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.5 & 3 vs 1 & 3?

post #1 of 27
Thread Starter 

I'm talking of course about base-edge and side-edge angles in degrees respectively.

 

What would be the difference in performance and feel?

 

Pros and Cons?

 

(FWIW, I guess it would be easier to go from .5 and 3 to 1 & 3 than the other way around.)

 

Skis in question would be high performance front-side hard-snow carvers.

 

Thanks!

post #2 of 27

The main difference is in on-center feel.  It's a lot like the steering wheel of a car that is designed to have a little "play" when you turn it a bit before the wheels actually turn (1-3), versus one that turns the wheels sooner when you start turning the steering wheel (0.5-3). 

 

Also the 0.5-3 will be 0.5 degrees more acute, causing a slightly better grip on ice.

 

The above technical difference manifest them selves by making the 0.5-3 far better for carving turns arc-2-arc, and making the 1-3 easier to feather the edge when skiing sideways.   For mogul skiing I would recommend a 1-3, or even a 1-2 if the moguls are not icy.  For carving outside of moguls I would recommend a 0.5-3.  For deep snow it doesn't really matter that much.

post #3 of 27

The other advantage of .5/3 is that you can turn it into 1/3 without re-grinding. So you might want to try it and you can soften it if you don't like it.

post #4 of 27

I went to 0.5/3 on both of my front-side carvers, which I also use in moguls (170 cm Mya 7's and 170 cm iSuperShapes, both 66 mm at the waist), and found this worked fine.  I was concerned the skis might become overly reactive, but I didn't experience that.  And, as epic says, if you don't like it you can easily adjust to 1/3 w/o regrinding (though if you do this you might want to wait until your edges become dinged up, since you can reduce the dings in the course of increasing the base bevel; and if you decide to increase the base bevel to 1.0, be very careful -- it's easy to go over that)

post #5 of 27
Thread Starter 

Thanks guys - I'm going to give .5 and 3 a try - I'll let you know how I like it in about 5 weeks!

post #6 of 27

I've tried .75° on the base that was feathered to 1° toward the tips & tails.  I liked that a lot.  Reducing the angle requires that the base material be thinned to get the lower surface of the edge down to the required angle.  The base material is one aspect of the life of the ski.  But, if you do it, it is easy to increase the angle by hand to .75° or 1° to get the angle that works best for you.

 

 

 

(The ° symbol is made by holding the Alt key and striking the 0176 keys.)

post #7 of 27
Quote:
Originally Posted by SoftSnowGuy View Post
 

 Reducing the angle requires that the base material be thinned to get the lower surface of the edge down to the required angle.  The base material is one aspect of the life of the ski.  

Do you know how much they actually remove in practice?  At least in theory, to go from 1° to 0.5°, you only need grind the base until half the edge-width is flat, which requires removing only 10 microns (1/5 the diameter of a human hair!).   And even if they need to get to completely flat as a starting point, that's just 20 microns.  Either seems like a relatively small loss.  But how much is lost in practice, with a skilled tech?

post #8 of 27
 
Originally Posted by SoftSnowGuy View Post
 

I've tried .75° on the base that was feathered to 1° toward the tips & tails.  I liked that a lot.

 
Yes, also a good option.  I know of someone that did 0.5 -> 1.0 on his bases and liked it.  I suppose if the OP would like to experiment, he should start with a straight 0.5, and if that's too reactive add a variable bevel (0.5 -> 1.0), and if that's too reactive go to a straight 1.0 bevel.  [Not sure if you can go from a straight 0.5 to a variable 0.5 ->1.0 in practice, though -- he'd need to talk to the tech.]
post #9 of 27
Thread Starter 

OP here.

 

They're 2015 Progressor 900s. This is their 1st pro tune. I skied them straight out of the wrapper for 10 days last season.

I told the shop - SKIMD Summit Ski and Snowboard in Framingham MA, the best ski tuners I know - to go ahead with .05 and 3.

That was their recommendation, even though Fischer's factory tune is supposedly 1 and 3.

If I don't like it (but I think I will), I'll go back to 1 and 3 next time, which is what I had on my old Atomic BetaRace 920's.

 

Thanks again!

post #10 of 27
Mikes done my skis to that stating and you'll love it. I have it on my race skis and all mountain. Use those skis in the bumps as well.

It might take a couple runs to get used to it but once you do, you won't look back.
post #11 of 27

A lot of how you will like one vs the other has to do with the snow you ski on and how you ski. 0.5 responds quickly and is useful for racing where performance counts. 1.0 is less touchy and a lot more forgiving for recreational skiing when you just want to cruise. Softer snow is going to be less affected by base bevel whereas hard snow and ice will accentuate the characteristics of the bevel.

