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Head i.Supershape Bevel

post #1 of 15
Thread Starter 
What are the side and base bevel on the Head i.Supershape?

Do certain skis work better with certain side cuts assuming that you are skiing the same way on two different skis, would one ski perform better with a 1/2, 3 and the other at 1, 3, for example? What should the bevels be on the Supershapes for mostly hardpack carving?

Thanks
post #2 of 15
In general, most folks find 1/3 to be a good compromise between solid edgehold and too much. I use it on all my skis, regardless of how they come from the factory.
post #3 of 15
I've been playing with base bevel, and have lately tried 0.5 and 1.0 degrees. My current thinking is that for general run of the mill non-racing everyday skiing 0.7 ought to be about right for the base bevel.
post #4 of 15
My SuperShapes are 0.5 base 3 edge.
post #5 of 15
I should have said that the base bevel is dependent on where you ski. If you ski more hard snow, you may want that a bit less. Sorry for not mentioning that...
post #6 of 15
I believe that a lower angle is generally used on SL than GS too. So if it has 0.5\3 on it now and your happy leave it at that.
post #7 of 15
I wrote up a FAQ (above) that discusses bevel and its effects on the ski and when the ski hooks up in the turn. Personally my new standard is .5 base and 3 side. I used to be a 1/3 guy, but the .5 hooks up faster and gives you a sharper edge... However, if you are sliding your skis at all (not carving) the .5 will make them feel grabby and cause the skis to jump around a lot on the snow. If you find them doing this you have a few options. One is to detune the tip and tail (which I don't recommend), or change your base bevel to a 1 degree versus the .5... Don't make the change unless you have to though.
Later
GREG

EDIT: I have moved this to the tuning section.
post #8 of 15
Quote:
Originally Posted by HeluvaSkier View Post
and gives you a sharper edge...
Do you know of any edge longevity experiments between like included angles?

Say, one at 0.5 the other at 1 or 1.5 base?
post #9 of 15
Quote:
Originally Posted by comprex View Post
Do you know of any edge longevity experiments between like included angles?

Say, one at 0.5 the other at 1 or 1.5 base?
1.5 base:. 1 seems too much to me on my WC SCs and that's what the factory put on 'em. 0.5 on my super-gs requires paying attention. It only seems like too small a bevel after getting used to the SCs.

If you decrease the base bevel you have to take material off the base, not so the other way around. That's one reason to make changes in small increments.
post #10 of 15
Quote:
Originally Posted by Ghost View Post
1.5 base:. 1 seems too much to me on my WC SCs and that's what the factory put on 'em.
1.5 base, at least one company 'standard'.

G, I was actually wondering more about whether the length of arc to roll onto the edge actually makes any bit of difference in keeping the edge sharp.

What happens to a knife edge if you sort of give it a bit of twist before starting the cut?
post #11 of 15
The Head's come from the factory with a 1 base 2 side edge. the Rep; here likes .5 or .7 base & 2 side edge.

All my other skis are .5,.7 or 1 & 3 , but 1 /2 on my '07 Head Worldcup i.SL RD VIST Race Stock Slalom Skis and they
skied absolutely fantastically!
post #12 of 15
Quote:
Originally Posted by comprex View Post
Do you know of any edge longevity experiments between like included angles?

Say, one at 0.5 the other at 1 or 1.5 base?
I have to admit that I have not done a lot of experiments on edge longevity. The main reason for that is that I usually tune my skis every time out or every other time out... so edge sharpness longevity is not exactly an issue. I have however skied Elan GSX's at .5, 1, and 1.5 degree base bevels. The 1.5 was great for headwall and steep courses skiing but literally sucked on anything that did not allow for high(ish) edge angles. The 1 was okay, but on a whim I switched to a .5 (when I got the most recent skis) and I have never looked back. They grip like cleavers with a .5 base bevel, and it takes literally nothing to get them on edge, turning, and gripping. All of my Nordicas are also a 3/.5 combo, and I have no reason to change them...

Your comment on how base edge bevel can effect radius (because you have to tip more with a higher base bevel) is very interesting to me. I have never really thought about it, but it does make sense. I have always looked at it in terms of a 1.5 base required that the edge would catch very late in the turn, load quickly and release. This almost unilaterally means that the skier is going to travel a straighter line for much longer than usual... meaning that the turn will be short and the radius will be forced to be smaller. I don't think this allows a skier to make tighter turns more easily - but rather forces them to do it.

I hope that addresses your question. Let me know if there is anything else.

