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cracked edges (intentional!)

post #1 of 28
Thread Starter 
On another thread, a writer mentioned the Volkl P9 SLC. This was the first ski I ever bought and its defining characteristic was that the edges were segmented every inch or so along their entire length, opening slightly as the ski was bent. The salesman said it was to increase edge grip. That design feature hasn't lived on, so I wonder if anyone had experience with it or opinions on whether it did, indeed, do anything useful or if there were downsides that caused it to disappear. Thanks!

[ November 19, 2003, 10:45 AM: Message edited by: mike_m ]
post #2 of 28
Segmented edges were primarily a way to reduce high frequency vibrations of the ski on hardpack (ie, sort of like a longitudinal HF filter). The thought was that above a few hundred Hertz, vibrations originating at one point of the ski were transmitted to other parts of the ski through the edges more than through the body of the ski. Segmenting the edges removes this possibility.

I no longer recall the sensations exactly, but I know that when it was icy, I did prefer my skis with segmented edges - they seemed cut into and stay attached to the surface better than other skis I had at the time.

In addition, segmented edges are more flexible than continuous edges, so longitudinal flex could (in principle) be increased. However, lots of other things determine longitudinal flex, so I think this argument is bogus.

I suspect that segmented edges disappeared because other vibration absorping materials became available.

I think that durability was also an issue. Compared to continuous edges, I seem to recall that it was easier for a rock hit to take out a segment or two, but, even if this happened more easily than on continuous edges, the rest of the edge would usually be left relatively undamaged (ie damage was localized).

Tom / PM

[ November 19, 2003, 12:52 PM: Message edited by: PhysicsMan ]
post #3 of 28
I never noticed any difference..when did those things come out anyway?..I bought Olin Mark IV's in 75..they had them..and a few pairs since..I had 3 pairs of P9's(SL) and they did not have them?They were fun to fix..easy..cause it was next to impossible.
post #4 of 28
Quote:
Originally posted by Arnold:
They were fun to fix..easy..cause it was next to impossible.
Ah, the memories- Loved my P9's on the eastern hardpack that passed for snow (especially back then, before the mega grooming machines and all mountain snowmaking)- but I completely delaminated both tips on two different sets within one season, and no I wasn't skiing them in moguls- I agree, implossible to fix, but a great ride while they lasted.

[ November 19, 2003, 02:06 PM: Message edited by: Longboarder ]
post #5 of 28
The writer on the other thread would be me. Please note my portrait >>

Tom/PM, et al.,

With all due respect and in the absence of any formal training as an engineer. I would say that all other things being equal, a cracked edge would, in fact, soften the longitudinal flex of a ski.

At the time, Volkl's design intent was to soften the longitudinal flex. Also, when the ski was flexed, the edge segments opened slightly to increase edge bite or edge hold on hard snow and ice.

Among other, older models, Volkl used the cracked edge on the Targa R and the P9 SLC (Slalom Cracked-Edge). If memory serves me correctly, some Dynamic VR17's employed a cracked edge as well.

Considering that the majority of the frictional losses come from the edges of a ski, rather than the base material; it's not too much of a stretch to figure out that the cracked edge wasn't the fastest tool on the hill.

IG
post #6 of 28
I had a pair of Kastle VCE's (Variable Cracked edge) In the early 70's

They sure caught lint when I wiped the bases with a cloth.

All I knew was they were better than the Yamaha skis with screw in edges I had been using.

Gads! I'm old as dirt!

CalG
post #7 of 28
A friend of mine had a pair of Hexel "Hexceleraters" (?sp) In the mid 1970s. They ahd "cracked" edges. We made quite a few jokes about his edges being broken...
post #8 of 28
Quote:
Originally posted by Inspector Gadget:
...I would say that all other things being equal, a cracked edge would, in fact, soften the longitudinal flex of a ski...
Not to worry. We're saying the same thing. I said, "...so longitudinal flex could (in principle) be increased...". Increasing the flex softens the ski.

Phew! For a sec, I was worried that this was another one of those darn "PM" errors.

Tom / PM
post #9 of 28
I had a pair of K2 SL Race skis in high school (1992 - 1996) that had segmented edges. I was never convinced that they did anything useful. I think I got better edge hold from a nice freshly tuned regular edge.

