SkiJay

Why LE Matters @rfa Anything that moves the fin’s center of pressure matters, this includes both LE and DFT. In the book Fin Whispering, I went to great lengths to isolate individual ski behaviors so each behavior can be tuned without affecting the others. In this case, DFT is very important as LE-neutral DFT moves are essential when isolating smear changes. With the WhisperFin, my focus is on making ski tuning as easy as possible by boiling fin adjustments down to two simple moves—back and forth, and in and out of the ski (no LE-neutral DFT moves here). The downside of this simplicity is that both of these fin movements affect multiple behaviors. When I made the statement that "DFT isn't a measurement I worry much about. I'm more focused on how DFT affects the fin's leading edge location (LE) ...," it was in the context of WhisperFin tuning. And what I was implying was that of the two behaviors affected by a simple forward or backward fin move, I’m more concerned with how the move affects LE because the goal of these moves is to adjust yawed tip engagement to be as deep as possible without leading to tip-grab. Let’s consider a forward fin move for illustration purposes. Moving the fin forward increases both LE and DFT. As LE moves forward, we’ll get more yawed tip engagement from our habitual inputs, which leads to more smear, tighter turns and more cross-course angle. As DFT moves forward, the fin loses some leverage (shorter moment arm between the bindings and fin) which also leads to more smear. It’s a happy coincidence that DFT’s affect on smear is complementary to the goal of getting more tip engagement with a longer LE. Reducing fin area by moving the fin up into the ski also increases smear. In fact, reducing FD by .010” increases smear six times more than an equal .010 DFT increase (an updated topic in FinWhispering—2nd Edition). Accordingly, I consider fin area changes to be primarily aimed at adjusting smear, and back and forth fin movements to be primarily aimed at adjusting yawing tip engagement. This further explains the context surrounding my statement that "DFT isn't a measurement I worry much about. I'm more focused on how DFT affects the fin's leading edge location (LE) ...." Finally, to help illustrate why LE impacts yawed tip engagement, let’s use a little exaggeration. The fin on a ski is like the feathers on an arrow. With the feathers at the very back of the arrow, it will be very stable in flight. The further forward you move the feathers up the shaft, the less stable the arrow will be (meaning the easier it will be to deflect the arrow from its path). If the feathers were to move forward past the halfway point, the front of the arrow would swing around and become the back. Similarly, with the fin at the back of the ski, the ski is very stable and just wants to go straight down the lake. The skier has to force the ski to lay over on its side to turn or cut cross the course. The further forward the fin is on the ski, the less stable it is and the easier it is for the skier to deflect it from its natural path (force it to turn and cut). If the leading edge of the fin goes far enough forward, eventually the front of the ski will spin around and become the back of the ski, tip-grab in the extreme. If LE is too far forward, the skier’s habitual inputs will yaw too much tip into the water and the tip will bite. If it’s too far back, it’s becomes too hard to keep enough tip in the water to complete turns well or to generate enough cross-course angle. In short, the fin’s leading edge location (LE) matters a lot.

One of us is the smart handsome one with mad skiing skills. The other one is ... me.

I attached a ski handle to the ceiling above my elderly mom's bed so she can use it to sit up in the morning. When she gets all situated with the handle and is ready to sit up, with a tiny little voice she says "hit it" and does a shaky sort of tumble-turn that ends with her sitting upright on the edge of the bed with her feet on the floor ?

@pcmcon729, The WhisperFin is fully adjustable. You can make it turn nice clean round turns or quick snap turns, depending on how you set it up. What most skiers find from the generic setup (before custom tuning) is that their turns are slightly tighter, and noticeably easier to initiate and finish with the WhisperFin. And contrary to appearances, this fin is very low drag. The holes in a standard fin create a tremendous amount of drag. The bands of laminar flow across the low pressure side of this fin generate noticeably less drag than holes. Less drag delivers quicker acceleration from the same skier effort. Because I'm travelling so much and have no fixed office or staff, processing returns is not something I can handle right now. Perhaps you can split the cost of one fin with a buddy. The chances of one of you buying out the other are pretty high. And worst case, this limits the downside if you both decide to sell it.

@skialex, So long as you look at any setup as a starting setup that you will then customize to best meet your personal needs, then you'll probably end up in much the same place regardless of where you start. That 65" setup is a good starting setup for a finesse skier. But I'd move the bindings forward at least 1/2" from there for a 66" ski. Better still, I just got done helping a 32 off skier on a 66" evo, and this is where we ended up: 29.625, 7°, 2.510, 5.748, 1.935 (LE=7.683).

Question: Does a softer ski allow a more forward front boot? —@coach3, It depends what part of the ski is softer. If the tail is softer, then yes. But your Lithium Vapor is likely not any softer than a ProBuild, and if it is, not materially so. I've done some comparison testing between the Lithium and the ProBuild Vapors, and found the Lithium to be remarkably close to the ProBuild in both performance and feel. I have no doubt that both will run solid -39s in competent hands, and that both will give you a pretty equal fighting chance at running full 35s.

