New Posts  All Forums:Forum Nav:

Delta angle

post #1 of 29
Thread Starter 
Hi,


I recently measured the delta angle of my Marker bindings and it is only 1mm now, thanks to a lifter under the toe. I plan on adding a second lifter to raise the toe of the binding more. This would result in a negative delta. Anybody played with a negative delta? I don't plan on anything too dramatic, only 2mm or 3mm of negative delta. What would be the results of a negative delta?
Using a negative delta i am trying to achieve two things: i want to reduce the ramp angle and also the forward lean of my boot. I know i could add the lifter under the toe of the boot, but i live far from any real bootfitter. Adding a lifter under the toe of the binding sounds like a simple solution.

Thank you.
post #2 of 29
I have been using a toe raise/lifter for my race boards (many companies do this esp for SL). The result is that the shovles hook up rather quickly & make skidding harder...on my all-mtn & crud skis I run a positive angle to make bombing & bouncing w/o hooking easier. It also depends grealty on your boot size. Bigger boot /longer sole less impact...my size 9 squeezed into a size 5 (285mm) = noticable difference

PJ & Todd @ racestocksports.com can give you all the support you need
post #3 of 29
Quote:
Originally Posted by alu
Anybody played with a negative delta?
I did. Back in about 1997 or 98 when we were experimenting with short hypercarvers and extemely high, partially DIY plates. I tried plates higher fore than aft but don´t know anymore if the resulting angle of plate + binding was also negative.

Afaik, there have always been race plates with negative delta (Rossi had them though his standard retail plates were "highly positive", the Marker plate is traditionally negative by 2 mm). It helps eliminate too much height difference in some bindings and the theory I heard was "more pressure onto the forebody".

IMO, it´s highly individual and has to be tested. As ips writes the final angle also depends on boots, both the sole length and their ramp. Taking their forward lean, flex, and the skier (height, weight, strength, body levers, technique) into consideration there are just too many variables to give a recipe.

I wasn´t happy with the 55/51 mm ratio on my GS skis in combination with Lange L10, later RL1 zc 323 mm and my 185cm/85kg=190 lbs. No problem skiing free on most slopes but couldn´t be forward enough in gates on steeper courses, especially when it´s very cold. I finished using 47/55 mm. With softer boots (zb) and/or better technique it may be less - would have to try.

Another issue are different skis. You might need/prefer different angles on the SL/GS/SG/allmountain/freeride/... skis.

Warning: this is 301-stuff, or a (double) black diamond post for experts. No basic reading.
post #4 of 29
Quote:
Originally Posted by alu
Hi,


I recently measured the delta angle of my Marker bindings and it is only 1mm now, thanks to a lifter under the toe. I plan on adding a second lifter to raise the toe of the binding more. This would result in a negative delta. Anybody played with a negative delta? I don't plan on anything too dramatic, only 2mm or 3mm of negative delta. What would be the results of a negative delta?
Using a negative delta i am trying to achieve two things: i want to reduce the ramp angle and also the forward lean of my boot. I know i could add the lifter under the toe of the boot, but i live far from any real bootfitter. Adding a lifter under the toe of the binding sounds like a simple solution.

Thank you.
From my understanding, the ramp angle is the angle of ankle flex inside the boot, and the range of motion it moves in, which can not be changed by raising the front of the binding. Raising the front of the boot will change the angle of the boot cuff to the ski however. Only speculating, but maybe this difference is why Checkracer had trouble getting forward racing, after reducing delta angle.

You might want to try reducing the ramp angle inside the boot (easier said than done), thus opening up the ankle some. This changes the range of motion the ankle is operating in. I've been told that @ 2.5 - 3.25 is the range that works best for most skiers. Through experimenting on myself with guidance, I found this to be true. After this would be the time to reduce the forward lean in the boot shaft.

From my experience of the last few years, reducing forward lean needs to be accompanied by a reduction in ramp angle or our balance may be affected negatively, and we end up compensating in some way. What I also found out, is that a little goes a long way. Hopefully some of the boot pros will help you out. Later, RicB.
post #5 of 29
Thread Starter 
Thank you for your answers. Testing is probably the best way to find out what works for me. I was just trying to understand how it works. Again, i am trying to reduce the forward lean (especially the lean) of my boot.

RicB, IMO reducing the ramp angle actually locks the ankle a bit, but i am not a boot expert.
I find very interesting what you said about the angle of the cuff changing in relation with the ski. That's what i am trying to do. I hope that if i raise the toe so it is slightly higher than the heel (2-3mm or even 4), the forward lean will decrease. So instead of raising the toe of the boot i am trying to raise the toe of the binding because i don't have access to a REAL bootfitter and i can do it myself. It's way easier than to lift the toe of the boot which mean finding the right piece of plastic and the right screws etc.

