Fin Adjust for funky off-side behavior?

[Than_Bogan]

I've tried some technique adjustments first, and they only seem to reduce the problem, not eliminate it, so I'm looking to do some fin adjustments next.  But I've never really had a problem exactly like this, so I'm not quite sure where to go.  All suggestions appreciated.

When I come to the finish of my off-side turn, especially at -35 and -38 (55kph), the ski seems to breifly lose edge and -- for lack of a better word -- become squirelly.  Sometimes it "squirrels" so much that it actually goes onto the opposite edge before I can regain control and begin my pull.  Needless to say, this leaves me late into the next ball!  As I progress through the lines, this issue becomes progressively worse.

I'm on a 9900SL, and I like an awful lot of what it does.  But I need to fix this particular issue.  I'm using the 7 degree setting that I have used on every ski I've owned for years.

Also of note: I'm currently both deeper and longer than factory.  I tried out the factory settings (with my standard 7 degree) last fall and I was shocked at how bad it felt.  My notes say "nearly unskiable."  Of course, it's always possible I measured wrong.

Other things that probably don't matter, but just in case:

The last ski I had REALLY dialed in was a 9600, but it had some structural issues and eventually became very soft.  I've also had some injuries since then, but seem close to 100% now.

My personal best is 4.5 @ -38 (practice 1 @ -39), but it's been a few years since I went deep at -38.  I *think* I'm physically ready to do that now, but I need to tune up both my technique and (I think!) my ski.

All advice appreciated!!  Also, I'd be interested in any links to useful info.

[Horton]

Normally I would tell you to add a bit of length.  Since you are already long and deep I wonder if you might try a smidge shallower.

[Boody]

I have the same ski, i would definately run 9 degrees, not 7. You need this at -35 and -38. Plus it's what Goode recommends. I moved my fin from 8 to 9 and I like it better.

[Roger]

Sounds like it's over-pressuring in the turn and releasing too hard at the end of the turn. If the bindings are in the correct position, then I would shorten the fin (take some off-side tip out). If the fin does this at near stock numbers, then I would move the bindings back a bit. I also agree with 9 degress of wing angle for the Goodes.

[Than_Bogan]

Thanks guys!  Great input to consider in my search.

I don't think I can really consider 9 degrees, unless you are claiming the 9900SL is somehow different from previous Goodes.  I've tried 8 on several previous Goodes and didn't like it at all.  Very "sticky" feel in the turns.  I don't know anybody else who runs as little wing on a Goode as I do -- something weird about my skiing style I guess.  But I've been doing it for many years -- I actually used to run 6 degrees way back, but found I preferred 7 on a Goode.  I suppose it wouldn't hurt to try 8 again, but I'd be really surprised if that feels better.

Been surprised before...

[Than_Bogan]

Hm, I never really considered my boot placement -- it came mounted up from the factory.  But considering how bad the factory fin settings felt, I suppose it's possible the binding positions IS off.  Argh -- I don't need more variables!  Guess I better remeasure that before I go much further.

That said, I wouldn't *think* that moving them back would be workable, because I'm already have a little trouble with rocking back on my on-side, which I'd have to think would be worsened by moving the boots back?

Of course, sometimes the intuitive guess at what an adjustment will do is completely wrong!

[Than_Bogan]

Btw, here's an interesting link:

http://www.jagersport.com/FMTECH_0204.pdf

From reading this, it seems like my first action would be to move the fin back. (?)

[Roger]

New ski basics (for me at least):

Set fin to factory stock numbers.

Ski bindings in stock position.

Ski bindings in one hole forward position.

Ski bindings in one hole back postition.

Set bindings to best of above tests (or repeat test with best from above plus one more hole, etc).

Tune remainder of issues with fin adjustments.

Getting the bindings set first is critical to everything else working correctly (IMO).

[Horton]

Roger speaks logically

[Roger]

I do not agree with most of what he says in that document about DFT. Moving the fin back generally gives you more tip (brings the tip down) on the On-Side turn, not the off side. To add tip (bring the tip down) on the Off-Side, you would lengthen the blade. If you need to reduce tip on your offside for your issue, you would shorten the length of the blade, not mess with DFT. This is how Schnitz (who invented the thing) and the Goode and D3 documents I recieved with my skis describe it. It's also how its always worked for me, I move the fin back if I need more tip on my On-Side; I lengthen the blade if I need more tip on my Off-Side.

Schnitzer's instructions in the original adjustable fin said to increase blade length until you break at the waist on the off-side turn and then reduce the length by .005.

 

[Horton]

Length = drag

Drag can offer stability off the ball

[Drago]

Is the rope tight when the wiggle happens?

[Chef23]

The wing is an easy change to try. That should offer some additional stability. I would give that a crack after re-checking your fin settings to make sure they are what you think they are.

[Boody]

You may not like the "sticky feel" at your lower passes but at 35 and 38 I doubt it will feel that way. Plus the wing adds stability. It is no accident that most shortline skiers run their wing at 9. If it doesn't work, it takes 1 minute to put it back, jeesh.

