products. Reminds me of the old joke about the guy who claimed to have improved the horsepower of his car 100%. His reasoning was he bought and installed 10 things that each promised a 10% hp increase!

  8. ” … Aerodynamics matters because air resistance increases to the square of the speed. … ”
    It gets even worse, because the *power* losses increase to the cube (3rd power) of speed.

    The power losses have to be supplied (almost entirely) from the potential energy of the skier’s elevation on the hill.

  9. No doubt you will be pleased to see that Anna Fenniger was wearing her hair today , in a bun ? Maria Reisch & Nicky Hosp , both have short hair and medalled for a second time ! These Medalists in the race today , had the Goggle frames tight to the helmet outline , so little chance of the strap being an impediment to airflow ?

    Having raced skis in the past , the only time i covered the ski boot closures was in a 24hr downhill competition . Then it was a matter of ensuring no moisture penetration rather than streamlining . Swapping the skis every 3 to 4 runs helped keep them running at an even pace but wearing a wind jacket in the middle of the night was noisy and was only of any value on the ski lift back to the start of the downhill run .

    In respect of the Speed skating , seems the Brit was disqualified for not ” Finishing in the Correct Manner” , perhaps some obscure rule , she was unaware of ?

    With the Snowboarding Clothing , i find it hard to understand why the viewer needs to know what underwear the Athlete is wearing ? Personally i would prefer to keep warm , with tight fitting outfits rather than having a draft up my back .

    Generally the Ski Racers , are users of bikes for Cross Training , so will be well aware of air flow . As far as the Austrian Team is concerned , they enjoy using Road race Bikes , so their reward for the Medals won in Sochi , will be to find themselves ” Hasselled off the roads ” , by the intimidating behaviour of Austrian Motorists , who insist on behaving as if Cyclists are unnecessary road furniture!

    • The speed skating ‘incident’ was that the Brit missed the end of the finish line by 1cm, so was deemed not to have finished (!) The line was checked & was to specification, so a big navigation lesson learned.

      Interesting how Oakley seems to have sewn up the speed skating market with their bulky design, when a head strap under the skinsuit would be more aero.

  10. I know next to nothing about skiing, but I’ve always been under the impression that like Formula 1 skiers want to have a specific amount of downward force to prevent them from taking off. Watching the downhill I noticed that a major factor for time less was getting to high at jumps. The skiers who stayed closer to the ground not only covered less distance, but also needed less time to regain perfect control after landing.

    • Yes, the skiers want to stay on the snow as it is faster than being in the air. Absorbing the jump or pre-jumping (a small jump before you get to the actual lip) are some of the techniques, you will also see some skiers tuck their arms against or behind their bodies in the air. I don’t think there is much of a Formula 1 aspect of air pushing down on the skier, they are usually concerned about cupping air in their chest and arms and being pushed backward.

  11. I was watching the speed skating the other day and the commentator was making a big deal of the skater’s aero boot covers, which seemed odd seeing as cycling TT’ers have been using the same (basic) tech for over ten years.

    Again with the speed skaters, the ones I watched today had boots that were open at the top and didn’t smoothly integrate with the athlete’s ankle – again, it looks gappy, messy and prone to creating drag.

    • I don’t put too much stock in the color commentary (especially) at the Olympics… often the commentators are not in touch with a given sport, and are looking for anything that may be of interest to the average viewer. I recently heard a commentator expound on how bicyclists are “starting to experiment with graphite bicycles”…

  12. Watching the ski jumping this evening and it was interesting to here the commentators discuss the rules on Body Mass Index, length of skis, allowed baggyness of clothing, etc.

    Basically ski jumpers want to be as light as possible, and create as much of a sail effect as possible when airborne. They want to be as non-aero as possible.

    The introduction of the BMI rule is to prevent the skiers starving themselves to a gold medal. It is akin to the UCI bringing in a rule relating riders height and weight to their allowed bike weight.

    Another aspect of ski jumping is that women in theory (having lower average weights and BMIs) could jump further than the men.

    • I heard recently as well that potentially women should be able to go further than men – which is great, given that this is the first olympics that women have been allowed to enter the ski jumping, and that there are a lot of countries (including Russia?) still against it because it’s “a man’s sport”.

      It was also argued that this could be the first sport where you don’t need 2 competitions but can allow men and women to compete together – which for my money would be great.

      • Historically, if women have started to get close to demonstrating superiority to men, their events have been changed to make direct comparison impossible. The Games have had a tough time shaking off that old-boy, aristocratic mindset in place at the time they were reborn.

        • “Historically, if women have started to get close to demonstrating superiority to men, their events have been changed to make direct comparison impossible”

          Which examples did you have in mind?

    • “Another aspect of ski jumping is that women in theory (having lower average weights and BMIs) could jump further than the men.”

      That would be especially interesting in ski flying events, where the explosivenes on the take-off is less of a factor and aerodynamics is everything.

  13. I have also noticed that the men’s competitors in ski jumping and snowboarding had their height and weight displayed. The women had only height. Why this silly aversion to sharing their weight with the public??

  14. Road Cycling and Cross-Country Skiing has also one common negative thing.

    Long deep history of doping.

