Ski flex, tip rocker & bumps

[Slim]

I am close to you in size (6’5”, 175lbs) and like to think of myself as an advanced intermediate. ;-).
I have spent most of my ski time the last few years learning to ski moguls.

I would warn that for learning to ski moguls you want a ski that is:

• -Short (but this is at odds with your height and desire for stability in deeper snow and at speed)
• -Forgiving if you end up in the backseat. You will end up there, and being able to keep moving and recover is key.
• -Releases smoothly and easily from the tail (but this is at odds with strong carving), the last thing you want is your tails hanging up on the bump behind you.
• -Easy to pivot on flat bases. When you are learning you likely want to ski moguls slowly, Pivoted turns slow you down, carved turns build speed.
• -Either quite tapered or simply not to wide at tip and tail. Wide tips catch the side of moguls, leaving your boot hanging in mid-air.
• -Tall rocker at the tip, in case you end up running straight into the side of a mogul, it will ride up and over, rather than augering in.

The Volkl Kendo get good marks for moguls, but that is for easier, uniform moguls and advanced skiers. They are also rated as more of a firm snow ski despite their mid-wide waist and rocker.

 

[markojp]

You've described the RTM 84 nicely. (other than the big tip rocker... that part I'm not so on board with. )

 

[Slim]

You've described the RTM 84 nicely. (other than the big tip rocker... that part I'm not so on board with. )

@markojp , I believe from previous posts you are an instructor, right? So you have good technique.

I am sure the big tip rocker part is not needed for good mogul skiing technique.
But for us bumblers, I have found myself, especially when I was starting to learn to ski moguls, occasionally aimed straight at a steep sidewall of a mogul. This made me afraid of the impending crash. Fear doesn’t help to ski better. When I switched skis with my friend, I noticed his skis (taller tips, maybe softer tips too, otherwise same length and width) would simply ride up and over the sort of bump that would have stopped me dead with my own skis.

So just to be clear:
I am not saying you need lot’s of tall tip rocker to ski moguls, but I am saying that when you are learning, that feature provides,let’s call it a “safety net”, in case you screw up.

 

[LewyM]

@markojp , I believe from previous posts you are an instructor, right? So you have good technique.

I am sure the big tip rocker part is not needed for good mogul skiing technique.
But for us bumblers, I have found myself, especially when I was starting to learn to ski moguls, occasionally aimed straight at a steep sidewall of a mogul. This made me afraid of the impending crash. Fear doesn’t help to ski better. When I switched skis with my friend, I noticed his skis (taller tips, maybe softer tips too, otherwise same length and width) would simply ride up and over the sort of bump that would have stopped me dead with my own skis.

So just to be clear:
I am not saying you need lot’s of tall tip rocker to ski moguls, but I am saying that when you are learning, that feature provides,let’s call it a “safety net”, in case you screw up.

I think what you are talking about is less about tip "rocker" and more about softness of flex. A softer flexing ski will be more forgiving in the bumps when technique is less than stellar. Stiffer requires more precise engagement and provides less margin for error or just slamming around.

 

[Slim]

I think what you are talking about is less about tip "rocker" and more about softness of flex. A softer flexing ski will be more forgiving in the bumps when technique is less than stellar. Stiffer requires more precise engagement and provides less margin for error or just slamming around.

I absolutely agree in general, a softer ski will be more forgiving and easier in the bumps.

What I was talking about was a specific situation where your tip is aimed at a snow wall rising steeply up. In that case, only rocker will help. Imagine you are on a 1x4 piece of lumber. Super soft, but the flat tip will simply auger right into the snow wall, and all the flex in the worrld won’t help you at that point.

 

[Monique]

I absolutely agree in general, a softer ski will be more forgiving and easier in the bumps.

What I was talking about was a specific situation where your tip is aimed at a snow wall rising steeply up. In that case, only rocker will help. Imagine you are on a 1x4 piece of lumber. Super soft, but the flat tip will simply auger right into the snow wall, and all the flex in the worrld won’t help you at that point.

This also works for logs. Ask me how I know ;-)

 

[LewyM]

What I was talking about was a specific situation where your tip is aimed at a snow wall rising steeply up. In that case, only rocker will help. Imagine you are on a 1x4 piece of lumber. Super soft, but the flat tip will simply auger right into the snow wall, and all the flex in the worrld won’t help you at that point.

That isn't how skis work. All skis have a turned-up tip. . . always have. Although shape and flex are interrelated, in this case you are mistaking the effect of rocker with the effect of flex (particularly in the fore body of the ski).