 

I was surprised (as a new shop tech) to learn how much (actually how little) is taken off with a good base grind. A bad, aggressive grind can take a lot of life from the base, so you have to be careful who you go to and trust they will do you right.

post #12 of 27
Thread Starter 

Finaly got to ski them today on - what else - frozen granular.

I liked it - didn't find them overly reactive at all, just more precise - but I think what made me like the tune was more that the bases are now really flat than anything else.

post #13 of 27

Funny that no one mentioned cost. If you have someone else do the tuning, .5 needs sharpening a lot sooner than 1. So that $30-$50 happens every week or two instead of every month or so. And if you try to stretch it out, you might well end u with a dull .5 that's inferior to a moderately sharp 1.

post #14 of 27

Why would a .5 base need more sharpening? I've never noticed a need for that.

post #15 of 27
If you buy into a 3° side needing more sharpening than a 2°, then the .5° base would possibly need more than a 1° base, but only half as bad. But most here don't buy the first scenario, so the second scenario is even more iffy.
post #16 of 27

That's interesting...

 

I have old fischer progressor 8+ 2010s which are 1 base 3 edge as their factory settings. However the local shop has set them to 2 edge 0.5 through to 0.75 in the tip and tail, on their Montana radial tune equipment.
They gave me the same theory you mentioned that since 3 is a sharper edge than 2, it'll blunt sooner and need sharpening more often. I wasn't sure on this but took their word for it.


Does 3 not blunt quicker than 2? Anyone got some background info on that?

post #17 of 27

I have not noticed any difference, but my different edges are on different skis, so no data other than anecdotal.

post #18 of 27
Thread Starter 
Quote:
Originally Posted by beyond View Post
 

Funny that no one mentioned cost. If you have someone else do the tuning, .5 needs sharpening a lot sooner than 1. So that $30-$50 happens every week or two instead of every month or so. And if you try to stretch it out, you might well end u with a dull .5 that's inferior to a moderately sharp 1.

I'm willing to accept your assessment. But I only get to ski 8-10 days a season. After each day during the season, I deburr using a gummy stone and rewax with Toko liquid wax. So, that just means a pro-tune once every autumn, which I consider to be an entirely acceptable expense.

post #19 of 27

I'd like to hear from a metallurgist on this.

 

One thing that is certain is that If you need sharp skis for ice, you need to sharpen more often regardless of bevels. Typically using a guide and series of stones will sharpen the edge bevel sufficiently if you keep up with it (daily). If you do need sharp edges it is worth it to invest in a guide and a few stones. It takes very little skill to use them and as long as you don't try to work your base edges, you are very unlikely to mess up your tune.

post #20 of 27

A few passes with a fine diamond stone after you wipe your skis on a daily basis does a lot to preserve edge sharpness.

I think you would have to look very hard with good instrumentation to prove that a .5 difference in a low angle blade wears out more quickly.

In a high angle blade like a knife it makes a difference.

post #21 of 27
Thread Starter 
Quote:
Originally Posted by dakine View Post
 

A few passes with a fine diamond stone after you wipe your skis on a daily basis does a lot to preserve edge sharpness ...

Yup, that's what I do. (Except for the liquid wax, that's all I do.) Thanks.

post #22 of 27
Quote:
Originally Posted by epic View Post
 

Why would a .5 base need more sharpening? I've never noticed a need for that.

 

Surprised. See below. 

Quote:
Originally Posted by sibhusky View Post

If you buy into a 3° side needing more sharpening than a 2°, then the .5° base would possibly need more than a 1° base, but only half as bad. But most here don't buy the first scenario, so the second scenario is even more iffy.


Not a "scenario," but well established fact; detailed explanations can be found at better knife sharpening sites. A .5 base angle is more acute, eg, "sharper," than a 1.0, in the sense that it's closer to no base angle at all. If you think about the base and edge angle combining to make a new geometric figure, and hold the edge constant at 3, then the resultant is 86.5 for a .5, vs 86 degrees for a 1.

 

Narrower angles are sharper, but also have less mechanical strength at the edge because of less material, so they accumulate invisible damage - molecular chunks and grooves missing - that you can see under a electron microscope; we feel it as "dullness." (Ditto for any sharp thing, in fact. "Dullness" is not smooth wear except at the crude levels our fingers can feel. Just like our "smooth" skin looks like the Grand Canyon up close.) For instance, a razor blade is about 7-8 degrees, and is meant to be used once or twice; a kitchen knife is often three times that. 

