Waxing your Skis and Exploiting the Wax Pocket

Sep 16

Grip Wax

Ken’s story

For a long time, I really thought that grip wax was only designed for gripping and that it would substantially drag the ski slower if it were allowed to come in contact with the snow during the glide phase of the stride. So I was very careful to keep my grip wax confined to a small section of the ski, and certainly never let it go beyond the edge of the "wax pocket". Lots of times I didn't get as good a grip as other people, and I thought it was because I didn't know the right tricks for my striding technique. Then I got a hint about it from an experienced participant on the rec. skiing.nordic newsgroup (Booker Bense, I think). Then I found it in an old out-of-print XC ski book at my parents' house. I think this "secret" is something everybody just knew back before waxless skis took over, so they forgot that some of us new folks trying waxable skis need to be told about it. So I'm telling. Now I've switched my approach to being careful to err on the side of putting wax over more of the base -- and lots of layers. And I'm much happier with my grip.

The magic of grip wax that also glides.

You might think that it's difficult enough just to invent a substance to make the ski base grip the cold snow at all. But grip wax, also called "kick wax" is much more clever than that.

After gripping the snow, it must also be able to "let go" and stop gripping the snow -- which can get tricky for new or loose snow.

Even beyond that, most grip wax is designed so that it can glide rather than grip -- if the ski is already moving on the surface of the snow. It grips only when the ski is stopped with pressure on the snow (static friction).

There is another kind of non-wax stuff called klister -- very sticky -- which often will not glide very well.

Grip wax glides better than waxless skis.

So if you enjoy getting long glide in each stride -- and you do a lot of your skiing in an area that typically gets below-freezing weather that is sustained for several weeks at a time -- then waxable skis are something to consider.

But glide wax does not grip (unless something is wrong).

And glide wax normally glides better than grip wax. But while glide wax is only for gliding, grip wax can be made to either glide or grip, depending on whether the ski is moving or stopped.

It is normal to be gliding partly on the grip wax during classic striding.

Even if the grip wax is applied only to the "wax pocket", it is normal for part of the wax pocket to be touching the snow during the glide phase of the stride. The result is that some of that grip wax gets rubbed off. But as long as there is not much pressure on the wax pocket, and the snow is not too icy or manmade, then not much wax rubs off very fast, so this is not a problem. While it is possible to design both ski and technique so no portion of the wax pocket would touch the snow during the glide phase, this requires precise and more-energy-consuming technique to get good grip -- so it's only of interest to racers. So if you want better grip, there is usually no harm in applying the grip wax over large portions of your ski base -- beyond just the "wax pocket".

The danger of putting wax over too much of the ski base is that it might "grab" the snow, and then carry icy chunks stuck to the bottom of the ski -- or worse yet send you flying forward onto your face. Some likely times for this danger is with new snow, especially when the temperature is near freezing, or the first day the sun hits powdery snow. If you carry with you a scraper and some glide wax, you can mostly undo the problem (provided you survived any forward fall) by scraping the grip wax off the "extra" sections of the base, and then rubbing glide wax over those "extra" sections. Otherwise, the main disadvantage is that the ski glides a bit slower than it would if the proportion of glide wax area were higher -- but that's a concern mostly for racers.

Exploiting the Wax Pocket

Ken’s Story

It's not that I ever consciously dis-believed that the wax pocket is centered near the toe. But neither did I ever believe it, or even think that question might have any useful implications. I just sort of figured I got grip by pressing my whole foot down on the ski. Seems like the obvious thing to do, the easiest and most natural thing to do. And I usually made sure I got lots of wax under the whole foot, and also some ahead and some behind it. When I got a pair of Fischer skis that had markings for the wax pocket, I did sort of notice that the markings extended out front of my foot a lot further than I had been thinking of it -- and they did not extend behind my boot like I had sometimes been waxing. But I didn't know exactly what the multiple markings meant, and I didn't see to how to put it all together conceptually. The beginning of the breakthrough for me was when Tomas Bystrom described on the rec.skiing.nordic discussion group a 3-step test for selecting the fit of a new pair of skis -- where the difference between the last two tests was whether the weight was on the whole foot, or only on the toe -- and clearly the toe-only approach was expected to compress the ski down more in the fit test. A while later it hit me that the same approach should work on snow, too. So I tested it out in my no-pole hill-climbing exercises, and it really worked for me. A few days later I tested the idea of pressing the toe even though my body weight was temporarily behind the wax pocket, not over it -- and that worked too. Which led me to the principle that the ski cannot "feel" where my body is at every moment: the only thing the ski feels directly is the distribution of forces and torques being transmitted through my boot and foot through the binding. Being sensitive to this allowed me to feel way more in control of my grip when climbing up hills. Then in big races I noticed that I was "out-kicking" lots of other competitors up hills -- and I couldn't help but think that was the key reason (since I don't have anywhere near as much waxing experience as most other racers).

