Icon TT 80 -- binding position??

[ToddW]

memo to me:  first experiments with binding position on Icon TT 80 170cm tuned 0.5/3.0

After a couple months of weekly noncrystalline precipitation events and brown slopes (with or without a smattering of white), winter has arrived in VT and my rock skis have rotated to the back of my locker.

I spent 3 hours today on the Icon TT 80s trying out different binding positions.  They're the newer ones with powerrail adjustable in 4mm increments rather than the older ones with railflex and 15mm adjustment.  I was surprised how much of a Goldilocks story emerged (too much, too little, just right.) 

Today we had the sort of nice, crisp hero snow we usually get with temps below 0.  So these results are on good snow and groomers only.  No bumps, no ice, and nothing steep since coward me wanted to get a first read on the effect of binding position in friendlier circumstances.  I also spent the morning doing drills on kers supershapes to establish a baseline in my mind.

default position: produces nice turns when foot pull-back and early counteracting are working just right.  Tight brushed turns require some focus on these tasks or else medium radius turns result.  Any technique hiccough or laziness widens the turn.  I can't bend the ski as much as I'd like to; real g forces are just beyond reach.

forward 4mm: produces nice, tight turns even when movements are only 90% there.  Carved or brushed, the turns are just sweeter and tighter.  In brushed turns, the tails felt slightly loose but I'd been skiing supershapes all morning which is a bad reference point given their wide tail.  I hiked back up and examined the tracks of several short brushed turns where I felt this.  There were always two distinct tracks, so the skis were brushing and not skidding.  Skiing perception versus skiing reality again. 

forward 8mm: turned on some warning bells in my mind.  The tip felt oversized like a supershape ... and that's contrary to the ski's design intent.  It skis okay, but the tip is aggressive and I suspect the tails would slide on ice.

forward 12mm: yikes!  In the liftline, I sensed that the tails were light.  After about 20 turns, I stopped and reset the bindings to +4mm.  The tails were on the verge of switching to windshield wiper mode on short "brushed" (actually skidded) turns.  In lower energy carved turns they held with appropriate fore-aft working of the ski, but I wasn't interested in trying to push them harder and holding a yard sale.

forward 16mm:  I didn't try this, but it is basically what jbotti uses on his railflex binding.  I wonder if Head has mounted the powerrail bases more forward than they did the old railflex bases?  Or perhaps John's long femurs require a markedly different fore-aft setup than my short legs/long torso body.

to do next:  ice and bumps at -4, 0, +4mm.

(There's more that I can't remember right now, but this will have to do as a record since I have a 5 hour drive ahead of me and have to work tomorrow (MLK Day.))

[Johnny2R]

Sorry, I hope this doesn't take the thread off-topic - I don't think it does, really.

I posted elsewhere about ski selection for when hiring skis. When I read a thread like this, though, it makes me wonder whether I'm looking at the wrong criteria. If binding position really makes that much difference, I may well end up hiring great skis but with the bindings in the wrong position for me. Unless I can change the position myself, which I know some binding systems allow but probably not the ones used on rental skis, would I perhaps be better trying to find skis by manufacturers whose factory setup works for me? For example, I've really got on well with all the Dynastar skis I've hired, which may be because they were great skis, but may it also be because their typical binding position (slightly further forward, from a posting earlier in this thread) works better for me?

Is it possible to compensate for a sub-optimal binding position by a change in the way you ski (your own body position), or are you inevitably going to struggle if the binding position isn't right?

[LivingProof]

Johnny2R

Again, I've no knowledge of Europe, but, here almost all rental skis, and demo's, have binding systems that are adjustable. The one's I am most familiar with let the heal and toe be adjusted independently. You can check this when renting and verify the mid-sole marker on you boot lines up, or slightly ahead, of the ski center. Of course, if you have new snow, you may wish to have the adjustment slightly behind.

I think it's more fine tuning and a much larger factor is your stance and fore-aft position when skiing. Remeber - no weight on heels, feel the front of your shin always making very light contact with the liner.

[jim-ratliff]

Sorry, I hope this doesn't take the thread off-topic - I don't think it does, really.

Is it possible to compensate for a sub-optimal binding position by a change in the way you ski (your own body position), or are you inevitably going to struggle if the binding position isn't right?

Good question, and off-topic is almost always the case around here. I wouldn't call it a "sub optimal" position, but the binding position chosen by the factory may not be the best for all body types and sizes.  In Todd's case, he has several pair of skis and has his boots the way he likes, so he's trying the find the best match for this pair of skis.
It's fairly well accepted now that women need a more forward mounting position than men because of different body shapes and weight distributions.
And different manufacturers have different preferences.  In general, "Austrian" manufacturers seem to place their default mounting position more to the rear than the "French" manufacturers; and this can become part of a ski brand preference.  Someone used to Volkl (for example) that really works the front of the boot may not like the forward position of a Dynastar of Rossignol. 
There was a study done at SnowBird in Utah several years back that determined that most average skiers were most comfortable with skis where the Ball of the Foot (BOF) was over the Center of the Running Surface (CRS) of the ski. CRS is the midpoint between where the tip and tail of the ski make contact with each other when flat base to base (not sure what the equivalent measurement would be for Rockered skis).  But those same researchers went on to identify other factors that also affected the skier comfort and balance.

[ToddW]

For firm snow conditions, Head race skis (and race derived skis) are good at 1cm to 1.5cm forward of the default mark. I ski the TT80 1.5cm forward for everything but POW which I ski at the default mark.

for future reference, are your Head slalom skis mounted 1cm forward?  Do you know how HH recommends mounting them generally?

I skied JMD's pre-kers supershapes which are mounted 1cm forward earlier this season (while he tried my kers ones.)  It was noticeable, but not nearly as big an effect as I saw with the Icons yesterday.

[ToddW]

Unless I was racing, I wouldn't spend too much time trying to find the perfect spot for each set of skis.

That had always been my attitude.  Then I saw an emphatic post on the pmts forum stating

I guess I missed the memo about binding position and had them set up at the factory point. AACK! I literally couldn't ski. I'm thinking I'm rusty but dang these just aren't working. After being reminded to move the bindings up I ended up at +1.2 and they felt like old friends.

I knew that Chris B. initially had some fore-aft issues with the Icon, so I posted here to see what experienced, highly skilled skiers thought about their Icon 80s in case I too had "missed the memo." 

Thanks to jbotti, max_501, and everyone else who responded with their wisdom or experience.