A bevel base challenge

You do not bevel the base. You bevel the base edge.

This fact pretty much nixes your ridiculous question. If you have ever skied a shape ski with no base "edge" bevel, you would not be posting such a ludicrous challenge. You would know the answer as I do.

But to you challange as wriiten. No! Yyou do not bevel the base!

Now for the answer to the challaenge i believe you may have been trying to propose.

Shaped skis without base "edge' bevel cannot be carved progressively. You are either on edge or off edge with absolutly no forgivness in the transion engaging the edge or realesing the edge.

since skiing technique has changed dramatically with the advent of shape skis and skis that are longitudinally forgving but torsionally stiff, one no longer needs to use extreme up/down movement to engage the ski like in the old days.

We can now merely roll your feet and knees over and progressively ski a clean carved arc. this mrequires some level of space between the base edge and the snow so that the result of rolling onto or off of edge is not extremely abrupt. This is why it is even more important for most recreational skiers ot ahve base edge bevel. it is extremely technically demanding to ski a shape ski without it. most recreational skiers would struggle tremendously with no base edge bevel.

Contrary to your thought process about the only skiers that ski with -0- base edge bevel are World Cup slalom racers who have technical ability far and way above almost all recreational skiers and are skiing on water injected and frozen race courses the likes of which few of us have ever skied on. they are making extreme turns in slalom and in many cases require the complelety on or completely off perfrormance that no base edge bevel provides.

I have tried 0 .5 .7 and 1 degree base bevels.

for the majority of recreational skiers a clean true 1 degree is going to work best.

there are many of us here that prefer a .5 or a .7. And the differenc eis startling.

0 base bevel is almost unskiable on hard snow and at best extremely unpredictable with no room between on edge or off edge.

I'll help,

You don't believe base bevel is important, your location is Stowe... I work in a shop in Stowe. I'll tune your skis completely flat, you tell US what you think!

I think he meant a grove in the centre of the ski like so


(try clicking on the pic for a slightly larger pic where the centre groove is more visible.

Oooo, Liamski take that challenge. I'd be very interested in the results. I ski most of my skis flat and have a couple pair w/1* base bevel. I think both work fine but I do prefer flat. Not much sidecut though..... and I'm not a very good skier so what do I know To me 1* seems sort of like driving a car with a bit of 'play' in the steering wheel.

What. He thinks that argument was settled!

The Groove works! All skis should have a groove, unless you spend all your time turning.

As for the the base bevel. I didn't take any data, but I have experimented with changeing base bevel, and believe me recreatinal skiers are better off with a base bevel of at least 0.5 degrees, and probably 1.0 is best for most sub-advanced skiers.

I knew what he was talking about.

gotta love it!

Yup. You knew right away. I just couldn't wrap my head around the fact that anyone could question the utility of having a base bevel on their skis. It's been too long since I've been in the land of soft and deep snow. I eventually figured it out though, but by then it was too late.

I have never experimented with different base bevels, but I have always found it hard to believe that such subtle angles are noticable. Heck, it is hard to even measure the angles -- it takes a lot of practice to get better than 1 degree accuracy with a true bar. After all, snow is not completely flat -- it has grains and clumps and so on. For ice skates on newly Zambonied ice? Sure.
For snow?

There are plenty of people here that I find credible based on long-term posting history who say 1/2 or even 1/4 degree is noticable, so I guess I sort of have to accept their testimony, but I don't understand it.

I think he was referring to the "tracking groove". It was a carry-over from nordic skis. Waxable classic-stride XC skis still have this.

As far as base edge bevel - I used to really worry about it 20 years ago when I raced. Now I have absolutely no idea whatsoever what the bevels are on any of my skis. Then again all I have are a bunch of fat skis. Once in a while I hold the ski in one hand with the tail on the floor and run a panzar file down the side edges.

I can not fathom how anyone can tell the difference of one or two degrees of angle on a 1/4 inch wide surface in the typically uneven packed snow found at most US resorts.
There are two surfaces involved, the ski and the snow. We're splitting hairs on one and have zero control of the other. If it were a smooth skating rink ice I might notice a difference but on packed snow I just do not think it is possible to be that precise.
Think of sharpening a knife. Within the "normal" range, an edge is an edge is an edge. A chef does not worry about 1 degree plus or minus. I think the sharpness of the edge is a function of smoothness not an odd degree of bevel.

What you say makes perfect sense, but I have skied the same skis with the bevels changed by 1/2 a degree and it made a very noticeable difference.

The proof of the pudding is in the tasting.

Maybe the change is going past some critical angle (maybe .666 degrees or maybe ski dependent) where things suddenly let go.

Sorry, no study. There is no study to prove that Kittens will drown if thrown in a deep lake while trapped with rocks in a burlap bag either.

