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Serrated Edges for Injected Courses

post #1 of 13
Thread Starter 

I read in a back issue (Dec 2009) of Ski Racing Magazine that the Ladies SL course at Beaver Creek was injected and too icey for the women. Linsdey V said that what she needed was serrated edges for that kind of ice. I've never heard of serrated ski edges. I don't think she meant cracked edges or she would have said so. Has anyone ever heard of serrated ski edges?

post #2 of 13

They use a machine like this to do it - http://www.verdonkracing.com/index.htm. They are micro serrated though, not like a knife, but if you ran your hand down the edge, it would draw blood! So you can't fall on your ski...

post #3 of 13

Sounds almost like an intentional hanging burr

post #4 of 13
Quote:
Originally Posted by Speeder View Post

 Has anyone ever heard of serrated ski edges?

 

Lib-Tech have been putting serrated edges on their snowboards for years now: search on this forum and others for "Magnetraction".   

 

Look on their website under NAS (For Narrow Donkey Snowboards) for their ski models with that feature.

 

This is different than the micro-serration neutrino1 talks about above.

post #5 of 13
post #6 of 13

Article referred to by OP (I think)

 

 

Quote:
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ASPEN –The FIS made a decision last spring to inject all women’s technical courses this season. It most likely is a mistake.

Unfortunately for the women’s slalom here, an amalgamation of a high pressure system, cold temperatures and injection combined to create an exceptionally slick surface. The first run result was mayhem as 24 racers failed to make it to the finish, one third of the field. As athlete after athlete slid, somersaulted or just skied off course, fans resorted to cheering racers just for finishing. It wasn’t a pretty sight for either fans or the television audience. 

First let’s set one thing straight. This was NOT the fault of the Aspen organizing committee. They simply carried out the preparation as the FIS directed, in this case the women’s technical director, Markus Mayr. What the FIS and Mayr found out was the outcome of injection at 8,000 feet with low humidity is far from an exact science.

“It was too icy,” emphatically said Atle Skaardal, chief race director of the women’s circuit of the first course. 

In defense of the decision, injection offers more flexibility and in most cases a fairer surface. It is a must for men’s technical racing as their strength ruts a course early on making it impossible for later starters to have a chance at a second run. The same is not as true for women which is why coaches and racers are questioning the injection dictate.

On Aspen’s Ruthies Run, which is steep with break overs, injecting makes an already tough course all the more difficult.

“It is not the answer,” said Patrick Riml, head coach of the Canadian women’s team and former head coach of the U.S. woman’s squad. “Look,” he added, “Today we could have raced on the pure manmade surface Aspen put down without any difficulty, but that is today.”

Riml pointed out that one impediment with using non-injected manmade snow comes with natural snow falling on it. “That can be messy and make the surface dangerous,” he said. “If the surface is injected, it is much easier to move the new snow off and have a good surface.”

Injection has spawned other concerns, primarily about injuries and bodily wear and tear. During the giant slalom, Denise Karbon, who won the title last season, came up limping with a torn meniscus after a ninth-place effort on a rock-hard Ruthies Run. There was no fall, no strange turn but the damage was done. One can’t blame the injected surface outright but it raises questions.

“You needed a serrated edge,” commented Thomas Vonn, husband of superstar Lindsey, who skied out, but not because of the ice.  “I think they are hurting the sport by preparing courses like this. It is not about who is skiing fast, it is about who is screwing up the least. That is pond ice up there. This is alpine skiing, not skating.”

Vonn, too, worries about injury or nagging health difficulties. “You have to train on ice to race on ice. It just wears you down.”

Another factor is the skis and plate set ups the athletes are using in slalom. The Austrians were venting over the combination of sharp turning skis and ice, saying the combination can be terribly dangerous. The Austrian team lost Alexandra Daum most likely for the season with a torn ACL after a sharp fall where ice was a contributing factor.

Skaardal knows the concern and worries. You can see it in his face when he discusses the race conditions. He is not ready to talk about what the next step will be, but you come away with the impression things will change. They have too. Woman’s ski racing is struggling for television time and attention. It doesn’t help to have them looking like duffers on too slick a course. And it doesn’t help when superstars look less than super.

There may be places for injection, but it shouldn’t be mandatory. Women’s World Cup racing will be better served with a flexible policy not water in the snow. Use injection as a tool where needed only.

- G.B. Jr
post #7 of 13

Article by Vonn relative to another race:

 

 

Quote:

Vonn: Serrated edges key in Sunday's icy slalom

By Lindsey Vonn
Special to The Denver Post
Updated: 01/12/2009 01:13:13 PM MST

 
 

MARIBOR, SLOVENIA — World Cup overall champion Lindsey Vonn, a product of Ski Club Vail, reports regularly from the tour in collaboration with Denver Post ski writer John Meyer.

My experience in Sunday's slalom really bears out the importance of proper ski preparation and having edges sharp enough for the conditions.

The courses here were extremely icy, like an ice-skating rink. In the first run, my edges didn't grip well and I finished 18th. I slipped out of the course on like the fifth gate and skied conservatively from there, just trying to get to the finish. I slipped again near the bottom and almost went out of the race.

Even with the extremely sharp edges we normally use, that just wasn't adequate. You needed a serrated edge. It's like a steak knife, as opposed to a butter knife.