Ha! Yup, all the time, @Andre. Then I come to my senses and just go skiing :D

@FLeboeuf, the smaller you can run the fin without the tail feeling slippery at the finish of turns, the easier it is to keep the tip low through turn finishes, straight into the cut. So I'd experiment with less fin area before going back with the bindings. And if you're not experiencing any tip grab, you want to move the fin forward too. So if you go 1/8 turn shallower (on FL and FD to keep the index marks level) then also move the fin forward 1/8 turn. If there's no tip-grab, keep moving the fin forward until the tip starts grabbing, then move back. This will give you the fastest ski possible.

@Anthony Furmanovich, Yes the website numbers work well with the Pro Build on down. But don't accept them as perfect. Try a little tuning based on the instructions that came with the fin. We all ski differently.

@jercrane, No need to get discouraged. If it's not working, there's a reason and it can be sorted out. First, the ski is a symmetrical hull. If it turns great on your offside, then it is proving that it's capable of turning at least as well on your onside. So the issue is mostly one of technique. If you got used to forcing a standard fin around onside turns with your back leg, then the same amount of force will overpower the WhisperFin even more. You'll likely adapt to using less force within a few sets, but that's not the goal here. Using your back leg to turn onside turns is a habit that will limit your future progress, so regardless of your fin choice, this habit needs to change. The new habit you want to cultivate is one of moving your hips inbound from onside turns more ahead of your ski while riding mostly on your front leg. Free skiing is the perfect place to work on this by doing lots of whips. Try to initiate turns on both sides by getting well up over your front foot. Then ride that front foot, proactively moving your hips inbound out of each turn—inbound, up and forward to the handle. Moving your hips aggressively inbound from the ball will take care of the wheelies. ). If you are feeling exposed to going OTF on your offside, move the fin back .010" or until you don't feel so exposed while riding tall over your front foot. If you're only feeling exposed to going OTF on your onside, it's probably because you're forcing the tail of the ski past the angle you want at the finish of the turn, into form-crushing hockey stops. The Whips drill will help tremendously with this.

@jercrane & @C5Quest, I've just updated the starting setups at FinWhispering.com by supplying two setups for a couple of popular sizes—one I've headlined as "Nimble," the other as "More Supportive." Just like the standard fin, one setup will never be a silver bullet for all skiers. If you are light for the ski, or if you are a finesse skier, the nimble setup will be the best place to start. If you tend to force the tail around onside turns with your back leg, or if your tip engagement tends to be more yawed than pitched, then the more supportive setup will be a better starting point. If you start with the nimble setup, and find the tail feels a bit slippery, go straight to the more supportive setup and tune from there. This binding-forward small-fin concept ups the ultimate performance of the ski. But taking advantage of this expanded performance envelope requires more finesse than a standard fin. Think "riding the ski" vs. "forcing the ski." An F1 car is more nimble than a stock car, and even the best stock car driver will need to adapt to how little "horsing" the F1 car will tolerate before he stops spinning and starts carving turns at higher limits.

Yes-ish @Anthony Furmanovich I have fins for all brands of skis in stock now. Blue Radar fins are backordered for about 10 more days, but I have bronze fins for the Radar and both colors for all other skis in stock now. Have a great trip!

@C5Quest, The furthest forward I've seen bindings on a 66" Vapor is 29.75". But like you said, it's a very personal thing. If you move further forward than that and can still get crisp tight turns by reducing fin area without the tail getting too slippery at the finish of turns, then you have a setup worth considering. If you can run your best passes with it, then it's a winner. DFT isn't a measurement I worry much about. I'm more focused on how DFT affects the fin's leading edge location (LE), which is a function of FL + DFT. So to answer your question, the longest DFT's I see are on very shallow fins for light kids or VERY smooth adults. Example: A good LE on a 66" Vapor is between 7.690 and 7.710. If the fin is shallow, say 2.460, matching the index marks will give you a FL of about 5.710. Since LE = FL + DFT, then DFT= LE - FL. In this case: DFT = 7.710 - 5.710 or DFT = 2.0". I think 1.960" is the longest DFT I've seen on a 66" Vapor so far.

WhisperFin Success Story: Yesterday, 15 year old Sophie Hunter, set two PBs in her first two sets on her new WhisperFin. In her first set, she ran 3 buoys -22@34 mph. Her next set she ran 5 balls at -28@34 mph, twice back-to-back. That is nearly a two full pass improvement in one day! Congratulations Sophie!

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Hahaha! ? When your fin order came through with your name on it, @paul413ski, I figured your buddy refused to give your fin back. That's happened a couple of times now. Thanks for letting him try it ??