Later

GREG
post #13 of 15
Quote:
Originally Posted by comprex View Post
Do you know of any edge longevity experiments between like included angles?
Personal Observations: With 12 and under athletes, we've generally moved to less side bevel - 2 degrees recommended. The compromise is to give us a couple extra runs per session with a sharper edge - yes the 3 deg or more on the side make skis razor, but they do dull much more quickly doing training reps on extremely hard snow - and, once dulled, alot more work to bring it back to razor - At 2 deg, they still hold great. For best performance, after each on snow session, re-hone the edges.
(Ski am, tune for pm)

For most free skiers, this is not an issue -

The amount of base bevel we recommend depends on the youngster's current level of awareness and accuracy. Set up at .5/3 with max lift under foot - it can get pretty tweeky (no forgiveness) for most.
post #14 of 15
Quote:
Originally Posted by whygimf View Post
Personal Observations: With 12 and under athletes, we've generally moved to less side bevel - 2 degrees recommended. The compromise is to give us a couple extra runs per session with a sharper edge - yes the 3 deg or more on the side make skis razor, but they do dull much more quickly doing training reps on extremely hard snow - and, once dulled, alot more work to bring it back to razor - At 2 deg, they still hold great. For best performance, after each on snow session, re-hone the edges.
(Ski am, tune for pm)

For most free skiers, this is not an issue -

The amount of base bevel we recommend depends on the youngster's current level of awareness and accuracy. Set up at .5/3 with max lift under foot - it can get pretty tweeky (no forgiveness) for most.
Ski doc, Mike DeSantis former Volkl product mangaer and World Cup Race director, who now is part owner of Precision Tuning Center in Framingham, MA says a 3 and 2 side bevel stay sharp. for an equal amount of time. He recommends a true 1 base and a 3 degree. side edge.

Mike's extensive background combined with 40 years in the sport of skiing, are instrumental to his success:

Graduate Stratton Mountain Ski Academy
University of Vermont Ski Team
Physical Education Degree UVM
9 years Alpine Coach at Stratton Mt. School
7 years World Cup Technician/Race Director for Volkl
4 years Product Development Manger for Volkl
Member Volkl International Test Team

I believe many folk over bevel their base edge, What they believe is a 1 degree is really closer to a 1.5 -2.
post #15 of 15
Quote:
Originally Posted by HeluvaSkier View Post
Your comment on how base edge bevel can effect radius (because you have to tip more with a higher base bevel) is very interesting to me. I have never really thought about it, but it does make sense. I have always looked at it in terms of a 1.5 base required that the edge would catch very late in the turn, load quickly and release. This almost unilaterally means that the skier is going to travel a straighter line for much longer than usual...
I would agree, for PSIMAN.

I see the turn shape as being more dependent on intent than on the net angle of the edge to the snow. In other words, in any real life situation it is impossible to keep the angular acceleration of the skier's knee to anything like a constant. So, given a greater base bevel, the skier would be required or tempted to accelerate the knee more within the same elapsed time and travel distance.

Notice then, that that also means greater deceleration of the knee to modulate the ski camber once the edge is engaged.

Is it possible, then, that 0.5 base allows a more delicate touch at the early part of the turn, partly because the deceleration of arrival is less?
Whygimf's last sentence sort of relates to this but I haven't worked out how yet.


As to Atomicman's concerns with inaccuracies. Certainly it is a problem. Especially with hand tools that only engage a file's width of an edge at any given time.

I posted this to DC ski some time ago, when I first started thinking about this problem:
Quote:
Let us consider the bottom of the core as a standard plane of reference. Ideally, the base should be of a given thickness relative to this. The edges are fastened directly to this plane. They are the hardest thing on the ski. They therefore provide the best guide short of sonar, magnetic resonance or other non-destructive probing of where exactly the core is under all that black plastic.

So, short of all those probing methods, a median height between the edges is assumed to be reasonably parallel to the core. We then set the edges relative to that median.

Could this be substantially off? I suppose it could, if one edge was -substantially- and -consistently- (tip to tail). higher than the other.

What, then, is the prime mechanism making sure neither we nor the shop unwittingly build in 1-3 degrees of cant (tilt in the roll plane), wreaking havoc on our knees and hips?

I don't know- haven't thought about it, or the similar problem of misaligned binding bridges for stone grinding.

I suspect that the answer is in the "consistently" part. Since all our tools deal with only a little section of ski length at a time, we are more likely to notice mistakes as apparent "twist" in the result.
EDIT: I am no longer convinced that the above base thickness/base grind error is the only possible source of consistent off-bevel.

Longevity: Just to clarify, my original question was whether there is any 'protection' from the base to a 1/3 as opposed to a .5/2.5 say. It relates to the acceleration/deceleration argument above.
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