Idle Curiosity - effects of waist width

[jim_s]

So, with all of the great discussion I get to read on here about various boards, designs, techniques, etc, and my own seeming-predilection for skinny boards, I'm kinda curious what the real-world effects of waist width are. The ones I think I get include:

- binding angles (narrower=steeper, wider=shallower, shallower seems to generally be considered better, though originally being a skier, I find the side-to-side knee motion and forward-facing position of steeper angles more natural feeling)

- edge-to-edge transition speed (I guess one of my more favorite aspects of narrower boards, though I've read others who say their 20+cm boards transition as fast as skinnier boards)

- I'm guessing turn radius (ie, a narrower waist should give you a tighter turn radius, for a given nose and tail width, right? In that the board would have a deeper edge contour with a narrower waist)

- float in powder? (ie, wider would float better, I'm guessing... I'm clueless on this one, as I basically never see powder)

So, if anyone is willing, I'd be interested in learning more, just for the sake of learning more - I'm not likely to abandon my beloved (and skinny!) MK any time soon, no matter what is said. :-)

Edited March 20, 2018 by jim_s

[workshop7]

I don’t think waist width effects a boards turning radius.  If all other variables are equal, with the only difference between two boards being the waist width, the boards should make the same size turn.  This is assuming that the SCR stays the same and the nose and tail widths will change when the waist width changes.

One other ride characteristic that is effected by the waist width is the torsional rigidity.  This is a significant factor in how a board holds an edge.

Edited March 20, 2018 by workshop7

[jim_s]

4 minutes ago, workshop7 said:

Obviously, if the SCR stays the same than the nose and tail widths will change when the waist width changes.

Yeah, I guess that's where I was going - if nose and tail width were fixed, then a narrower waist (for the same length, nose and tail width) should result in a tighter side cut radius, right? (Now, I have no real idea if a, say, 25-18-24 board would ride any differently than a 27-20-26 board of the same length, aside from the good point you bring up about torsional rigidity. So, maybe this is a nonsensical question, if nose and tail width really have no absolute effect on the board - within reason, of course...)

I guess another difference I think I noticed (though I'm going back quite a few years to when I rode a wider alpine board) is that the narrower boards seem twitchier when riding flat, as in quicker to catch an edge, than a wider board. (I make a point of never riding the MK flat, except at the lowest of speeds, like super long shallow stretches, lift unloading, etc - other than that, Its always on edge - in part because that's what I ride for, and in part because it scares me to ride it flat, for fear of catching an edge and biting it hard - it seems to be very prone to catching an edge running flat, and/or getting kicked around by piles of crud, ruts in the snow, etc.)

[queequeg]

I would think that edge-to-edge differences aside, the biggest differences between narrow vs. wide for a particular rider are going to pertain to technique and body mechanics changes that result from higher/lower angles. Higher angles square your hips more towards the nose, lower angles less so. At higher angles your ankles function less to fine tune edge pressure/inclination, and more to shift weight fore and aft. On a narrower board my toeside feels more like my heelside than it does on a wider board.

Edited March 20, 2018 by queequeg

[MarkJeangerard]

- I was watching this the other day...

... and wondering if the fore/aft ankle flexion of a steeper stance might perform, to some extent, like the mono plate system does. (Looking at the wooden "hips" Sean has built.)

- In powder my 180 with 18.5cm waist is a dream. The 170 with 18cm waist... not so much. I always thought it was the length, more than anything. On the ultra soft surface of dry powder being too far over the nose or tail seems to be the majority of my troubles.

- Edge to edge. Narrow is certainly quicker in my experience. When popping crossover air between edges narrow vs. wide isn't going to feel a lot different. There is still the time it takes to move all your mass from one side to the other. But if you are doing deep, board stays on the snow - knees in the chest, crossunder turns I think you will notice a big difference. 

2 hours ago, queequeg said:

... At higher angles your ankles function less to fine tune edge pressure/inclination, and more to shift weight fore and aft. ...

- ^^ This is my interpretation of why it's easier to ride the board flat (catwalks and such) with a wider board and flatter stance. 

- With a steeper stance it's harder to hit people sitting to your front leg side with tail bombs while riding the lift. You have to really point your front toe straight down before you kick the waist. More often than not with stances above 65 I hit myself in the face with a wad of snow whilst I'm trying to nail people on my left. (I ride regular.) I even find that I have more accuracy in *which* of the chair riders I hit on my right if the stance is flatter. 

Edited March 20, 2018 by MarkJeangerard