Retuning edges on DH skis.

[Speeder]

I recently attended a tuning workshop for downhill ie 218cm 50m radius skis. The tech who has WC experience said to detune the edges on the first and last 1/4 of the running surface and leave the center half sharp. For example if the running surface was 100cm the front 25 and the back 25 would be detuned. He said it would prevent the tails from catching at the end of the turn. Is this the way to go or just more BS? My DH skis are as sharp as I can make them front to back. Any thoughts?

 

[S.H.]

Depends on:

• surface
• set
• racer ability
• racer preference
• a bunch of other things

This could be the way to go or could be a terrible idea, depending on a host of factors. I wouldn't do this if you only have one pair of DH skis though... detuning 50% of the edge seems like way too much. Would advise less (10-15 cm tip/tail), probably.

 

[Primoz]

For DH this is standard PRACTICE. Not 1/4 as that would be about 50cm front and 50cm back, but some 10 to 15cm. From there on, it depends on snow, and it can be that whole outside side of ski is done with gumi stone to get sharpness off. But as I wrote, that depends on conditions.
One thing is, you don't want skis to hook, that's why most of guys run DH skis with 1.2 to 1.8deg on base. And second, sharp edges are slow, so you make them only as sharp as necessary and not as sharp as possible like it's normally with SL and GS

 

[Muleski]

https://www.pugski.com/threads/svst-final-cut-1-5-degree-base-bevel-guide-unused.12666/

You obviously need to buy this.....unused 1.5 degree bas bevel. SVST Final Cut.

 

[Speeder]

For DH this is standard PRACTICE. Not 1/4 as that would be about 50cm front and 50cm back, but some 10 to 15cm. From there on, it depends on snow, and it can be that whole outside side of ski is done with gumi stone to get sharpness off. But as I wrote, that depends on conditions.
One thing is, you don't want skis to hook, that's why most of guys run DH skis with 1.2 to 1.8deg on base. And second, sharp edges are slow, so you make them only as sharp as necessary and not as sharp as possible like it's normally with SL and GS

Thank you for the reply. I only race one DH a season and the snow is usually soft and there is no ice. Would you recommend detuning the whole length in this case?

 

[James]

Are we talking just a hard gummi stone for detuning?

And second, sharp edges are slow, so you make them only as sharp as necessary and not as sharp as possible like it's normally with SL and GS

I think it was during the Sochi downhill training that Bode was on tv talking about how you wanted the edges as dull as possible but sharp enough to get the job done.
Of course probably the last time he tuned his own ski was in like 1997.

 

[Jason Kurth]

interesting....

 

[Primoz]

Thank you for the reply. I only race one DH a season and the snow is usually soft and there is no ice. Would you recommend detuning the whole length in this case?

Personally, yes. But.... Yeah there's always but It depends on racer. Some racers need super sharp edges, others get away with super dull. I had racers like that and their skis were like day and night. I was just in ski room of really good friend of mine in Garmisch, and Garmisch was pretty soft, at least compared to Kitzbuehel previous week, and we were discussing these stuff. One of his racers wants really sharp skis, and when I checked that ski I was like "what??!! for this snow???". Other got whole outside edge detuned for that race (which on the end didn't happen). But what's interesting, guy with sharper skis is actually faster on glide sections then the other one. And no, it doesn't mean sharper skis are faster, but just that your ability to glide and keep skis perfectly flat matters more then ski preparation
One more thing... with detuning whole length I meant outside edge of ski. Inside should still be sharp and not detuned except first and last 10-15cm of edge. But you have different ways of sharp of inside edge. It can be super sharp (like when done with machine), or it can be a bit less sharp. Sure you can't do it 3 or 7% less or more, but you can still do it more or less sharp depending on conditions.

Are we talking just a hard gummi stone for detuning?

Yes just that. I'm sorry as someone here once wrote that's not really detuning and I was excused only that single time to use detuning word in such case, but I'm sorry I forgot how should I really call that with right expression

Of course probably the last time he tuned his own ski was in like 1997.

It's true he probably doesn't even remember how it is to prepare skis, but thing is, serviceman and racer discuss these things and check during trainings what's best option for race. Servicemen know whole bunch of stuff, and when they go for course inspection (normally hours before racers go), they see how is track and they know what to do, but racers are the ones that ski, and only they can tell what exactly it was happening with ski during run. So if they had too little or too much grip, they tell that and sharpness is changed for next run.

 

[Speeder]

Personally, yes. But.... Yeah there's always but It depends on racer. Some racers need super sharp edges, others get away with super dull. I had racers like that and their skis were like day and night. I was just in ski room of really good friend of mine in Garmisch, and Garmisch was pretty soft, at least compared to Kitzbuehel previous week, and we were discussing these stuff. One of his racers wants really sharp skis, and when I checked that ski I was like "what??!! for this snow???". Other got whole outside edge detuned for that race (which on the end didn't happen). But what's interesting, guy with sharper skis is actually faster on glide sections then the other one. And no, it doesn't mean sharper skis are faster, but just that your ability to glide and keep skis perfectly flat matters more then ski preparation
One more thing... with detuning whole length I meant outside edge of ski. Inside should still be sharp and not detuned except first and last 10-15cm of edge. But you have different ways of sharp of inside edge. It can be super sharp (like when done with machine), or it can be a bit less sharp. Sure you can't do it 3 or 7% less or more, but you can still do it more or less sharp depending on conditions.

Yes just that. I'm sorry as someone here once wrote that's not really detuning and I was excused only that single time to use detuning word in such case, but I'm sorry I forgot how should I really call that with right expression

It's true he probably doesn't even remember how it is to prepare skis, but thing is, serviceman and racer discuss these things and check during trainings what's best option for race. Servicemen know whole bunch of stuff, and when they go for course inspection (normally hours before racers go), they see how is track and they know what to do, but racers are the ones that ski, and only they can tell what exactly it was happening with ski during run. So if they had too little or too much grip, they tell that and sharpness is changed for next run.

Thank you for your reply. I will try detuning gradually for training in the next race.

 

[James]

Yes just that. I'm sorry as someone here once wrote that's not really detuning and I was excused only that single time to use detuning word in such case, but I'm sorry I forgot how should I really call that with right expression

Hah, yeah here "detuning" usually means sawing away with a diamond stone across the point of the edge to dull it. Sometimes even a file.

I don't think we have good words for what you describe. " Relieving the sharpness" perhaps.

I found this video where Aksel LS and Kjeitil J discuss edges at 5:20

 

[James]

Heinz- 0.1 to 0.2 base edge.
Gs- 86 deg, Slalom 85, Dh/sg 87.
Didn't go into base for speed.

How does one get such small base distinctions 0.1 or 0.2?

 

[Primoz]

How does one get such small base distinctions 0.1 or 0.2?

Machines.. . nowadays base angles o race skis are in majority done in factory when base is grinded and then (base) edges are done too. Serviceman tells what he wants and he gets skis back with desired angles. Side angle and sidewall are still serviceman job.

 

[D Lamour]

How long does a ski 5 degree edge last?

 

[James]

Skis are sharpened after 1 run I believe.