What to Know

What is this "wax pocket"?

The wax pocket is a section of the ski base around the middle of the length of a Classic ski. This section has a special bend that tends to keep it a little further above the surface of the snow, or have a little less pressure against the snow, than the rest of the ski base.

The purpose of this special bend is that grip wax on this section will not get scraped off against the snow so quickly -- because it will not touch the snow as often while the ski is gliding, and if it does touch it will have less pressure on it.

How to find the wax pocket

Since the special bend is gradual, the boundary of the wax pocket may not be sharply defined.

But the true long-term test is simply to look at the ski after using it for long time, and ask "Where did the grip wax wear off quickly, and where did it stay on the base a long time?"

How is it used in applying grip wax?

The normal strategy for firm groomed snow is to put lots of grip wax on the central section of the base that is definitely inside the wax pocket, and to put only glide wax on the tip and tail sections which are definitely outside the wax pocket.

But waxing is much more entertaining that that . . .

How does the grip wax placement influence the degree of grip?

The degree of grip is determined by several factors:

(a) what percent of my body weight is committed to the ski I am currently pushing on.

(b) how much additional down-force I am adding (or up-force I am subtracting)

(d) where and how large is the section of the base with grip wax on it (rather than glide wax)

(e) how stiff is the ski

(f) what percentage of the total down-force is being applied to those sections of the base with grip-wax on them

The total down-force is given by the sum of (a) and (b). More total down-force implies more grip.

And clearly the more friction (c) from my selected grip wax, the more grip. This is the one lots of people focus on -- and you do not want to get the grip wax selection wrong -- but it's only one factor.

If I decide to put grip wax on a larger portion of the base (d), then other things being equal I will get better grip.

Stiffness (e) is actually one of the key drivers of (f), but the way to manage is different, so we mention it separately.

The last factor (f) sounds plausible, but perhaps it is a bit tricky. It says that I ought to try to steer more of my total down-force away from the glide-wax sections of my ski base and toward the grip-wax section . . .

What controls this shifting of the force percentage from glide wax to grip wax?

(1) what ski I'm on: stiff versus soft

Stiffer skis tend to put a larger percentage of the force onto the tips and tails, which is where the glide zone is, not the grip zone.

One simple way to get better grip is to use softer skis -- since they allow more force to go to the center zone of the ski where the grip zone is.

With waxable skis, there is way to help compensate for stiffness

(2) what snow I'm on: hard versus soft

Softer snow especially calls for softer skis. Your skis might be OK for firm snow, but a bit stiff for soft snow.

That's because less of the center section of the ski base reaches the snow once the tip of the ski has has packed it down or "shoveled" it out of the way.

With waxable skis, there is way to help compensate for soft snow -- see Using Grip Wax.

Some people actually have two pairs of Classic skis: a soft-flex pair for soft snow and a stiff pair for hard snow. It is much more fun to use a soft-flex ski on hard snow than a stiff ski on soft snow: Therefore it is highly recommended to buy your first pair soft. If you find later that your grip wax rubs off too quickly on hard snow, or you get serious about racing, you can then buy a stiffer pair.

(3) where I focus my pressure through my boot

This works for most Classic skis -- at least for all of mine.

But before going any further, check it out for your skis:

If you got the same paper-move range for all three weight-distributions, then you've got evidence that the force percentage on the wax pocket is determined by the ski design -- so the techniques on this page will likely not help you with this ski.