[img]graemlins/thumbsup.gif[/img]
post #10 of 28
I had a pair of Elan RC SL around 1988 and they had those craked edge. It was one of the nicest ski I had been on at the time. I just loved them.
post #11 of 28
I had cracked steel edges on:
ELAN CR 03 ('76, and lace up soft plastic boots too!)
ELAN RC 05 (c.a. '77)
ELAN Tempest (yep, a powder ski in '78!)
ELAN Comprex S (Ceramic K)
ELAN Comprex Se (Ceramic K)
ELAN Comprex Rs (Kevlar PL)
K2 CSL ('95?)

The primary intent -was- to dampen the ski *EDGE* by freeing individual sections of it to flex with the *BODY*. It really did work well enough on chatter-ice, especially if you remembered to file and stone from tip to tail, so that there would be no sharp jags at the front of each segment.

One of the drawbacks is/was that the base would develop cracks in the sintered Ptex, that looked like little hairs spreading out into the base: imagine a hair- thin Atari logo of cracks at each point. This was especially noticeable on the clear Ptex of the non-Electra bases (Comprex RS and Ultimate M). Eventually, these cracks would cause significant de-lamination of the base from the ski, mostly from water effects, but by that time the bases were so thin the skis were only good for tomato stakes anyway.

Interestingly enough, the unsintered ones did not have this problem.

Heck, if it was good enough for Stenmark, it's good enough for me!
post #12 of 28
Quote:
Originally posted by Inspector Gadget:
The writer on the other thread would be me. Please note my portrait >>

Tom/PM, et al.,

With all due respect and in the absence of any formal training as an engineer. I would say that all other things being equal, a cracked edge would, in fact, soften the longitudinal flex of a ski.

At the time, Volkl's design intent was to soften the longitudinal flex. Also, when the ski was flexed, the edge segments opened slightly to increase edge bite or edge hold on hard snow and ice.

Among other, older models, Volkl used the cracked edge on the Targa R and the P9 SLC (Slalom Cracked-Edge). If memory serves me correctly, some Dynamic VR17's employed a cracked edge as well.

Considering that the majority of the frictional losses come from the edges of a ski, rather than the base material; it's not too much of a stretch to figure out that the cracked edge wasn't the fastest tool on the hill.

IG
You missed out on a great ski - the Elan RC Comp Titanium. I have a pair of 200cm which have a cracked edge (old traditional skis). A cracked edge is great on ice, boilerplate, and had great rebound, a very stiff tail that rocketed you out of the turn.

I think Volkl had one ski model that had cracked edges (left and right skis) on the inside (inside edge), and they had a continuous edge on the outside. A friend of mine had a pair, and he would put the left ski on his right boot, and vice-versa. You could use one ski for Slalom and (see above last sentence) Giant Slalom.
post #13 of 28
I believe that it was 64, my first skis were (Elan) with a cracked edge .... each piece was screwed on ...

They were wood skis and the sales pitch was that they would "snake across the snow" and hold on better than those "newer type skis" ....... I guess he meant all the junk by Head and Hart .... good old wood was the way to go.
post #14 of 28
Quote:
Originally posted by powdog:
You missed out on a great ski - the Elan RC Comp Titanium. I have a pair of 200cm which have a cracked edge (old traditional skis). A cracked edge is great on ice, boilerplate, and had great rebound, a very stiff tail that rocketed you out of the turn. .
Nope, still have one pair with the grey/pink topsheet in 203cm (w. Atomic 614 and RaceCharger plate it's verrrry interesting).

I only retired the Kevlar PLs after the wood around the binding screws literally dry-rotted.

Quote:

I think Volkl had one ski model that had cracked edges (left and right skis) on the inside (inside edge), and they had a continuous edge on the outside. A friend of mine had a pair, and he would put the left ski on his right boot, and vice-versa. You could use one ski for Slalom and (see above last sentence) Giant Slalom.
Dynastar had something like that (something or other Fusion model); still gives me the heebie jeebies, more even than having one Comp Ti and one Ceramic K.
post #15 of 28
How could I forget, powdog and comprex are referring to the Volkl Gemini. Definitely an upper-crust ski that had a solid edge on one side and a cracked edge on the other; the sidecut was different from side-to-side as well. So, depending on conditions, your general mood and disposition; you could ski them as a slalom ski or a giant slalom ski by simply changing skis from foot-to-foot.

I have a pair in the garage, too bad they're not worth a plug-nickel.

IG
post #16 of 28
Quote:
I have a pair in the garage, too bad they're not worth a plug-nickel.

