Boot cuff alignment.

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Postby Erik/BigE » Thu Jan 22, 2004 2:33 pm

I also found this detailed article: http://www.backseat.co.uk/cantingofskis.htm by John Gorman, who quotes Witherall alot.

Any opinions on this techhique?
Erik/BigE
 

Postby Mr. M » Fri Jan 23, 2004 8:03 am

Hi Erik,

An interesting article, especially from the historical prospective. I am not an alignment specialist, so my opinion might be completely wrong, but here it goes.

I think that there are few problems with the described template method.

1. The template has no means of providing a center boot position in the lateral direction during measurement. Just move your boot sole a little bit right/left relative to the template and the reading will change. Maybe these details are just not covered in the article or I missed something. Of course you may place a center mark on the boot and a center mark on template, but you?ll need someone else?s help to insure that you are standing on template correctly or you?ll need to look in the mirror while measuring.

2. The template measures the KPS (Knee Perpendicular above Ski) angle based on the front of the boot sole / knee angulations but what is really important is the boot heel angulations. The author mentions (and I also know it from reading the boot bindings installation instructions) that the bindings do hold by the boot heel. There must usually be a gap of about 0.5 millimeters between the front part of the boot sole and anti-friction device (AFD) of the binding. That is why the boot fitter places wedges under the heel. The author mentions that the measure result is independent of the floor or carpet type. So the measuring method is an indirect one (in case that that you are doing the real canting and not repositioning the foot inside the boot) and you cannot measure the final results of the adjustments. My conclusion is that the measure would have the same reading before and after any heel adjustments unless you shave the sole part of the boot the same way you do the heel. In other words, you can measure how bad the original boot fit is but you can?t measure how good it become after canting.

I think that the variation of this method might work well if you would be able to place the template foundation under the hill of the boot and measure the KPS angle while the front of the boot is on the floor and the heel is resting on the template. I can visualize such a device but it will be a little bit more complex than the described template.
Mr. M
 
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Postby Mr. M » Fri Jan 23, 2004 8:28 am

I have another question, which is not necessarily directly related to the main topic. I am a little bit confused by the method of placing the wedge under the boot heel or ?shaving? it. I believe that the boot / bindings interface has a very strict specs in respect to the heel geometry. Is it possible that modifying the heel you may affect the binding behavior and release values?

The only boot type I see on the market, which would allow for the easy canting adjustments, is Atomic. These boots might be not among the best in other categories, but they have detachable sole and heel peaces, which are screwed to the boot shell, so you may easily place the wedges between the boot and the heel.
Mr. M
 
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Postby tommy » Fri Jan 23, 2004 8:42 am

Hi Mr M,

I'm sure that if you modify your boot-binding interface, whether by wedges or any other means, you are on your own. The boot/binding manufacturers are not to be blamed if the gear doesn't behave to spec's anymore.

On the other hand, in order to do a 1degree tilt, you need only about 1mm difference in height (if I've done my maths correctly) and I suppose this isn't really such a big deal. For instance, looking at people at the slopes, not very many care to remove the snow from underneath their boots when they resume skiing after lunch etc, and the amount of snow that's stuck under is oftentimes much "higher" than the small increments/decrements resulting from wedging/shaving. But again, like anything else in life, I guess sound judgement and responsibility for one's own actions is what's needed.

cheers,
Tommy
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Postby Erik » Fri Jan 23, 2004 9:33 am

One place I know builds up the sole, planes it and then planes the top of the foot plate back to DIN specs so that it'll fit back into the binding properly. Should be easy with a table mounted router.

I've seen that some shops will carve out a notch in which to put the rubber heel pieces back in place too. Again a router would do this nicely. I guess that part matters on which shop you use.

The article I quoted seems to indicate that the shaving is on the opposite side to what I would have expected. Therefore, bowed legs would require that the inner side is shaved to bring the knee over the ski. But won't that cause stress on the medial ligament? (That's the one on the inside of the knee, connecting the shin and thigh.)

Cuff adjustment has an independent effect.

Anyhow, I'm still quite unsure about just how to make the cuff adjustment. I would think simply that if you feel any pressure on either side of the cuff when skiing on the flats that the cuffs are not positioned correctly. Yet, you could feel that the boots have not been canted properly either!

So, one has to rely on some sort of technique/measurement to do it. My idea (which is to center the knee to either side of the cuff) may be completely wrong, and instead a ruler should be used to ensure that the top of the cuff is equidistant from each side of the leg measured right at the boot cuff, with ruler parallel to the floor. That means that you need to ensure that the foot is centered in the boot with the buckles done up and you would certainly need help to do that.

What a big mess!
Erik
 

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