    Both are long distance endurance sports where benifits of doping are great.
    Both have doping scandals (Festina, Lance vs Lahti 2001)

  15. Interesting piece; I liked the comparison of commercial priorities, obviously a consideration for snowboarders too.

    A Winter Olympics sport that is much closer to cycling – and not just in its approach to aerodynamics – would be long track speed skating. Similar speeds, similar endurance events, outside the Olympics even similar peloton tactics, and plenty if windtunnel testing

  16. Definitely some good points, particularly the exposed long hair and dangling chinstrap.

    I’m not sure how much can be done about the suit creasing; a downhill suit can only be made so thin before it gets too cold to ski in, and it seems like thicker materials will tend to bunch up like that, especially given the range of motion it has to accommodate.

    The goggles aren’t actually breaking the lines of the helmet as much as looks like; ski helmets have a recessed slot designed for the goggle strap to lie in. The adjustable strap does seem pretty unnecessary though.

    As far as the gloves, I have no idea if they’re more or less aerodynamic, but I would guess that much of the flare at the wrist is hard padding. Racing gloves are basically armored to absorb hits from gates, and if the padding prevents the potential distraction caused by a painful hit to the wrist then it’s worth the aerodynamic cost. Heck some racers will even wear plastic forearm protectors in Super-G (where the speeds often exceed 60 mph) because it allows them take tighter lines into gates to make up the aerodynamic disadvantage.

    Part of the difference between skiing and cycling in this aspect may be the culture differences. Many recreational cyclists look to the pros and try to emulate them, so if a company can design more aerodynamic equipment for the pros they can probably sell it to the public too. However, most recreational skiers don’t want to look like a pro racer, so there’s much less of a market for racing-specific gear.

  17. I have given up looking through the FIS site to check out the regulations. However, skiing, especially the speed disciplines (downhill, super GS, GS) have always had an eye on aerodynamics – remember those downhill skis with the hole in the tip? And the curved sticks that tuck in behind the body?
    It’s impossible not to be interested in the science if you are travelling at 130kph. But just look at the streamlined equipment used for speed sking, ( which is a kilometre in a straight line, and downhill, which is everything but a straight line – technique, skis, wax all play their part. Although many of the races are decided by split seconds, I think that, if everything else were equal, aerodynamics would be more important. You can see the amount of time a downhiller spends in the racing tuck, with everything in perfect position, and how much time they spend flailing around with arms and legs, trying to stay upright.
    But everything else is not equal, and a missed edge can mean a bigger loss of speed than a ponytail. Things are different on a bicycle, where you spend a lot of your time straight and level, tucked down on the drops, especially on the track, where the surface is smoother than the road – but nothing like the icy, bumpy, slippery surface in skiing.

    • FIS equipment regulations are actually buried in the marketing section of the rules. Along with rules regarding the size and placement of logos in World Cup (and a separate set of rules for Olympics), they address the permeability of speed suit fabrics. For speed skiing (as opposed to DH/SG) the suits are a hard rubbery material and are not legal in DH/SG as they are too slick in case of a fall. The fairings and wraparound helmets are also not legal. Manufacturers have played with dimples on the ski topsheets (like a golfball), holes in the tips have come and gone many times, and tip profiles have lowered. However, since none of these have lasted more than a season or two, it’s a safe bet they ended up not making a significant difference. Waxmen will tell you the bigger mystery is in the bases. They don’t know why one base will be fast in some conditions and slow in others, and they can only tell by testing each pair extensively. Each World Cup racer can have over 50 pairs of skis, each one tested for specific snow conditions.

  18. Some great discussion and insight here: I think later commentators may have hit the nail on the head – the aero marginal gains often completely offset by a bad turn or too high in the air.

  19. The idea in downhill is to stay on the snow, the points you make are valid but if aerodynamics influence skis having less contact with the snow turns may be compromised. “DOWNWARD FORCE”

  20. Interesting thread.
    In a nutshell – if it was faster and allowed, the skiers would be doing it. If they’re not doing it, it doesn’t matter or they’re not allowed. In my experience, winter sports are way more technical than cycling and have been for a long time.

  21. I think the downhill skiing events are more about technical skill than speed. I know they’re timed events, but the competitors can get all the speed they want (and more) simply by pointing their skis downhill. The skill in the event is controlling the speed through the course.

    • Well. It’s not about aerodynamics.
      It’s the curse of Finns against Swedes.
      Third was swede.

      In Lake Placid 1980 Juha Mieto (Fin) lost to Thomas Wassberg (Swe) by 0.01 seconds.
      Hum. Both had beard. Maybe Mieto’s was a little bit longer.

        • Finland was part of Sweden about 500 years. Then part of Russia about 100 years.
          After that no kings (there almost was one).

          Today that (almost bronze) guy Iivo Niskanen was part gold winning team
          in Men’s Team Sprint.

  22. so, an interesting one today that’s clearly had a change in rules- snowboard parallel giant slalom, which at the past three games has seen boarders in skinsuits. They’re now wearing baggy salopettes and jackets. Clearly going for style.

    • watching it, they’re still using the single ended boards with ski style boots and very high stack bindings- entirely unlike anything you’ll see recreational boarders using.

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