Why symmetric mounting on fatties?

[raj]

So I used a reasonably fat 180 cm Karhu Jak/ Mothership (127-97-117) as my everyday ski on Mt Hood this year. I haev skinnier skis but wanted to see how a fat ski works in every condition, so have skied on these every day all season. They obviously work fine in powder/ crud/junk and are fine on groomers with more angulation. The only place they start feeling sketchy is on steep/ spring ice as in before it corns up. I used them on the Wy'east Face last week and they were down right dangerous.

So to get more bite, I put a small lifter on them (changed form Rossi Scratch flat binding to look lifter with 7 mm lift). That definitely helped without hurting anything in the soft. Still they don't feel as safe as my 85 mm skis on steep bullet proof (duh).

That got me thinking of old fat/ powder skis which used to be mounted asymmetrically. The binding was mounted closer to the inside edge by say 5 mm so you would get much better edge hold without worsening powder performance.

I have never mounted/ skied with such an asymmetrical mount but it seems to make a late of sense for a fat. So what am I missing? Anyone skied a modern fat that way and thoughts. I just wanta pair of moderate fats that are versatile every day. One could argue why not use the right ski depending on the condition but in the PNW cascades, you go through everything in the same day and sometimes on the same run so versatility is important.

[soul_skier]

the problem with that is if you take a rock to the edge on one, you can't swap it out to make it the outside edge.

[addict]

I haven't tried it on new fat boards, but on old fatties asymmetric bindings never felt good. Don't know if it's me but there seems to be more pressure on the wide edge, making them feel unbalanced and unnatural. Plus on hard pack going fast, trying to rail both edges feels downright squirelly and nerve wracking. Not sure about jaks, but I find edge hold and stability in a 110mm waisted ski just fine up to moderately icy conditions. Super icy, I go elsewhere, but I would on thinner skis too. Theoretically there should be no difference, you just have to angle a little faster to get the same edge bite. I don't think the torsional stiffness of the jak is that high, maybe that's the problem? Or get a ski like the G4 for spring, which should have edge hold and still enough float/strength for pow/crud.

[The Dad]

Speculation on the downside: In soft stuff, uneven resistance would tend to knock your knees together, while on packed, the greater distance on the outside would tend to raise your inside knee.

Speculation on the lack of upside: It might have made sense when skis were not as torsionally rigid, so you needed your binding close to the edge to carve a turn. But improvements in same have made it possible to carve on fatties.

[raj]

Thanks guys. Makes sense. I remember trying the Wizard exploders a few years ago and not feeling sketchy. Explosives are only slightly narrower than Jaks so the comment about torsional rigidity is probably key. The other thing is that explosives have less sidecut and I think I like that on steeps. Moderate lift (5-10mm) as on my look lifter seemed to help, so I will keep that.

So I guess recipe for next year for me is going to be stiffer fat+ less sidecut+ moderate lifter. Looks like stiff 179 Bros were the answer all along

[fluffballs]

shane mounts his pontoons duck footed, makes since becuase it's a more anatomical posistion, more powerful. Who stands, squats, jump or even runs with their feet pointed straight ahead? With wider skis we now have the option of kicking our toes out. I'd love to try it.

[summit]

shane mounts his pontoons duck footed, makes since becuase it's a more anatomical posistion, more powerful. Who stands, squats, jump or even runs with their feet pointed straight ahead? With wider skis we now have the option of kicking our toes out. I'd love to try it.

Old bump but this is particularly interesting...

[BakerBoy]

shane mounts his pontoons duck footed, makes since becuase it's a more anatomical posistion, more powerful. Who stands, squats, jump or even runs with their feet pointed straight ahead? With wider skis we now have the option of kicking our toes out. I'd love to try it.

That's why the entire line of Fischer race boots and freeride boots are duck footed. Sorry for the paid spray, but the Soma Tec in Fischer boots really eliminates any reason to mount skis duckfooted, and is quite noticable while using them. Essentially, it drops the center of your heel back to the center of the ski, and shifts the forefoot to the center of the ski. It takes a couple runs to get used too, but having the center of your entire foot over the center of the ski is definitely something that you can feel. Asymetrical mounts are a crutch to poor ski design and technique, and Fischer boots take it one step further by perfectly centering your foot over the center of the ski.

Oh, and they have replaceable toe and heel lugs, so you don't have to buy new boots/pay a tech to reface them when they get worn down, like Salomon boots.

[Sinecure]

I had an asym snowboard way back when. A few companies still make them. I wonder if we'll see asym skis. Or maybe we already have and I missed it?

It would seem to me when you get to Pontoon width it migh make some sense to put more sidecut into the inside edge than the outside, but I'm not an engineer, and have never even played one on the interwebs. Hmmm...

[BakerBoy]

I had an asym snowboard way back when. A few companies still make them. I wonder if we'll see asym skis. Or maybe we already have and I missed it?