If you got the smallest paper-move range with weight focused on the heel, then you've got some unusual skis -- so the techniques on this page will likely not help you control grip versus glide with this ski.

If you found that weight focused on the heel showed the largest paper-move range, and that weight focused on the toe (or "ball") showed the smallest paper-move range (or a tie for smallest) -- then you've got good evidence that weight focused on the toe puts the largest percentage of weight on force on the wax pocket and grip zone for the ski. That's what I do when I need more grip, and it definitely helps. My "secret" control buttons: Press the toe for better grip. Press the heel for better glide.

What to Do

I can get a little better grip any time just by pressing my toe.

(Works for my skis -- see if your classic skis show the "normal" results from the measurements described above.)

Actually I think I also press the "ball" of my foot.

The "ball" is the slightly rounded section of the inside and bottom of the foot, at the joints where the individual toes connect with the larger foot. It is rather difficult to press with tips of the toes without also pressing the "ball" of the foot -- a bit like ballet dancers going up "on point".

It was Parham drew my attention to this use of the "ball" -- indeed his advice for getting grip up hills is to "dig in with the ball of the foot". But my mental image is only of the toe -- I leave it to my muscles to know how to interpret that image in a way that's most effective for them.

But this takes work, and it's not the most important way to get grip. I use other grip "tricks" too.

The main way to get grip is complete and uninterrupted weight transfer to the ski I'm currently pushing on

It's easier to press my toe if my body weight is leaning forward.

And to sustain the toe-pressure over time, getting my weight forward is required (since otherwise my body weight would soon have to fall back onto my heel).

On gentle-to-moderate terrain, many elite racers "fall forward" just before starting the leg-push.

But forward body weight is not always required: The ski cannot "feel" where my upper body is.

Basic physics says that the ski can only "feel" the pressure coming through the bottom of my boot and binding. So it is possible to get (temporarily) the improved-grip benefit of pressing my toe even if my body weight is centered back behind the foot.

One situation where this can be a useful option is when climbing up a steep hill, where elite racers often "reach" their new foot way up the hill, and temporarily need to hold their grip even before their upper body gets "caught up" again over the new foot.

My advice:

Don't just follow somebody else's theory, and don't just rely on dry-land observations -- actually test this for yourself on snow.

Find a set track that starts gentle and gradually gets steeper.

With skis on -- and without using poles to help:

try walking up it with weight on heels and see how steep you can go.
try walking up it with weight on toes and see how steep you can go.
find out how steep you can hold with all your weight through the toe of one ski.
staying in the same place, change the focus of force to your heel, and see if you slip back.

Remember: No poles to help -- Play with ideas for how to get the most out of your grip wax. And make it so that not just your mind knows what works best, but your feet have felt it for themselves.

try going up a hill using no poles, and play with different combinations of (a) pressing heel versus toe; (b) ankle always flexed and underneath you versus reaching your leg up the hill; (c) upper body erect versus leaning way forward.

I find that I usually get better glide by pressing my heel.

Pressing my heel -- during the glide phase of course -- will normally result in more pressure to the snow through the tail section of my ski (where I put glide wax), and less on the wax pocket (where I put grip wax).

That's why if I decide to wax "long" outside the wax pocket, I usually extend my grip wax zone only toward the tip of the ski, not the tail. So I still retain "pressure through the tail" as my consistent "control lever" for more glide.

Since pressing my heel normally takes some of the pressure off the grip wax zone, doing it during the gliding phase has the added benefit of keeping less grip wax from getting rubbed off from my ski base. So my grip wax keeps working for a longer distance before I need to put on more wax.

So the pressure focus through the foot (toe versus center versus heel) could be different during different phases of the stride: Press my heel during the glide phase, then press my toe (and "fall forward") at the initiation of my next leg-push.

Then there could be a third distinct phase after that, with a mental image of "keep the heel down" through to the finish of the leg-push. (Does this mental image contradict "press the toe"?

Bending forward a lot can strain your back.

So you're asking for trouble if on one day you greatly increase the amount of time you lean forward, the number of times you lean forward, and/or how far you lean forward.

Leaning forward works, but you have to train your back carefully for it, build it up slowly over several weeks and even months.

jocelyn belena