IG
Awwww. Bindings still OK? Bring them out and I'll bring the Fels for a day of complete silliness?
post #17 of 28
The Dynastars came out in 88/9..I had them.They were Fusions..and came in 3 levels..HC,HX and HZ..they did not have cracked edges..BUT had..a harder and softer edge on each side of the ski.Not the edges per se.just the sides of the skiis.I don't know if all/any was in the base structure,sidewall,or composition of the skis.Both skis were oppossites.Meaning that you were ALWAYS skiing on similar inside edges..and oppossite edges on the outsides.

Ya..ya figgerred this out..weighting a downhill ski..on a harder..or softer inside edge(depending on how you were wearing them)..and just the OPPOSSITE on your uphill ski..

Made for some "interesting" dancing..during transition..or equal weighting.These things were soft,LIGHT,quick/reactive..next to impossible to ski that traditional of the time..independant leg action.They really required some weighting on both skis all the time.If ya didn't..and found yourself at hi-speed without enough weighting on your uphill ski..with 2 oppossite edges..a hard,and a soft..flapping around..It woke you up.

Some magazines,testers rated these things(the HZ's) as a "super expert ski) with a great kick in the tail..I don't know about that..not that I am qualified like that.They were certainlly no ski for beginners,intermediates.I did lend them to several ski buddies at the time..they all got a bit spooked..I had pretty good bevels put to them..that took some of the grab out of them..

I always found them lively when skiing on the softer inside edges..and BORING when on the hard edges.

Blizzard had at one time..it could have been earlier/later pretty much the same ski..can't remember the model..

Great memories!
post #18 of 28
Quote:
Originally posted by Inspector Gadget:
... If memory serves me correctly, some Dynamic VR17's employed a cracked edge as well.
Looks like the Ginko Biloba is starting to pay off Inspector. You are correct.
I have a pair of 204cm VR17's in my basement, from about ~1980? Never even skied them that much because (surprise) I blew out a couple of edge segments.

I also skied on a 207 P10 SLC for about 3 yrs. and never had a problem with the cracked edges on them. Great bump ski. Sold them to a friend and he jumped into Corbett's Coulior on them about 5 years ago. Brought fu#@$ng tears to my eyes. [img]graemlins/evilgrin.gif[/img]
post #19 of 28
Quote:
Originally posted by Carvemeister:
Looks like the Ginko Biloba is starting to pay off Inspector. You are correct.
Like I always say "Better living through chemistry".

Quote:
Originally posted by comprex:
Awwww. Bindings still OK? Bring them out and I'll bring the Fels for a day of complete silliness?
comprex,

If I were going to bring out some old skis for a day of silliness, I'd bring one of the following:

</font>
  • 210cm Volkl Dream Skis with Ess Racing bindings.
    Volkl built the Bavarian Dream skis in two different models, they are painted with flowers and resemble the shutters you might find on a chalet in the Alps. I used them for a couple days at the Salt Lake Olympics on the downhill and super-g courses. These never fail to elicit some quizzical looks and comments.</font>
  • 218cm Kastle DH with Marker MRR bindings
    Speed tested for the Lake Placid Olympic downhill. Kastle put new top-skins on and gave them to me as a gift. The skied like a long GS ski, powder and all. I raced on them in a Camel Speed Skiing series race at Snow King, Jackson Hole. Truly one of the fastest straight-line skis I've ever been on.</font>
  • 210cm Rossignol Stratos with Cable bindings and long-thongs.
    Bought 'em at the REI ski swap. I loved my Stratos, I couldn't just leave them there. Could I?</font>
IG

[ November 28, 2003, 07:56 PM: Message edited by: Inspector Gadget ]
post #20 of 28
I think Dynamic had SOME issues with the cracked edge thing..I had an ancient pair of VR17's..pale green..no cracked edge.Then I had the later..black VR17's..hey look ma..cracked edges..THEN I had the later VR 27..no cracked edges??

I/G..I had a pair of Kastle "National Teams"(214)..I bought them used..cheap..just for a hoot.It mustta been the/that base structure..or a multiple type structure..waxing?..Idno..I never fiddled with them.These things were SO slooooww...at first it was stupid..BUT then hey guess what..they were EXTREMELY resistant..to just about ANY attempt to slow them down.They were like a freight train..at a certain speed..I don't know why..base structure/wax?..they just took off at warp speed..I had a few scares on them..I am a fairly good strong skier..6' 210lbs..but these things were simply out of my league..I had way too much trouble controlling them..mainly speed check.I'ld say slow down!! and they'd call me a wuss..and worse.I gave them away.
post #21 of 28
I had a pair of Völkl SP-9's with cracked edges. I think they were 195's. They were awesome on ice. Any of the P-9, P-10 series, especially racing stock, had superb edge hold and could turn on a dime on ice. I think they stopped using cracked edges due to advances in construction. I imagine it would still be viable in some skis that were the old traditional torsion box construction. Those torsion box sandwich-type skis were wonderful anyway. Some companies also had low-profile narrow edges on their racing stock. I know of at least one eastern ski shop that was center cutting the edges for better hold on ice in the past.
P.S. Actually they are still in the garage. [img]tongue.gif[/img]