However I can remember the flat Earth Issue.
Around 250 BC, Eratosthenes calculated the circumference of Earth. Back then everyone knew that Earth was curved. Today there is still a flat Earth society today that thinks Earth is flat. I guess they can't see the horizon.

Anyone who has studied physics to a high degree can tell you that whether your system uses one point as fixed or another point as fixed makes no difference to the situation; it only simplifies the math. I guess at one time symbolism was more important than simplicity.

Like my dad, I plug my car in when it's cold.

From my non-blind study i can tell your there is no difference when turning other than the added edge grip from a more acute angle, but when side-slipping or spinning around to ski backwards while you watch someone you are teaching or otherwise skiing sideways on a flat ski there is very big difference. The tendency of the ski to feel locked in as if on rails is also more noticeable on skis with less base bevel, if the ski has a relatively long turn radius.

Do you need this reference for a peer-reviewed article? 100 bucks isn't much, but if you supply the skis, I'll give you a ski day for the lift tick.

If you're skiing on six inches of fresh, edge tune is irrelevant.

No detuning in my experiment. All skis razor sharp tip to tail.
Base Bevels explored. 0, 0.5, 1.0 degrees.

You forgot to attach the double blind study to support this "hearsay".

Try first.
Much less than 1/4 inch, much less than 1 degree. Your failure to "fathom" isn't relevant. Lots of people fail to fathom all sorts of physical realities, especially relating to processes at scales they can't readily see. Try first, then fathom.
Transform I'd love to see a paper on:


Transform frame such that the road is stationary and the airmass is moving. Perhaps after writing equations of motions for the treadmill example.

(way, way more fun than airplanes on mental treadmills)
In the blind testing that is the industry demo, I'm capable of skiing on models of skis I've never skied on before and still identifying tune faults with fairly decent accuracy. I bet it is less than .90 confidence in the specific fault I'd note and much worse as to exact bevel on ski, but here we are talking about a wide range of skis and dozens of variables. I've not recorded my performance in this matter. Pay for my airfare to the EWSRA on snow at Stratton this year and I'll demonstrate for you; you do the math and metrology, I do the skiing. Alternately, you can find a rental shop and have them tune up a hundred pair to your specs, and I'll get to work letting you know how each ski is tuned. With the "right" snow, I'm confident I could give you good results. I get this confidence from experience with the topic, not lore or faith or whatever.

There are people far more experienced and capable than me that would be better choices for this work, it should be noted.

I'm not sure why it is so surprising that small changes in ski geometry significantly change the ski behavior. The snow-ski interface (on sufficiently hard snow) takes place in small regions of a complex pseudoplastic material subjected to locally high pressures, strains, and changes of state. As others have noted, as the snow becomes sufficiently soft and loose, edge condition and shape stops mattering.

It is worth noting that changes in a system that we can't confidently identify aren't necessarily pointless in a complex system. The race car driver may not be able to identify blindly a half/quarter psi difference in tire pressure (there is enough variability in tires from even the same batch that the pressure difference might be overshadowed by other factors) but this doesn't mean it is useless for the driver to ask the engineer for a half psi less on the next stop as part of a strategy to push dynamics in one direction or another.

Neat trick with the prop. Notice he has to hold it in place until the prop is up to speed.

A simple translation would work. The interesting bit to me is the shape of the prop. (homolugus series and all that stuff). I'm amazed that plane props used to be hand carved out of wood. Boat props also fascinating.

I want a double blind study that shows fat skis have move float than skinny skis. Until you present the study, I won't believe you.

I'm still giggling over in the same sentence as .


BTW, Garrett, there is supposedly a 19th century french proof that iceboats given a long enough lake and a steady headwind with low runner friction can approach the speed of light; I haven't seen it yet.

Given an arbitrarily long treadmill, what would happen if you set the cart on at rest and then brought the treadmill up to speed? As the torque on the prop from the relative wind turns the shaft (connected by gear to the wheels) does the device eventually accelerate beyond the speed of the treadmill and pass the starting point, or does something else happen? Translating this to a long stationary road with a steady wind from directly behind the stationary cart, does the cart eventually travel faster than the wind directly downwind?

I agree that props are in general fascinating. Handmade wood propellers are still popular in experimental aviation. Boat props add intrigue by operating with multiple phases of matter such as in supercavitating props.

edit: comprex, I've seen reference made to the iceboats but haven't seen any discussion or this proof you speak of. something to put the google-fu on when I'm sufficiently bored.

this is probably as close as you will get to a real world test.