The question is when you hit that bump, how easily will the ski flex into the contour of the terrain. A stiffer ski, or a ski that the particular skier is unable to flex effectively, will give you the experience you are describing because the ride is non-compliant. The ski will feel "flat" and 2x4ish. A softer ski will flex more easily into a pattern that will allow you to address the terrain feature (in this case a mogul). . . essentially bending so that the tips go up or around. To @markojp's point, this isn't really about "rocker" profile, although a deeper rocker profile will allow you to spin and pivot more easily which does have some utility in the bumps - but that is a different topic and has more to do with tactics and line.

If you are aiming your skis directly at a "snow wall" (or more likely, what you are describing is jamming your tips in a hard trough below the bump) there are other issues to address.

 

[Slim]

That isn't how skis work. All skis have a turned-up tip. . . always have. Although shape and flex are interrelated, in this case you are mistaking the effect of rocker with the effect of flex (particularly in the fore body of the ski).

I am sure you are right and flex is the most important. But not all skis have the same amount of rise in the tips. Here are two examples, 20mm and 80mm rise respectively. There is no way that the ski tip that’s practically flat on the snow rides over a (steep) snow wall as well as one that’s 80mm above it.

If you are aiming your skis directly at a "snow wall" (or more likely, what you are describing is jamming your tips in a hard trough below the bump) there are other issues to address.

Absolutely, those issues are technique. I wasn’t talking about doing it purposefully, but by accident, which is why I figured Markopj doesn’t experience it. (And thankfully I have less and less of it too)

 

[cantunamunch]

I am sure you are right and flex is the most important. But not all skis have the same amount of rise in the tips. Here are two examples, 20mm and 80mm rise respectively. There is no way that the ski tip that’s practically flat on the snow rides over a (steep) snow wall as well as one that’s 80mm above it.

You are talking about initial approach angle. That's a valid concern - but in this specific case, if there is a high pressure point in the forebody of the ski the higher approach angle would just fold the skis back more. In other words, I think putting OP on skis with similar flex and similar running length in front of the binding would give OP similar balance problems, no matter what the rise angle was.

 

[Slim]

You are talking about initial approach angle. That's a valid concern - but in this specific case, if there is a high pressure point in the forebody of the ski the higher approach angle would just fold the skis back more. In other words, I think putting OP on skis with similar flex and similar running length in front of the binding would give OP similar balance problems, no matter what the rise angle was.

I agree, my discussion with @LewyM was about hitting a mogul, not about the issue the OP described in piles or soft snow.

 

[Mendieta]

I agree, my discussion with @LewyM was about hitting a mogul, not about the issue the OP described in piles or soft snow.

Yes, I moved all of this discussion to this new thread. Done with that, thank you!

 

[cantunamunch]

One thing OP's list did not include is a concept along the lines of 'enough stiffness in the ski that minimal deliberate edging has good control authority' . Am I alone in noticing that?

TBH I've only ever seen one post expressing that sort of sentiment, @epic was talking about some Hot Rod-era Nordicas on the old site.

In other words, all the items in OP's list point to a buttery noodle. What defines the other side of the envelope?

 

[Slim]

One thing OP's list did not include is a concept along the lines of 'enough stiffness in the ski that minimal deliberate edging has good control authority' . Am I alone in noticing that?

TBH I've only ever seen one post expressing that sort of sentiment, @epic was talking about some Hot Rod-era Nordicas on the old site.

In other words, all the items in OP's list point to a buttery noodle. What defines the other side of the envelope?

Are you calling me the OP? The OP was @sky_chicken.
But, since my post is now the top of this new thread, I’ll assume you are talking about my post up above here.

I think you are correct in saying that I was defining the forgiving side of the envelope, and there could and should be another side.
I disagree that I was defining a soft ski. A ski could have all the points I mentioned and still be very stiff. But you are right, even if it was stiff, it would still not be a precise carving ski, or a crud buster etc.

The reason I wrote that list was that @sky_chicken was asking for a ski to use out west, including starting to ski bumps, and many skis recommended were skis that would not be very easy for someone to start out skiing moguls on.
The factors I listed are ones I am sure of making a positive contribution to a beginner mogul skier.
There might, or might not, be a requirement for a certain amount of torsional stiffness, but I wouldn’t know, so I didn’t mention it.

 

[cantunamunch]

Are you calling me the OP? The OP was @sky_chicken.
But, since my post is now the top of this new thread, I’ll assume you are talking about my post up above here.

Yup, your post is now lead; none of what I post here after the split is meant to refer to thoughts from @sky_chicken 's thread.

I think you are correct in saying that I was defining the forgiving side of the envelope, and there could and should be another side.

I am asking you (and whoever else feels like doing it) to add to the list...

There might, or might not, be a requirement for a certain amount of torsional stiffness, but I wouldn’t know, so I didn’t mention it.

 

[James]

What's your ski pictured with the low angle tip? The other is a Rossi Soul 7?

I think I agree with you on the tip, but that's not rocker. There are skis with very low tips. The quite old K2 Mach 1 slalom ski, the several yrs old Rossi CS or x ? 80.