[ December 02, 2003, 12:20 PM: Message edited by: Jørn ]
post #22 of 28
You are referring to the ICE edge grooving machines, that would groove the base side of the edge parallel to the side cut of the ski? Or are you referring to a (to me hypothetical) machine that might cut orthogonally to a tangent of the side cut?

The one shop near me as had one apparently sent it back in '99 or thereabouts.

Do we know of any shop that still has these?

Hmmm. PM, you still out there? Would this be theoretically different from Hexcel's Blue ICE edges (4 per ski?)

[ December 02, 2003, 01:37 PM: Message edited by: comprex ]
post #23 of 28
Kastle CPM 70's, circa 1968, had cracked edges. These were a composite metal/fiberglass ski. I still have mine somewere in the barn.
post #24 of 28
Err, Arcadie ... this is embarrassing ... I have *two* pairs of Kastle CPM Ti's in my shed that have been keeping each other company for the past (ahem ... clear my throat ...) 35 years. One pair is a white and orangish-red "CPM 4000 Ti" version and the other is a black and orangish-red "CPM Ti". All I remember about them was that the 4000 skied terribly - twitchy as all getout, whereas the plain CPM Ti was wonderful (or maybe it was visa versa).

Arcadie - if I send you my two pair, you will be well on your way to being able to put together some nice matched ski furniture. Are you sure I can't interest you in them? [img]graemlins/evilgrin.gif[/img]

Tom / PM

PS - Comprex - Yup, I'm still around, but got kinda busy with the holidays, work, preparing for the ski season, etc., so I've just been trying to do short posts instead of my usual tomes. To answer your question, I have to confess that I never actually looked into the science behind the various types of edges for ice. My initial guess is that on perfectly smooth ice, a single acute-angled edge would concentrate the pressure the most and hence penetrate the most deeply and have the best grip, whereas if the terrain is slightly irregular ("slightly" might only need to be a mm or so), two edges (if configured properly) might be able to maintain contact best, but at this point, I really only guessing. If I find anything out, I'll let you know.

[ December 02, 2003, 09:45 PM: Message edited by: PhysicsMan ]
post #25 of 28
No mention of the spankingest ski ever?! K2s VO slalom had cracked edges.
post #26 of 28
Quote:
Originally posted by comprex:
You are referring to the ICE edge grooving machines, that would groove the base side of the edge parallel to the side cut of the ski? Or are you referring to a (to me hypothetical) machine that might cut orthogonally to a tangent of the side cut?

The one shop near me as had one apparently sent it back in '99 or thereabouts.

Do we know of any shop that still has these?
I was referring to the ICE machines. I do not know if anyone still uses these machines.

I believe Völkl used low-profile narrow edges on their racing stock P-9's. Kneissl made some Racing Team A's many years ago with low-profile narrow edges. I think Atomic has produced some racing stock with narrow edges. The narrow edge maximizes the amount of P-tex that is in contact with the snow surface.

I have always liked racing stock skis. I sometimes like to ski on ice.
post #27 of 28
Is anyone familiar with the dual-base dual-structure Kastles as shown
here

(Ebay item 3644569295 Kastle RX Extreme)
post #28 of 28
Comprex..don't quote me on this..I do have a pair of..no..I have 2 pairs of skis with this base..and last year got rid of a pair of RX's with that base.

I think the Kastle "fast base" came about around the time when the technolgy and machinery became available to stucture bases in other than the traditonal way..rill..

Perhaps they as manufacturers had the jump..I don't know.

Seems to me it had not just the straight structuring but an angle to it as well..this obviouslly an attempt at holding wax better. The Kastles I have that are straight(as well as the ones I got rid of) are the "Fast Bases"..

I also have a pair of Kastle Aeropseeds("shaped) I think these say "fast base" also but I don't think it has anything to do with the structure anymore..more the base itself.

Sorry but the skis have had tradional structures put on them..with no difference..so even if I examined them with a magnifier they'd look the same
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