Boot ramp angle and the combinations that work!

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Boot ramp angle and the combinations that work!

Postby h.harb » Wed Apr 03, 2019 10:00 pm

This is a public notice about ski and boot combinations. Be aware if you buy a Look binding with a Rossi or Lange boot, or a Marker combination with a binding, you will be dealing with a negative or very low a ramp angle. A negative or low ramp angle combination is when the heel of the boot is in a low position relative to the toe, compared to heel higher than toe relationship. In the experience I have with skiers over the last 20 years it is evident that this type of set up for the majority is in question. We find with our skiers a negative or low ramp is a detrimental set up for fore/aft balance. For most skiers, and I mean 98% of all skiers deal with fore/aft balance issues, this negative or lower ramp angle thing is not helpful and doesn't bring easily balanced situations in skiing.
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Re: Boot ramp angle and the combinations that work!

Postby AnI » Thu Apr 04, 2019 1:11 pm

I can totally relate to this Harald's post. I can even add to it that for some people, like myself, one has to go to the top end of the range of binding delta angles. In combination with Raptor, I need 6-7 mm of delta to feel comfortable on skis in the fore-aft sense, and possibly could benefit from 8 mm, but I have not found such bindings yet. My anatomy, including long legs, is without doubt a strong contributing factor which may be putting me on the top end of the range of available deltas. My relatively big boot size (I am in size 29.5) is another factor, I need a larger delta in mm for the same forward tilt in degrees. One of the indicators of losing balance to the rear which I had periodically (until I figured out how to fix this with proper selection of bindings) was black toe. Subjectively, it was occasional loss of balance to the rear which was strong enough to register as such. I learned from experience that for me, personally, two types of bindings work well:

1. Knee Binding which has a specified delta of 6 mm (which can be adjusted down with steps of 1.5 mm by purchasing a kit from the manufacturer). I have these bindings on my midfat and powder skis and on my son's powder skis. He is also a tall boy, almost teenager by now, and seems to benefit from a significant delta. The advantage of Knee is that they do not try to fix what ain't broken and have not changed the delta in years. It is always the same 6 mm, out of the box.

2. Tyrolia PRO 11 bindings, manufacturer's part number 100510 from one of the past years, with 7 mm delta. I bought two pairs of these bindings when I saw them on sale, for future use. The trouble with manufacturer like Tyrolia / Head is that they may change the delta from model year to model year. It is hard to find the spec for the current model year, or even know for sure which model year you are buying. I had a discussion with Diana about it. Even she complained how complex this (potentially) ever changing delta can be.

I never had black toe and never had a feel of losing balance to the rear when I skied skis with these bindings. However, I had worse experiences with other types of bindings, and had to replace them. I swapped PRD bindings to Knee bindings on my Jam with great success. I swapped bindings on my TT80 to bindings which are compatible with the rail installed on the skis, it increased the delta somewhat but these bindings still do not work well enough in terms of fore-aft.

It is very interesting to hear from Harald that high delta benefits 98% of skiers. There is a web site, which its author calls "The Skier's Manifesto", in which he promotes zero delta angle. I kind of suspect what Harald would say about that site, so I am not promoting it, just stating for the record. I found a few interesting things there, but I had my doubts about zero delta. I was always curious, though, if there is a possibility that dependence of fore-aft balance on bindings delta is not a linear but could have optimum values at both ends, at very low or negative delta, and at higher positive delta. Harald's post shows that it is not the case. The number of 98% implies that it is very rare, probably only for people with certain anatomy, that delta close to zero or negative can work acceptably or be beneficial.

I was amazed how sensitive the fore-aft balance is to a small change in binding delta. It is like night and day difference. And this difference makes it so much more difficult when it comes to buying new skis and picking bindings for them. Having said that, my other observation, from personal experience, is that it takes time to get used to the balanced position. Increase of delta may lead to unusual impression of being too far forward, with subsequent compensation with the upper body which takes away all the benefit. This compensation seems to happen totally automatically. Higher delta does not replace drills on fore-aft to get used to the feeling of being in balance, which usually feels like being quite a bit forward, even though in reality it is just a centered position. I do not know what HSS experience is, my thought that one can improve someone's fore-aft with heel lifts only to a certain degree. Beyond that, drills on fore-aft are needed, time to get used to a new position is needed, and this process may take several iterations. It is comfortable to sit on the toilet :)
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Re: Boot ramp angle and the combinations that work!

Postby HighAngles » Thu Apr 04, 2019 10:22 pm

Harald's warning should be heeded by all skiers. I never experimented with the ramp/delta angle until this season and now I'm wondering what took me so long. I wish the equipment manufacturers would make it easier to test these adjustments. And, as noted, binding manufacturers should make it easier to know a binding's delta information. We have numbers on our skis, it wouldn't be hard for them to include the stand height number on the toe and on the heel.

I have found that I'm quite sensitive to delta changes in my testing this season. As little as 1mm change is noticeable and there is definitely a "sweet spot". Of course everyone has their own unique body morphology so there isn't a one-size fits all solution, but I have a short BSL which makes this an even more critical concern.

Note that some binding types make it difficult to impossible to change the ramp angle. So you must consider what approach is right for you. That could be using the same binding on all of your skis and dialing-in your needed fore/aft alignment only at your boots. Or you may need to adjust some of your bindings through the use of shims to gain consistency across all of your skis. I have had to go that route and it can be quite challenging depending on what skis/bindings you have (and how many for some of us!).

But make no mistake, if you have wildly different deltas across your skis, this will impact your skiing. Some may say that they can easily adapt in a run or two, but are they really optimized in their fore/aft alignment then? Why make skiing at a high level even harder by ignoring this important variable?
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