Ski size significance

[Lurdan]

Are there significant drawbacks to someone skiing on a 69" ski when they should be on a 66-67 and vice versa?

[KRoundy]

I can speak for the vice versa viewpoint. I'm a big guy (working on it) and when I use a small ski I basically overpower it. It drowns very easily in the turns and doesn't have the power I want to accelerate. I think if you have a too-big ski the opposite problem will happen. It will be difficult to turn and will ride very high in the water at speed. One benefit of a big ski is that it is easier to do deepwater starts (if you struggle with that).

[eleeski]

Things like binding placement and ski width matter more than raw length. I like a shorter ski with lots of width in the front.

 

But I've really enjoyed some skis that were too long for me.

 

Go longer if you are skiing slower and shorter for faster speeds. Rope length doesn't correlate to an advantage either way.

 

Often the manufacturer's recommendations are best. But try with an open mind to see what works best for you.

 

Eric

[Adam Caldwell]

The issue with big long skis is too much resistance to rotation. Imaging trying to ride a jump ski through a slalom course versus a trick ski. I believe @Horton can run 39 on a trick ski. Would like to see the same attempt on jump ski. The jumper with a much longer tail and controlling lever will take MUCH longer to rotate in YAW during the preturn then the trick ski.

 

The differences in performance of a 66 vs 68/69" ski are not much different at 32/34/36mph. A ski needs to be big enough to provide adequate 'lift' when ski is in sliding laterally, but also short enough in length such that the 'resistance to rotation' as the skier is traveling outbound off the second wake is not excessively high and will allow the skier to have the ski in the right position when the ball arrives.

 

Making a successful pass isn't necessarily ALL about speed, power etc. Its about having the ski in the right position at the right time. What I describe as the 'rates of rotation' need to be 'right' with the ski setup & skier vs. ski size match-up.

 

Big picture that means the ability to have the ski pointing across course as the ski is coming back through the backside of the buoy. For example, I can be nearly 80 feet up course of the ball and outside the buoy line. But if I cannot get the ski to rotate and be pointing back cross course by the time the ball arrives, then I will end up on a LATE path after the ball. Conversely, I can come into the turn only 10' upcourse, but already have the ski rotated and ready to go, and get back on and EARLY line in a much shorter distance.

 

This is where the ski design/setup define techniques. You're potential on the water is limited to the skis rotation rates and stability characteristics.

[Lurdan]

@adamhcaldwell If I understand you properly approaching the ball you have to yaw enough tip in the water to engage enough rocker at the critical moment of the turn to get the ski pointed across the lake. A long ski will obviously resist this attempt to yaw, but it can be overcome by some degree with setup, say having a longer leading edge on the fin? I had to read it through a few times to feel like I understand and I want to be sure I have it correct. And by lift do you mean a ski that is at an angle relative to the flow of water will want to lift out of the water but the fin stops it from shooting "horizontally" out of the water?

[Adam Caldwell]

@Lurdan- yeah, your on the right track!

 

Basically under your feet exist a magic spot. The hydraulic center of lift. Its like is a three dimensional pivot point that the rest of the ski is rotating around. There is some amount of slip in all planes, which will impact the overall attitude of the skis pitch, roll, and yaw.

 

If the ski is too stable in one or more of those dimensions of motion, the turn will suffer. Basically we use the wetted surface of the ski, the fin, and the wing to control these rates of motion.

 

Controlling the 3 dimensions of rotation on the way out to apex is very critical. Its easy for a set-up to become over-stable in one way or another and kill the skis ability to be in the right place at the right time when the skier arrives at the ball.

 

Whats interesting is that yaw can help ski turn when riding flat, but doesn't do much once the ski banks up during the reach. Meanwhile, pitch does not make a ski turn when running flat, but is a big part of how the ski turns after the ski starts to roll up moving into apex.

 

Being able to separate those characteristics in your mind will help when trying to decipher what fin adjustment/boot adjustments to make in order to increase or decrease a particular "rate of rotation" in the ski to dial in the skis 'timing' within the constraints of the course.

 

[Ski_Dad]

@Lurdan - I'm certainly no expert on ski sizing but is cost a reason you are not switching to the correct size ski ? - what 69" ski are you sking now and at what weight and speed ?

[Lurdan]

@ski_dad oh, no! I used to ski on a 2015 radar senate as a college student cost was a big factor and it was cheapest. I just picked up a 2018 67" Connelly GT I was just curious if the change from 69 to 67 would be a really stark change. I have a feeling that the workload will be more intense as the senates tend to ride high in the water, plus the ski is long so it rode even higher. I just want to know as much as I can so I posted the question!

[Lurdan]

@adamhcaldwell do you mind elaborating on the fourth paragraph? I understand yawing more tip while riding flat will turn the ski. You're engaging more rocker against the flow of water, diverting your direction of travel. But it doesn't when the ski is on a knife edge, like rounding a buoy? For instance if the water is breaking behind your front foot and you yaw more tip so the water breaks ahead of your front foot would it not turn the ski in a tighter arc because you are engaging more surface area ahead of that 3 dimensional sweet spot? Along the same lines with pitch. Pitch alone will not turn a ski when riding flat but how does pitching forward on your ski when on your turning edge? I guess my lack of insight with pitching on a turning edge stems from the fact that pitching on an edge, both cutting and turning is completely foreign to me. I can't really visualize the body mechanics of pitching forward on an edge, it just doesn't compute with me.

[Adam Caldwell]

@ Lurdan. Yes it will Yaw in the water. But that doesnt make the turn. The pressure on the bevel starts to impart a pitch moment that creates the a banked turn.

 

Yes, some YAW is going to happen, but if you have too much of that after teh ski is rolled up moving through apex and finish, then youll just dive the nose and blow the tail.

 

Think about it like this..... the only way a ski could "rotate and turn' if the bank angle was at 90 deg is via pitch rotation.Its not pitching forward. Its the tail moving away from CL and the tip moving back toward CL. YAW will stuff the nose/blow the tail, and you cant roll it up any more. Forget the idea of carving...not a real thing.

 

Focus on what the ski is doing behind the feet(behind the pivot) not so much about what the ski is doing in front of it.

[Lurdan]

@adamhcaldwell Oh! you're putting more pressure on the front of the ski so the tail can more freely smear to point the ski back to the wakes?? Sorry for basically repeating what you say back to you I just want to be sure I fully understand.

[Adam Caldwell]

@Lurdan

 

Correct.

 

 

[Horton]

@adamhcaldwell 39 off at 20 mph on a trick ski is pretty easy. 41 is a nightmare - I have not gotten to 3 ball in years. The whole problem is speed management at the end of the turn. If I ever practiced I think I have a new idea I want to try.

 

Feel free to click "Off Topic"

[B_S]

It's not so much the size that matters; it's how you use it (er, so I've been told...).

[75Tique]

I wondered about length in my recent search, but there is a lot bigger difference between a 67 and a 69 than 2 inches, which by themselves probably wouldnt make a huge difference. But here is roughly the same ski (I say roughly because they are not the same age and I am not sure how much the design would have changed through the years, but look how much bigger the 69 is compared to the 67. That's a whole lot more ski to push through the water.