[aguylikeshark]

every fin adjust does the same thing both sides that how you experience the effect is different.

so fin back basically adds to the tail of the ski, raising it (the tail) up and putting the tip lower - but also making the turns rounder, finishing tip lower. reduces slip on the ski 

moving boots ahead is very similar. with boots you need to find that center point on the ski. water conditions, ski flex and the type of boot you are in will change how you stand on the ski. (i don't like plates with these 0.25" jumps in position.)

in cancun right now skiing warm salty water. this spongy stuff is much harder to read what is going on with the ski.

adding fin length just increases the fin surface area - this will be a boost to offside but hurt your onside unless you reduce depth by ~1/2 at the same time.

9 degree wing is pretty steep, tried it here didn't like it. the new goode models are running 7 degrees ?? the pros i've talked to run 7 or 8.

 

[jimbrake]

Isn't there a "formula" for if you move bindings back or forward that you should move your fin in the same direction some percentage? I've been trying an A1 after being on a D3 Nomad for 3 seasons. The A1 with stock binding position just had too much ski edge in the water. Nice angle, but just tons of load on the body. Moved bindings back a hole and it really freed up the ski. Still generated good angle with a lot less load, but...it made the onside turn a little more unpredictable. Too quick of a finish. Fin back seems like the logical move. Was just wondering if there is a recommended amount.

[Jim Neely]

Move fin one tenth as much as boots.

[Than_Bogan]

Thanks to all!  I'm learning and I found a lot of information here and elsewhere.  I've made *some* fin adjustments before, so I sorta know the drill, but I'm *far* from an expert on it.

In retrospect, I didn't give you guys all the information.  As I was reading through various material, I realized that some of my other symptoms, notably including those on the on-side, were relevant in determining exactly what adjustment could help my overall results.  Here's the two pieces of critical information that I left out (although I didn't realize they were critical!):

1) My DFT was 0.72", which is about 1/100 forward of factory.  (I don't have a slot caliper yet, so this measurement is barely repeatable to a 1/100" -- reporting 1/1000ths would be completely meaningless.)

2) I've been riding a bit toward the tail on the on-side -- just a few days a good skier in NH that I had a chance to ski with advised me that I should make an effort to get more ski in the water on the on-side.  I was able to "fix" THAT just by doing it consciously, so it didn't occur to me that it was relevant to figuring out my ski's adjustment.

As I read material here, in Goode's docs, and in Jager's docs, it began to make sense that the symptoms on both sides were actually tied together, and the only adjustment that sounded like it would take BOTH toward a better direction was reducing DFT.

Btw, I rechecked by boots and they are exactly at factory.

Horton, why do you say Jager's info is wrong?  It seemed to make sense to me, except that I was a little put off by the tone of certainty -- I think anybody who has actually done this knows it simply isn't an exact science.  But you have to start with a general theory and THEN deal with exceptions; it is of no value to assume that *everything* is an exception.  Anyhow, his discussion about symmetry as it relates to DFT seemed to ring true for me.  I've been coming into 1/3/5 wide, but having trouble getting out of there.  I've been coming into 2/4/6 narrow (even on the rare occasion I get out of 1/3/5 well).  For this scenario he recommends decreasing DFT, which appears (after only one easy set) to have significantly improved my feeling of symmetry.

I'm not saying I'm done, but a few passes this morning felt MUCH better -- until I realized that my velcro had started to peel off and I needed to stop skiing before going flying!!

 

@ Drago: Yes, was typically tight at that point.  Slack, if any, was usually on the other (on) side.

[Drago]

My experience/theory:

1)I think most go with too much fin length. Yes, it helps you ski come around on your off side, But: it is flat with the tip down--usually the skier has to/is able to keep too much weight on his back foot. The rope gets tight too early and you have weight on your back foot= do the wiggle and you have to pull back like heck. With less fin length, you can stand up over the ski more neutral and the ski will finish with more speed and more edge angle. It's not an instant feel good move, your body and soul have to adapt. It makes more of a dif. at 38 & beyond [because of the speed thing]. Fin length also contributes a little to being more narrow in general.

Again, just my experience.

[Than_Bogan]

That makes a lot of sense, Drago.  I think I may have corrected one "flaw" by moving DFT to factory.  From here, if I still have some trouble at the off-side finish, I'll plan to reduce length a bit.  Oddly, I've usually gone with non-trivially LESS length than the factory setting on my Goodes, but when I tried the factory length it felt awful, and longer felt better.  Still, I have some room to go back toward the factory length, which might prove to be the ideal settings for me.

Each time I do this I get a *little* more clue -- much of it from this message board!

[ForrestGump]

Drago, that is my thinking lately too. I am .050 less length, .018 more depth(to keep the fin ratio caused by shortening the length), and .045 back from stock on my ski(non goode). And it feels great.

My ski partner has his goode set up as follows: 7.004 length, 2.5 depth, .582 dft.  He's run into 41 off at 36mph.  On his we tried shorter and with more dft, but he keeps going back to long, deep, and way far back.