 

So yes, a .5 will need sharpening more often because it'll accumulate damage a bit faster. Obviously the timing will depend on how you use the ski. Epic, I seem to recall reading you say that you sharpened your skis nearly every day. So suspect you never noticed because as an instructor, your skis are always well tuned. Can't say as much for the rest of us schlubs...

post #23 of 27
Quote:
Originally Posted by beyond View Post

Surprised. See below. 


Not a "scenario," but well established fact; detailed explanations can be found at better knife sharpening sites. A .5 base angle is more acute, eg, "sharper," than a 1.0, in the sense that it's closer to no base angle at all. If you think about the base and edge angle combining to make a new geometric figure, and hold the edge constant at 3, then the resultant is 86.5 for a .5, vs 86 degrees for a 1.

Narrower angles are sharper, but also have less mechanical strength at the edge because of less material, so they accumulate invisible damage - molecular chunks and grooves missing - that you can see under a electron microscope; we feel it as "dullness." (Ditto for any sharp thing, in fact. "Dullness" is not smooth wear except at the crude levels our fingers can feel. Just like our "smooth" skin looks like the Grand Canyon up close.) For instance, a razor blade is about 7-8 degrees, and is meant to be used once or twice; a kitchen knife is often three times that. 

So yes, a .5 will need sharpening more often because it'll accumulate damage a bit faster. Obviously the timing will depend on how you use the ski. Epic, I seem to recall reading you say that you sharpened your skis nearly every day. So suspect you never noticed because as an instructor, your skis are always well tuned. Can't say as much for the rest of us schlubs...

Just for fun, we can expand on this further by stating if the .5/3 will dull at a faster rate than a 1/3, we also have to accept that since the .5/3 is sharper than a 1/3 to start with, the .5/3 will be duller when compare to other .5/3 but will still feel sharp when compared to 1/3, so the time between sharpening will not shorten as much as you might originally think.

Of course I could be completely wrong but I get to spin things like that at work all the time. biggrin.gif

More importantly, like you pointed out about epic, if you "polish" your edges more frequently, you can maintain a healthy edge longer and reduce the need more more sharpenings.
post #24 of 27
Quote:
Originally Posted by beyond View Post
 

 

Surprised. See below. 


Not a "scenario," but well established fact; detailed explanations can be found at better knife sharpening sites. A .5 base angle is more acute, eg, "sharper," than a 1.0, in the sense that it's closer to no base angle at all. If you think about the base and edge angle combining to make a new geometric figure, and hold the edge constant at 3, then the resultant is 86.5 for a .5, vs 86 degrees for a 1.

 

Narrower angles are sharper, but also have less mechanical strength at the edge because of less material, so they accumulate invisible damage - molecular chunks and grooves missing - that you can see under a electron microscope; we feel it as "dullness." (Ditto for any sharp thing, in fact. "Dullness" is not smooth wear except at the crude levels our fingers can feel. Just like our "smooth" skin looks like the Grand Canyon up close.) For instance, a razor blade is about 7-8 degrees, and is meant to be used once or twice; a kitchen knife is often three times that. 

 

So yes, a .5 will need sharpening more often because it'll accumulate damage a bit faster. Obviously the timing will depend on how you use the ski. Epic, I seem to recall reading you say that you sharpened your skis nearly every day. So suspect you never noticed because as an instructor, your skis are always well tuned. Can't say as much for the rest of us schlubs...

I like this logic, it basically aligned with what was going through my head when the shop pointed it out to me

post #25 of 27

The difference between an included angle of 87 and an included angle of 86.5 is not very noticeable in terms of sharpening requirements and only slightly more noticeable in how sharp it feels on the snow.   The difference in 1 base and 0.5 base is very noticeable in terms of how accurate the ski feels (think on-centre feel/steering slack in a car) and how quickly it responds.

post #26 of 27
Quote:
Originally Posted by Ghost View Post
 

The difference between an included angle of 87 and an included angle of 86.5 is not very noticeable in terms of sharpening requirements and only slightly more noticeable in how sharp it feels on the snow.   The difference in 1 base and 0.5 base is very noticeable in terms of how accurate the ski feels (think on-centre feel/steering slack in a car) and how quickly it responds.

I second that!

Going from 2 to 3° side edge usually mean the skis will continue to behave the same except for sharper edge grip... It only happen ounce, on a rossi pursuit, that I felt that it change how the ski behave and I came back to 2°...

Going from 1°to 0.5° on the base will imply just small changes for some skis ( a little quicker to the edge) but will change a lot how some skis behave or will make them very unconfortable to ski( hated it on sultan legend 85)...

 

Hum... Could it have something to do with torsionnally stiffness of the skis? 

post #27 of 27
The 0.5 give a faster response to edge, down side is it has less forgiveness. If you are balanced and neutral you'll love, if you're not you'll hate it as the skis will bite you.
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