DFT Insights @paul413ski & @Ed_Johnson, Thank you for sharing your experience with this simplified tuning method here. I'd like to expand on how DFT affects these setups. Since this method is guided by using the index marks to keep the fin "level" to orient the teeth with the water flow during acceleration, there are no LE-neutral DFT adjustments. All DFT changes move the fin's leading edge location (LE). So two ski behaviours change with each adjustment, yawning tip engagement and smear. Of the two behaviours, yawed tip engagement is most affected. The further forward LE moves, the more yawning tip engagement we get from our habitual skiing inputs—all good for increased speed and power until we've gone too far and the tip starts grabbing. But as DFT gets longer, smear also increases. So while the tip is getting more bite, the tail is also loosing some grip. This loss of tail support further increases exposure to tip-grab. Because of this dual behavioural effect, the search for the longest LE our technique can use will also need a little more fin area to control the increasing smear. Fortunately, FD changes affect smear over six times more than DFT changes do. So as you zero in on your max LE with DFT adjustments, you may want to throw in a few small LE-neutral fin area adjustments, where you reduce DFT by the same amount as your increase to fin area for a slight LE reduction (e.g. an increase of a 1/8 turn to fin area (FD & FL) would be accompanied by a 1/8 turn decrease in DFT).

Hi @block, If 3/8" forward made the ski turn like a bus, it's too much. If you have Mikro-Just, move back 1/4". If you can't move your bindings in small increments, then move the bindings back to where you started and use fin area to settle the tail down. And you shouldn't need to make "several turns" of the adjustment screws. A 1/4 turn is about .010". At this point, you may want to record where you are, then reset the fin to the generic setup to see how you like it now that you're more up to speed in the season. You can then tune from there again if necessary. If you're really happy with how the ski is behaving now, disregard this whole post. I may be misinterpreting your explanation.

JMac very graciously agreed to let me post this video of his first set on the WhisperFin. It's 39 off (10.75 m) at 36 mph, after some winter time off, on the generic WhisperFin setup. I'd like to point out two things in particular. Note how far up the tip the water-break is indicating good solid front foot pressure. And check out the smile at the end of the pass. Jason McClintock on the WhisperFin

@jimbrake, You're doing the right things for the right reasons. The goal with seeing how smeary it will get is to settle on something that feels (and looks on video) dependable and supportive most of the time. If/when you dunk more tip into the water than intended, there should be some over-smear into a little too much angle, but not enough to end your pass. A setup like this allows you to drive a lot of tip into the water to smear a really tight turn when scrambling—without spinning out. If you often get a slippery feeling at the end of turns with only moderate scrambling, add fin area.

@Ed_Johnson, You can also make it super stable by going deeper and back. It can accommodate a very wide range. If it's not behaving predictably and inspiring confidence, it's not yet fully dialed in.

I'm just guessing here, but I bet she's 100 lbs. Lighter than you, @Ed_Johnson ?

@Sprayblaster, You asked if these fins are delivering PBs for anyone. Meet 12 year old Megan Spelkey. Megan had been working hard to run -28s. She put a WhisperFin on her ski a week ago and has since run a series of PBs. Yesterday, she skied into -35 for her first time ever.

@C5Quest, Moving the rear binding forward isn't critical if it's difficult to achieve. But I recommend moving the rear binding as far forward as possible at all times. The only exception (which I still don't like) is to help onside turns by giving the back leg more power. But this is a crutch that compromises ultimate performance. @skialex, Goodes like this fin. Three Big Dawgs have them, with Bruce Dodd setting a national record on his XTR. Even if you've not had a good experience moving forward on Goodes in the past, moving forward with this fin won't be the same experience. And even if you don't like how moving forward feels or works, you just have to run the fin a bit larger than it's run on other skis. Even run at FD = 2.600, the WhisperFin is WAY smaller than the standard fin, making it easier to keep the tip down through the transition into an earlier cut. Plus you still get the low drag benefits.

@ktm300, The rocker does affect binding location from ski brand to brand and model to model. And for the most part, moving forward of where you normally sand with a standard fin is well within the adjustability envelope—i.e. no where near what most skiers do with their technique while skiing. Goode ski models with a lot of rocker, wide forebodies and narrow tails allow for less forward binding movement before tip behavior gets compromised, D3 and Radar are happy as far forward as I've ever been able to go ... unless the ski is too small for the skier in the first place. So yes, this forward movement is ski and technique dependant. This is why the instructions recommend exploring how small you can make the fin by moving forward before you 1) run out of forward binding movement, 2) the tail gets too loose at the end of turns, or 3) an issue with tip behavior crops up—like feeling exposed to OTFs through the wakes. And on the third point, I'll also say that feeling exposed to an OTF at the wakes can also be a technique issue, where the skier's COM and feet are not moving past the rope early enough in the crossing. When moving the bindings forward is no longer an improvement, simply move back 1/8" and increase fin area until the ski smears into ideal angle for the cut.