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what is the right ramp angle and forward lean anyways? - Page 3

post #61 of 71
Here is a better image that shows the Triangles that are formed and calculated (providing I have this correct. Steve?).

Note the base of the orange triangle is measured from the horizontal position of the instep to the big toe. The height of the triangle is 95% of the belly button height(true height not pictured here). The D line is 7/10 back from the metatarsal as described earlier in this thread. Then ramp the angle of the new triangle until the top point is horizontally over the D line. That is the desired ramp angle for that size of foot and COM height(according to this theory anyway).

The math I brought earlier uses 1/3 instead of 70% for the D line. So adjust accordingly, IF it even turns out to be the correct math.

Hope the images help

I think the fundamental theory here is that the instep point noted with a circle is the natural balance point of our body to provide BOS for the COM when standing evenly centered on the foot, regardless of where the knees are or the flex in the ankles. Tilting the ramp forward a bit moves that BOS balance point to a place that may be more effective for skiing, just behind the balls of our feet.

Also note that there is something else not depicted in this image which is a triangle showing how the heel is related. Its confusing for the purpose of calculating ramp angle. But imagine a triangle connecting C to B to a new point F under the heel. That is the natural standing tripod supporting our BOS with the balance point at the instep. I say tripod because there are also three points on the bottom of the foot(heel, big toe side, little toe side).

(note the ramp angle is exaggerated in this image because the height of C is not the true height of the belly button. If the triangle were its true height, it would require much less ramp angle to hover the tip of the triangle over the D line.)
post #62 of 71
BTS, thanks so much... that is really useful, and I think you have it right.

I think the reason is actually different, though. The dynamic forces applied in skiing require the neutral point to be slightly different so that our bodies are "moving forward" during skiing instead of being "behind" the skis. Perhaps that is a different way of saying what you did, but I think of it this way: moving that point forward has our bodies natural responses acting to our benefit instead of fighting the movements that are most effective for skiing.
post #63 of 71
Makes sense. now the next question I have is how do I measure the boot's inner ramp angle? Or is that documented somewhere for boot models?
post #64 of 71
Somewhere on here in a post of mine to Bud I explained how I measure boot ramp and binding ramp with a digital level. If you can't find it let me know and I'll go through it again. Boot ramp is not listed by manufacturer. I doubt they even know what it is.

post #65 of 71
Originally Posted by race510 View Post
Born to ski. I think you will find (assuming you have more than one pr of skis) that it will work better to just get bindings set to zero ramp and work independently with boots.

well since i have several pairs of skiis already and won't be changing soon, I sorta gotta work with what I have. One pair had 10mm of heel lift on the bindings and plate..yikes..that is being fixed now but they tell me they can only get it down to 2-3mm difference because of the ski binding plate which has built in forward ramp. Ok, so I will make due on that ski until the next skis. In any case, I would like to know how you would propose to change the ramp angle in the boots? I already have canting plates on the bottom of the boots, etc. Not trivial to consider adding toe lift to the boots either. I t would actually be way easier at this point to tweak the binding ramp, but let's see how off I am before jumping to that conclusion. If its only a small amount I can slide some strips of duct tape in between the bottom of the boot and the screwed on canting plates and possibly deal with things that way.

At this point I am just going to follow through with making my skis as flat as possible and letting my boot guy do whatever he thinks he needs to do in terms of straightening my boots(already done)...and this will have to be a learning experience. But I am going to measure the boot ramp angle so that I know what it is, and measure myself so that I know what my optimal ramp angle overall is supposed to be according to that system, perhaps make some adjustments to my current skis..and ski for a while to see how it all feels.

In the future, I can see a lot of benefit to doing as you say

1 - Make sure all skis are flat (more universal for using other people's skis)
2 - First adjust zeppa angle in any new boot I get to the ideal angle for me before even putting the boots on for fit.
3 - Potentially adjust forward lean also after first fixing boot ramp

In my case I have lots of problematic foot fit issues that work against me. High instep, large achilles, large lower calf, one foot significantly wider than the other(and both kinda wide), one foot significantly longer than the other, very limited dorsiflexion, etc. In my case, pretty much all boots out of the box block my heel from touching down all the way and getting an even tripod on the bottom of my foot...totally aside from the ramp angle issue. And actually there are only a few boots I can even get my feet into at all. Next time mayebe we'll try to cram me into a plug boot but they are typically so far off it would be difficult at best.

So in some ways I kind of have to deal with all of that stuff so that my foot at least can sit in the boot and feel the whole bottom of the boot, then think about the ramp.

Thanks for the tip about digital level. I'll try that.
post #66 of 71
Adjusting the boot ramp depends on the boot. Most (but not all) allow you to pull the boot board and grind the top of it. Note, however, that most of them these days aren't flat, so this will change the character of the bootboard. David didn't like the "kick" at the front of some bootboards (I don't remember what he called it) where the bootboard curves up under the toes. He said that it triggers the toes to think that the foot is rolling forward when it's not, so the muscles fire reflexively at the wrong time. He encouraged me to take that out of my boot boards.

Anyway, you can grind some of the ramp out this way. If you can't get enough, you can use thin cork (available at Home Depot) to layer on the bootboard and grind the angle more and more flat as you add them. The downside of this is that you want to be mindful of the impact to fit across the forefoot (and, frankly, all of the boot).

Keep in mind, too, RicB's description of how to get the boot to press your foot down against the floor of the boot through the use of added foam on top of the instep. Given the fit changes resulting from boot ramp, this may become required.
post #67 of 71
I'll just discuss it with my boot guy if I decide to try to change the boots. That sounds scary. I'm a software guy.
post #68 of 71
The kick up at the toe is called toe spring and I agree it is better removed if possible.

One of the easiest ways to remove boot ramp, but it will also decrease forward lean is to add toe lifts under the boot. As they come in different thicknesses it is possible to use a thicker one at the toe than the heel. Or even to use none at all in the heel.

Still it is preferable to work with your skis and get them all flat. The binding you are talking about with 10 mm height diff, heel to toe I assume is a Look. Still it sounds high to me. There is a shim under the heel that can be removed. You will be nearly flat. Adding a shim under the toe will then level you entirely.

VIST has shims available that I would think you can find. Bud will know more about what is available in the U.S. than I will. Anyway it should be possible with a little creativity to get any binding flat. If you can't find them locally I can send some out.

post #69 of 71

Lou, I am up to a 9mm shim plate on the toes of my Slabs with nothing under the heels and using Salomon bindings, which as you know are one of the flatter ones on the market, and still feel like this boot could use more (not much but more). Have you had any experience working with this boot? I am about ready to go back to my old boots....

post #70 of 71
I have very little experience with the boot, but agree there is too much ramp in them. Up here Rossi has the lions share of the race market I would say, probably followed by Nordica with Tecnica doing great with their new boot.

Unfortunately one of the things I am always wrestling with is how to get safely between athletes and coaches. Generally it is difficult to make recommendations until the coaches have seen their athletes perform on their new equipment each year. After that it is possible to recommend changes when there are problems, but it certainly is more difficult than with recreational skiers.

Generally the rec skiers I work with are adults and not under the same pressure as the kids. They have the time to experiment and can more easily explain the differences they feel.

It is why I think it is so important to try and conduct research that can be published and taught to coaches and instructors. It gives them more support when making decisions about equipment that may be second guessed by parents and it lets them get the results faster without experimenting.

post #71 of 71
I share some of your same frustrations. For the most part the coaches are not trained to assess alignment issues in their athletes or just choose to ignore it. Though I have offered to train some race programs' coaches or do an assessment day with their athletes, I have had no luck with them taking me up on the offer.

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