It would seem to me when you get to Pontoon width it migh make some sense to put more sidecut into the inside edge than the outside, but I'm not an engineer, and have never even played one on the interwebs. Hmmm...

Done and gone with Elan, many years ago. It really just doesn't work out in principle as well as it might sound on paper. Especially nowadays with wide waists, where the point is to be more 50/50 on your skis than the 90/10 (ish) that asymmetrical mounts force you into.

[mntlion]

some tele skis (G3?, scotty bob) have assym skis.

I mounted girlguides work/fats last year with a 2' duck mount to help her knee pain (she walks duck footted) pain was gone in a day..

Also nordica aggressor boots are similar idea to the fischer (pivot from the heel not the mid foot I think) she is going to ski the nordicas this year, with a normal mount and see if that works for her.

[El Chupacabra]

That's why the entire line of Fischer race boots and freeride boots are duck footed. Sorry for the paid spray, but the Soma Tec in Fischer boots really eliminates any reason to mount skis duckfooted, and is quite noticable while using them.

BB - what's the fit like on the Fischer boots? overall volume, heel pocket snugness, width, etc... Haven't heard much about them.

I don't fit in any Langes, or Flexons/ Kryptons (all too narrow). Tecnica fit me very well, but the exaggerated forward lean tires me out. Now back to an undersized Salomon Xwave 9, which I think is packed out enough to be tolerable (last 10 days of last season were painful); flex is good (might soften it a bit though), lean is good, heel pocket could be better.

[BakerBoy]

BB - what's the fit like on the Fischer boots? overall volume, heel pocket snugness, width, etc... Haven't heard much about them.

The MX line of boots is medium volume in the forefoot, with a fairly snug heel pocket. It's reinforced by the shell, so it's only going to pack out so far. I skied on the MX9 last year (http://www.fischer-ski.com/en/produc..._product=14649) and enjoyed it 98% of the time. It wasn't quite stiff enough to really power out of backseat landings, but this year there is a new line of freeride boots called the X-line. The X-Fire http://www.fischer-ski.com/en/produc..._product=14646 is their lowest volume freeride boot (race fit), and it's definitely low-volume throughout, but still has a medium width in the front (which was the problem I had with other boots; race fit, but not quite wide enough). The MX and X-line both have a very upright stance, which I prefer.

[summit]

BakerBoy: Those sound like exactly what my foot needs. I need new boots to replace Nordica Beasts and since Nordica is on boycott status...

How heavy are fischer boots? Nordicas are horrendously heavy (13.5lbs for a 26.5).

How do they fit on the instep?

[nick > jesus]

after learning about the new race boots this summer at hood, i am pretty sure i would like to be in their plug this year pending the fit

[Huckwheat]

I know raj is already convinced, but my first thought with the assym mount, would be the loss of power to my outter edge. I think my outter is just as important as my inner edge......I would hate to lose leverage on it.

Also, I am surprised you think 85 is more stable on crunch steeps than 97. I am most confident on my explosives, due to the bit of width under foot (never worry about the boot-out feeling).

[Toby]

<epicski>I would worry it would make me drop my outside ski too far back and my hips/bum too far into a turn. I like to drive my outside ski forward through a turn in more of a straight stance, GS-style. I like my ski tips roughly equal, square on to where I'm going.</epic>

[marshalolson]

reply to the original question...

basically back in the day when people were rocking the asymm mount, when the expert skis were long and stiff, people used a totally different technique to ski them. you were not on edge for a long period of time like you are in a modern carving turn, and the majority (all) of your weight was on the downhill ski, thus you wanted the asym mount to be quicker edge to edge and make the ski easier to roll over for a brief period of time.

however, if you are standing on egde and driving a ski 60/40 like modern technique dictates, then you need to be mounted in the middle of the ski so you can carve on the uphill and downhill ski.

edit: and re: the riser plates - most think a riser on a fat ski is dumb.

here is my reason why:

the whole reason for a riser is to increase leverage on the edge. on a fat ski, you have a ton of leverage already from the width of the ski. if the ski is 100mm, you have effectively 50mm^2 of leverage (gross simplifications taken. pechel- this is prolly very wrong, so feel free to fix it - reallistically, if the ski is 100% torsionally stiff, it would be 100mm^2 and 10mm of effective lift from a 5mm riser, but whatever). by pythagoraus, with a 5mm riser, 50^2 + 5^2 = 50.24mm^2 or 1% more leverage.

basically the idea is that you are adding weight, adding damping that reduces the feel of the ski, and changing the flex pattern of the ski for no real improvement in leverage.

[Glisseur]

shane mounts his pontoons duck footed, makes since becuase it's a more anatomical posistion, more powerful. Who stands, squats, jump or even runs with their feet pointed straight ahead? With wider skis we now have the option of kicking our toes out. I'd love to try it.