My ski tech serrated my edges for the second run, I gave it everything I had while still being smart with my tactics, and it was light years better. I put down the fastest second run and ended up in fourth place.

Considering what happened in the first run, it was a good day. To move up from 18th to fourth is pretty sweet.

You have no idea how careful you have to be with edges as sharp as I had for the second run. If you run your finger down a serrated edge, you would cut your finger seriously. It's very, very dangerous. The edge I had for the first run was very sharp as well, but it was smooth. You could run your finger down it without cutting it.

The rest of this month will be really important for me in the overall title chase. Because of weather cancellations we've had only one downhill so far this season, the one I won in Lake Louise. Now five of the next eight races are speed races (downhill or super-G), plus a combined race (slalom and downhill). That stretch, which starts this coming weekend in Altenmarkt, will be followed by the world championships in Val d'Isere.

The next three weeks are going to be really tough, with a lot of races crammed into a short period of time — eight in 15 days and four in Cortina d'Ampezzo (a super-G, two downhills and a giant slalom), Jan. 22-25.

It's going to be difficult, but I feel pretty good. I feel like my energy is still pretty high. I'm just really looking forward to getting back on the long boards this weekend.



Read more: Vonn: Serrated edges key in Sunday's icy slalom - The Denver Post http://www.denverpost.com/preps/ci_11435013#ixzz149NSvvX0
post #8 of 13

Just curious, but are they talking about serrated edge, or something closer to a scalloped edge?  It seems that serration would cause a serious friction, while scalloping might increase the bite without slowing down the skis.  Isn't there an indy ski on the market with scalloped edges?

It's not a race ski I'm talking about - it's one of the fatties.

post #9 of 13


 

Quote:
Originally Posted by incognito View Post

Just curious, but are they talking about serrated edge, or something closer to a scalloped edge?  It seems that serration would cause a serious friction,

 

 

while scalloping might increase the bite without slowing down the skis.  Isn't there an indy ski on the market with scalloped edges?

It's not a race ski I'm talking about - it's one of the fatties.

 

They're talking about serration. 

 

You are right, serration of one surface /can/ increase friction between two surfaces.   Two conditions generally exist when that happens:   the second surface is also rough and the motion between the two is slow enough to create "grab".

 

In this case, I believe the idea is to have both those criteria fail.      The second surface (the ice groove formed by a carving ski) is already polished smooth by the previous sections of edge passing through, and the serrations pass through too fast for the meltwater or the snowiceslush to rebound up into the serrations.   

 

 

I think the Lib-Tech I mention above is probably the 'scalloped' fatty you're thinking of.
 

post #10 of 13
Thread Starter 

Thanks for your responses my apologies to sibhusky for not finding the previous discussion it was very informative and the SR article you posted was the correct one. The Verdonk Machine looks like it makes the edges smoother than hand stoning so I don't think that's what she meant (but I stand to be corrected). LV says in the other article posted by sibhusky "like a steak knife"; she may be being overly euphemistic here but it suggests to me a lot of small “V” notches or small shallow dished scallops cut into the side edge, I have steak knives in both styles. She also says her tech did it to the edge between runs so there must be a tool that makes the cuts fairly quickly. Her comments also suggest to me that it is an unusual step so it might be a one time add on to an already race prepared ski and the serrations need to be removed to retune the edge. There seems to be no mention of using this technology for the men’s skis presumably because the men are heavy and strong enough to cut into the injected surface.

I agree that under normal firm race conditions this kind of treatment is bound to slow the ski dramatically as compared to a smooth sharp edge but there’s a good analogy to be made with intermediate tires vs. slicks on an F1 car in the wet.

The answer is out there......

post #11 of 13
Quote:
Originally Posted by comprex View Post


 

 

They're talking about serration. 

 

You are right, serration of one surface /can/ increase friction between two surfaces.   Two conditions generally exist when that happens:   the second surface is also rough and the motion between the two is slow enough to create "grab".

 

In this case, I believe the idea is to have both those criteria fail.      The second surface (the ice groove formed by a carving ski) is already polished smooth by the previous sections of edge passing through, and the serrations pass through too fast for the meltwater or the snowiceslush to rebound up into the serrations.   

 

 

I think the Lib-Tech I mention above is probably the 'scalloped' fatty you're thinking of.
 

You're right - this is what I was thinking: http://www.powdermag.com/news/lib-tech/

A friend tried them and was very impressed with the edge hold, to the point of thinking that they were too grabby/hooky.  However, it was towards the end of the season, and the conditions weren't exactly boilerplate.

 

 

 

 

 

post #12 of 13

FWIW, the wavelength on Lib-Tech's  "scallops"  is about 10 inches.

post #13 of 13

Hey Speeder! It's a ceramic disc finish you are wondering about and can be achieved very easily with a Discman, a handy tool Wintersteiger have been making for a while now (http://www.wintersteiger.de/en/Sports/Accessories-und-Spare-Parts/Workshop-Accessories/Edge-Care). Ideal for track-side tuning for icy conditions, about the size of an angle grinder. As opposed to regular tuning, a disc finish sharpens across the edge and from both ways (opposite sides of the disc) leaving no burr. The trademark is the 'scallop' half moon effect mentioned. The friction created by this finish gives superior grip on the bullet-proof, not to mention a near 100% true edge. Forget the 'Lib-tech' style wavey edges theory. That's a type of edge construction, not a tuning method ;)

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