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Binding mounting position for AT

post #1 of 9
Thread Starter 
I'm about to mount some AT bindings (Diamirs) on a new pair of 170cm Atomic R9.22's. They'll be used almost exclusively for back-country ski touring.

Just wondering about the wisdom of mounting them slightly (2cm?) forward of Atomic's recommended position. All comments here are based on using the manufacturer's boot centre mounting mark.

1) I have smallish feet (US 9). So, if I use the standard mark for boot centre, my foot will be further back than someone with a larger foot.

2) The Atomics have a very rearward mounting mark compared to some other skis I own and like (eg Bandit XX). Like 5cm further back.

3) I've read a lot about binding mounting position from Peter Keelty and others over the last few years - seems that on many skis the manufacturer's mounting mark may be further back than the ideal, possibly because they think the general public can't handle the extra tail length resulting from a more forward position.

4) Playing around with moveable bindings on my other Atomics (R10.20's) tells me I like the boot slightly forward of Atomic's recommended boot centre position on those skis.

So I'm seriously tempted to mount them a bit forward. Mostly just wondering if there are any AT specific factors I might have forgotten to consider...eg effect on traction while skinning, effect of skiing with a heavy pack, etc.

post #2 of 9
Wow, weird coincidence - I went through this exercise just a few months ago.
Executive Summary:
- yes, mount forward of the marking


I had previously been using Diamirs mounted on the older 9.22 version (i.e., kind of yellow/gold-colored, with a regular tail). They were still in fine shape, but then I picked up a pair of new R:9 (with the orange color and semi-turnedup tail) under unusual circumstances for about half the cost of what I could sell the old skis for.

The old skis had been mounted by the previous owner for a 25.5 boot, so my 26.5 boot put me about 5mm behind the midpt. Seemed to ski like it was a wee bit behind optimal too (although my opinion could of course be biased since I had already measured it).

New skis were the same stated length (170cm, just like yours), but the suggested mounting point was way (way, way) behind the older skis. Seemed like the midpoint mark had been influenced by the extra few cm of the turned-up tail, even though that has no effect on the running length of the ski.

Attempts to match up the ball of feet with the midpt of the running length put me so far forward of the suggested mounting point that I almost couldn’t believe it. So I did a measurement in which I intentionally biased every subjective aspect of the measurement so that I would be further back.

This still put me something like 3cm ahead of where Atomic said I should be. But it skis great.
post #3 of 9
Christchurch, what a beautiful town! Do you know Ed Willinger from the U.S. he moved there 6 years ago, he loves to ski. Anyway, mount those bindings forward by running a tape from tip to tail, then find the center of the ski by putting a tape on the ski, then mark that center point, then go 2 cm forward and mark that point. Set the boot on the ski check boot toe with forward mark see how it looks with respect to manufactures recommended mark, probably won't be much different. If you have a shop do the mount they should be able to do this, if they know what they are doing. Let me clarify; the center mark is the boot toe mark, then check to see boot center to manufacturer mark.
post #4 of 9
Why would anyone mount a pair of bindings that way rather that aligning the ball of the foot with the center of the ski’s running length?
post #5 of 9
thank you, Jonathan.
post #6 of 9
If you look at a binding jig you'll see a slot by the toe holes, this is the boot tip window so you can see your mark on the ski. Race skis rarely had marks indicating where they wanted you to be one the ski, it was up to the individual, so boot toe was measured to middle of the ski, honest.
post #7 of 9
Thread Starter 


OK, I took a deep breath and mounted the Diamirs 2.5 cm (~1 inch) forward of Atomic's boot centre mark. According to my measurements that's still at least 1cm behind Ball Of Foot over centre of running surface, but I felt like any more distant from the "recommended" mark was getting ridiculous.

The net result is pretty good - I feel very balanced and relaxed on the ski - something that I didn't feel with bindings mounted further back on a similar ski. I'm convinced that the 0 delta of the Diamirs tends to put your weight further back (especially in touring boots) so the forward mounting position helps compensate for this. I have never felt too far forward on the ski - even in powder there's no tendency for the tips to dive or catch. Occasionally in cruddy snow I've felt the extra inch of tail out the back, but only when I'm off balance anyway, so that is my fault. And the ease of turning and natural stance more than makes up for this.

Bottom line is this weekend I won a backcountry ski race on these skis, it involved a lot of hiking but also three 2000 ft high speed ski descents and they felt solid and stable at speed.

I'm convinced!
post #8 of 9
Nice to hear it worked out well, and congrats on the race victory!

As for the binding "delta," alpine downhill race bindings, in particular race-stock oriented setups, are actually moving toward zero delta since more angle on the binding/ski does not necessarily get the skier into a more balanced stance (i.e., hips centered over boots). But the right delta for an individual skier is whatever the right delta is for that skier's stance, morphology, and personal preferences.
Some interesting material here:
(Click on each logo and then scroll to the section responding to "What can you tell us about “delta” or ramp in bindings?" - one answer is: "The only thing that seems to be consistent about ramp angle is that it appears to be absolutely personal. There is no magic formula here. We have 9 USST athletes on Dobermann boots and each one is set up with a different ramp angle!")
post #9 of 9
Thread Starter 
Thanks Jonathan...and I'll definitely have a look at the binding delta reference.

As the years go by and I slowly start to understand my ski gear (it's only taken 27 years so far) a few things are becoming clear to me:

1) Most people (both buyers and sellers) have no idea of the number of variables involved in the selection and setup of their gear.

2) It takes years of semi-informed trial and error, or else a whole season off work with a wad of spare cash, to start to understand this stuff and how it affects your personal physiology and style.

3) I think that, for a lot of people, where they get to on the skiing skill scale is partly a matter of luck - of whether their equipment and its setup just happens to suit them or not. Most recreational skiers don't have the time, money or interest to get this stuff optimised. It's sad really to think that a lot of people could be having a lot more fun on their skis, if only they had a "personal skiing consultant" to work with them on gear selection and setup.

Data point - my partner is an intermediate skier. This year we changed the bindings on her skis from Diamirs (0 delta) to Looks (quite a bit of delta - I forget the specs). We didn't change the mounting position (it was already "forward of the mark"). She had always had trouble getting over the front of her skis and initiating turns.

What a transformation! - her whole stance on the ski has changed to being more upright, balanced, and natural looking, and her turns have gone from being one at a time tentative things to a flowing succession of linked arcs. She's also much happier riding the edge of the ski rather than skidding around on the tail.

Now some of this could be just the natural learning progression (a week in Valmorel at Easter probably helped too :-) but I'm convinced it's at least partly due to getting one more setup variable closer to correct for her.

That's what makes communities like EpicSki, and people like Peter Keelty, so valuable.

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