Base Bevel – the "Heart & Soul"
By Dave Peszek

This is the second in a series of articles on ski and snowboard tuning that will appear this season in Ski Racing. Each issue, we'll tackle different topics that arise in the preparation and maintenance of alpine and nordic skis and snowboards. The author will attempt to answer any tech questions that you may have – Pez@holmenkol.us.

If you have been following along, in the last issue we discussed the importance of starting the season off with a well cleaned & waxed quiver of skis. This issue, we will dive right into what a good friend calls the "heart & soul" of a ski – base bevel.
Graham Lonetto, owner of Edgewise Elite Service in Stowe, VT & former WC women’s technician, has studied the interplay between base bevel, slope pitch, and time through a GS training course. "One of my athletes was skiing fast on steep pitches but loosing time on the flats, so we did quite a bit of testing with base bevel. We found that increasing the base bevel allowed the athlete to be less harsh on her edges. This allowed the athlete to let the skis run downhill rather than across the pitch, drawing out the turn" says Lonetto. The testing consisted of equally prepared GS skis and considered angles of one half, three quarters, and one degree of base bevel of the athlete’s GS skis. This leads us to the statement that base bevel is the "heart & soul" of the ski. Small changes in the bevel contribute drastically to the skis on snow feel, performance, and ski-ability. (Bold Underline added)

The important thing to learn from Graham’s testing & WC experience is that base bevel is a hugely important variable, but also one that is subjective to you & your particular equipment setup. Change any one factor and they all are affected.
Virtually every ski today comes from the factory with a high quality stone grind, and often the base edge is "relieved" from the base material. This is a description for a factory process where the base steel is made roughly parallel to the base material, but set very slightly below the level of the plastic. When you, your coach, or your favorite shop inspect the factory base bevel, be sure to determine if the base side steel is actually angled (and how much) or if it is relieved.
One way to check your base bevel is to lay your true bar across the ski and carefully hold the bar flush against one base edge, testing in several spots along both edges of the ski. If you can lay the true bar flush against the steel, you have a base angle. Does the true bar just touch the corner of the steel & the base material? If so, you have base edge relief. Now examine the gap that is present on the other side of the true bar. Measure this gap in several places along the length of the ski. Ideally, it is consistent throughout the ski’s length. I like to see between 1-2 mm of consistent gap under the true bar – of course this is personal, and you need to test yourself to decide what is best. I also like to use an old gap dwelling tool or valve clearance guide to measure this distance (bonus points if you have one lying around!).
Many athletes will choose to start at one half degree and test from there. Remember, it is always easier to increase base bevel angle. Decreasing the angle requires extensive, precise, and very skilled stone grinding. Be sure to set every ski you own for that given discipline at the same angle, and check for consistency of angle throughout the season.
As far as the actual technique of applying the base bevel, just follow a few simple guidelines:
• Cleanliness is godliness – keep all the filings away from the ski using an inexpensive paintbrush.
• Always pull the file so that the filings are ejected away from the base material not into it. If you are right handed, that means the tip pointing towards your left and file the furthest edge, then flip the ski and place the tail towards your left and file the furthest edge away from you.
• Use the sharpest, smallest, straightest file you have. I ALWAYS check my files with a true bar before using them. Especially check the file for "tail", which is when you have a nice straight file but the last centimeter or two veers off course. If this happens, don’t be afraid to break that section off. For base beveling, I like to use the finest file I can, and choose one that has very shallow tooth height. This yields a more precise cut and the file cuts less with each pass, allowing for more accuracy.
• Use only high quality files made specifically for ski tuning. The files from the corner hardware store definitely won’t do the job here.
• Watch carefully to ensure that file is not cutting the base material.
• Hold the file and file guide precisely. Press straight down, with gentle to moderate pressure (don’t bend the file). Let the sharp file do the work.
• Pull in long, smooth, overlapping strokes. Count your strokes so that you pull the same number at the tip, middle, and tail, on both sides, and on both skis. Brush the file & ski clean after each pull using your paintbrush.
• Polish the base steel with a hard Arkansas or ceramic type stone.
Next issue, we will tackle shaping the ski.
Remember, the race to win starts now!
Dave Peszek is the brand manager for Holmenkol USA, and a member of the Holmenkol World Racing Team. Dave also handles World Cup race service for Holmenkol and Uvex. "Pez" can be reached at Pez@Holmenkol.us and will try to answer all of your technical questions.

You are either showing your complete ignorance on the subject or you simply ski down the hill in a controlled (maybe uncontrolled) skid

Your post is preposterous as is Liam's entire premise.

Should i believe you guys or the skis on my feet.

Can you guys even ski worth a S_ _ _?

This thread should be read only for gapers!

of course you don't need base bevel you need Flaps and an altimeter!

Base bevel has no effect in the air!

I think you're a decade early there.

He doesn't believe in base bevel, but he has a time machine? Go Figure