Things could be worse, it could have a square low tip and be stiff in the forebody.

 

[cantunamunch]

There are skis with very low tips. The quite old K2 Mach 1 slalom ski, the several yrs old Rossi CS or x ? 80.

Dynastar Legend MR; Palmer PO2 ; Maxel GS Storm ...

 

[Slim]

What's your ski pictured with the low angle tip? The other is a Rossi Soul 7?

I think I agree with you on the tip, but that's not rocker. There are skis with very low tips. The quite old K2 Mach 1 slalom ski, the several yrs old Rossi CS or x ? 80.

Things could be worse, it could have a square low tip and be stiff in the forebody.

Yes, Soul 7.

The top ski is my kid’s 149 cm K2 Pinnacle 85 Jr, I was just using those two images to illustrate my point that there is a huge variety in tip rise.

You are correct, Tip rise is not the same as rocker. Those Pinnacle Jr have a very deep rocker line, but not much rise. Rise could come from rocker or just from the curve of the very tip(like old XC skis). I should have just called it tip rise.

And then, as @LewyM mentioned, soft plex in the front of the ski probably matters as much as tip height.

 

[James]

I don't know why on "normal" skis they make tips that are very low. I get it on downhill or super g skis. But otherwise, it seeslike a silly reinvetion of the wheel when we have a perfectlyfine selection of rims. I mean the Mongolians figured out the tip curve thousands of years ago.

That said, an extended gentle curve on a tip like that Soul 7 does have it's effects. It may go over things easily, making beginning mogul skiing easier, particulary on large soft western bumps. The disadvantage is it takes that much longer for feedback from the tip. What's going on? It can lead to a vague feeling. It's not exactly conducive to quick feedback.

I remember the first time I tried a tip like that. It was some Scott ski, maybe the P4? We'd switched skis up on the top of Lone Peak at Big Sky. Not so smart... Anyway, you enter the turn and, wtf? where's the ski?? I started a turn, and it said "oh yeah? Wait a moment, I'm busy" Wanted to through it in the woodchipper. We actually did switch skis half way down, me back on the Stockli VXL (a truly great ski).

 

[jack97]

I am close to you in size (6’5”, 175lbs) and like to think of myself as an advanced intermediate. ;-).
I have spent most of my ski time the last few years learning to ski moguls.

I would warn that for learning to ski moguls you want a ski that is:

• -Short (but this is at odds with your height and desire for stability in deeper snow and at speed)
• -Forgiving if you end up in the backseat. You will end up there, and being able to keep moving and recover is key.
• -Releases smoothly and easily from the tail (but this is at odds with strong carving), the last thing you want is your tails hanging up on the bump behind you.
• -Easy to pivot on flat bases. When you are learning you likely want to ski moguls slowly, Pivoted turns slow you down, carved turns build speed.
• -Either quite tapered or simply not to wide at tip and tail. Wide tips catch the side of moguls, leaving your boot hanging in mid-air.
• -Tall rocker at the tip, in case you end up running straight into the side of a mogul, it will ride up and over, rather than augering in.

A competition mogul ski has similar traits you mentioned.

1. Forgiving since it has a stiff tail where if you get in the back seat, you can lever or pry yourself back up. The boot mount is close to the center to add more tail length as well.
2. No tail catch, twister mogul skis has 98-66-85 dimension, the tail is extremely narrow. I have and seen skis with even more narrow tails!
3. The lesser shape dimension gives one the option to carve the beginning part of the turn or to pivot it.
4. Wide tips, IMO is a bad thing to have when learning to aim at the target of the upcoming bump. Having narrow tips allows room for error.
5. Moguls ski have a flex pattern where the tip and front part of the ski is designed to be softer. That way you can bite into the snow by front loading the ski. The other is by pressing the tips into the face of the mogul, that can slow you down as well.

Bumps comes in all shapes and sizes, sometimes those troughs have really narrow corridors, that's where having a wide stance can lead to "altitude splits". IMO by going to a narrow ski it's less cumbersome to adjust the stance to a narrow one. If you have wide skis adjusting to a narrow stance to fit that narrow trough requires very little error. It can be done and I have seen former competitors ski with wider skis but their techniques are already honed in.

 

[cantunamunch]

I don't know why on "normal" skis they make tips that are very low. I get it on downhill or super g skis. But otherwise, it seeslike a silly reinvetion of the wheel when we have a perfectlyfine selection of rims. I mean the Mongolians figured out the tip curve thousands of years ago.

Talking of -ahem- vintage tip designs, something about this tip design really tweaks my brain in a good way. That said, tips like that are complete PITAs to wrap steel edges around ...and they can act as sprung loads in vibration events (as some of us may remember from the early days of rockered design).