Duck stance sounds good in theory, haven't tried it myself yet but sure will this winter. A friend of mine who makes Hendryx skis (hand made Swedish custom boards) have experimented a bunch with it and swears by it as the next thing in skiing. Makes even super wide waists carve on groomers he says. Makes sense, with a normal, straight position you have to roll the inner foot sideways to edge the ski. With duck stance you just push forward with the inner foot and knee and the ski rolls up on the edge. At the same time you get more pressure on the inner ski moving you towards a 50/50 weight distribution, something that's key when skiing super wide skis in pow to get maximum flotation and control. Another benefit is that your knees are positioned in a more natural and stronger position.

Hendryx Voodoo Child mounted duck:

[El Chupacabra]

The MX line of boots is medium volume in the forefoot, with a fairly snug heel pocket. It's reinforced by the shell, so it's only going to pack out so far. I skied on the MX9 last year (http://www.fischer-ski.com/en/produc..._product=14649) and enjoyed it 98% of the time. It wasn't quite stiff enough to really power out of backseat landings, but this year there is a new line of freeride boots called the X-line. The X-Fire http://www.fischer-ski.com/en/produc..._product=14646 is their lowest volume freeride boot (race fit), and it's definitely low-volume throughout, but still has a medium width in the front (which was the problem I had with other boots; race fit, but not quite wide enough). The MX and X-line both have a very upright stance, which I prefer.

Thanks -- I'll go check those out at the shop.

[Dexter Rutecki]

Hendryx Voodoo Child mounted duck:

Why do skis called Voodoo Childs have Purple Haze printed on them?

And that mount scares the hell out of me. It would be funny to ski them the wrong way (until you hurt yourself).

[Glisseur]

Why do skis called Voodoo Childs have Purple Haze printed on them?

Because I'm stupid and can't read properly That guy's doing a lot of funky custom stuff with just a few topsheet options, that might actually be some other ski than it was intended for. Who cares, they look über cool and my main point was the mount. It looks funny as hell but apparently works.

Heard Seth Morrison mounts his skis with a duck stance as well, not just McSchlonkey.

[summit]

For duck footing, it seems the Fischer duck boots make more sense than a duck mount. That way you don't have to remount when you mess an edge and you don't have to custom mount all your skis.

[funkendrenchman]

Because I'm stupid and can't read properly That guy's doing a lot of funky custom stuff with just a few topsheet options, that might actually be some other ski than it was intended for. Who cares, they look über cool and my main point was the mount. It looks funny as hell but apparently works.

Heard Seth Morrison mounts his skis with a duck stance as well, not just McSchlonkey.

Way off topic, but do you still have that green Norrona jacket for sale?

[pechelman]

the whole reason for a riser is to increase leverage on the edge. on a fat ski, you have a ton of leverage already from the width of the ski. if the ski is 100mm, you have effectively 50mm^2 of leverage (gross simplifications taken. pechel- this is prolly very wrong, so feel free to fix it - reallistically, if the ski is 100% torsionally stiff, it would be 100mm^2 and 10mm of effective lift from a 5mm riser, but whatever). by pythagoraus, with a 5mm riser, 50^2 + 5^2 = 50.24mm^2 or 1% more leverage.

basically the idea is that you are adding weight, adding damping that reduces the feel of the ski, and changing the flex pattern of the ski for no real improvement in leverage.

great, ive been singled out as the local enginerd.

but since you asked..
Unless Im missing something, the benefits seem to be a bit more on the torque\leverage side of things than 1%

Ive always though of stack height vs width as a leverage ratio.
Assuming we have a 100mm ski and a 25mm stack (height from edge to binding) that would be a leverage ratio of .5
ie 25/50

Now say we mount some freerides on there 34mm right?
Well whatever, lets just say its a stack of 35mm for round numbers.
so then 35/50 = .7

Thats roughly a 40% improvement in the force you have to apply from your boot to generate the same force at your edge. Or take it the other way, 40% less force you need to generate to counteract the edge forces.

For a physical demonstration, grab a small allen\hex wrench.
Assume the small stubby side is the lever arm produced by the geometry from your boot to the edge plane\base, and the larger side is the lever arm procuced from the edge of the ski to the centerline (ie right under your boot).

Now flip it the otherway (drastic extreme I know) and there is the difference.

/techno babble


edit: oh and duck mounting looks freaking weird. Id imagine that since most manufacturers are utilizing triaxially braided fibers (ie +45/-45/0) that would serious F^CK the flex pattern of the ski. You are now adding an asymetric force to that laminate along one of the fiber bias angles which would most definitely cause the ski to warp. You probably wouldnt visually see this much in a physical demo due to the majority of the stiffness coming from the core (maybe not?) but Im fairly certain this would induce a good bit more shear stress to the sandwhich of core\rubber\butterfinger\chocolate\fiberglass\tops heet laminate.

edit 2: and what does duck mounting do to release characteristics of bindings as now a longitudinal ski flex induces some lateral shear at the bindings