Please keep the info coming.
post #6 of 29
Quote:
Originally Posted by RicB
...You might want to try reducing the ramp angle inside the boot (easier said than done), thus opening up the ankle some. This changes the range of motion the ankle is operating in. I've been told that @ 2.5 - 3.25 is the range that works best for most skiers. Through experimenting on myself with guidance, I found this to be true. After this would be the time to reduce the forward lean in the boot shaft.
RicB,

Hmmm ...as I understand it, Ramp angle is the angle of the boot board inside the boot in relation to the bottom of the boot that in combination with the angle of the cuff create the angle for the ankle.

Wouldn't reducing the ramp angle in the boot actually close the ankle (assuming the boot shaft was left as is)? Assuming the relationship between the ramp angle and the cuff are right for range of motion of the ankle (and no other fit issues exist), wouldn't lifting the toe be simpler to bring the lower leg more upright and maintain the ramp/cuff angle rather than start mucking with the fit inside the boot?

On the other hand, if the forward lean of the cuff has the ankle closed to the point of effecting ankle motion, I would think that making the cuff more upright would help and reducing the ramp angle (by itself) would make it worse? Either way, lifting the toe would not help since it does nothing to change the angle the ankle has to work in.


Quote:
Originally Posted by alu
Using a negative delta i am trying to achieve two things: i want to reduce the ramp angle and also the forward lean of my boot.

Alu,

Why are you trying to achieve these two things? There are some good boot fitters on here (I'm not one of them!!!!!) and maybe this additional info would help them help you.

My experience is: I have a lift under the toe of my boot, I don't recall how thick it is, but what I have (or anyone else) isn't relative to you anyway. The same lift under different length boots results in different angles. I started as you have (actually a boot fitter did this first), by raising the toe of the binding. One thing to consider though, if you have multiple skis you have to do this to all of them, if you demo skis you won't be able to shim them. If you adjust the boot, it will work for any skis you click into. Note however, that different bindings also have different delta angles.

My (simple) understanding is that delta angle is the angle the boot sole sits on in the binding, ramp angle is the angle the foot sits on in the boot in relation to the boot sole, and changing delta angle does not change ramp angle (and vice-versa).

Chris
post #7 of 29
Thread Starter 
cgeib,

Thanks for the answer but the problem is that i don't have acees to a real bootfitter so i have to solve the problem alone.
The forward lean is my main problem. I am trying to decrease it. I already removed the rear spoilers of my boots. I know that a lifter under the toe of the boot is probably the best way to go but i have only one pair of skis, so it's not a problem.
But what about my idea, to raise the toe of the binding even more (currently it has 1mm delta) and get to 2-3mm of negative delta. Wouldn't this help decrease the forward lean??? I hope it would. But i don't know for sure.
For me it would be much easier to raise the toe of the binding than to raise the toe of the boot. I would have to find some screws that would be long enough and what about the piece of plastic that i should be using?
For these reasons i am trying to get away with a much simpler solution - raise the toe of the binding so that it will be higher than the heel. Btw, this should also decrease the ramp angle, but i can grind the bootboard myself.

One more question. This is for those who are/were in a similar situation. Anybody built a home-made lifter for the toe of the boot? How long should the screws be? How many should be used? What plastic did you use? How thick? etc. But this is plan B because i hope the first solution will work.

Thanks again.
post #8 of 29
alu,

As with checkracer, this answer is a 301/401 answer...

Raising the toepiece has the same impact as a "gas pedal" (a lifter under the toe). That result is as follows:

1) It decreases the bootboard ramp angle.
2) It decreases the angle of the tibia to the ski.
3) It does not change the angle of the ankle (a component of forward lean).

If you want to just do 1, you can do it inside the boot through modifications to the bootboard. Not simple or for the faint-of-heart.

If you want to do 2 while also straightening the ankle flex (counter of 3), you can change the forward lean of the boot. This requires boot work, as well.

The following is post-graduate level!

Those two things said, the impact of raising the toe will do more than simply change 1 and 2. It will also change your balance. This, in my opinion, is the biggest issue. While there are some on EpicSki who claim that the ability of the human body to compensate for balance challenges means that the balance we have statically on skis is immaterial, I disagree strongly. I think that our static balance on skis is the most important characteristic of our equipment.

So, if you lift the toe, you maintain the ankle angle while flattening the boot board ramp. The flattening of the ramp will place your CoM (Center of Mass) in a particular plane, with it's gravitational force component pointed down at a location in your foot farther back than was the case before. If this location moves past the center of your arch (it should be a bit ahead of that point), your balance will be compromised rearward and require body joint compensations that will make it difficult to ski "stacked".

It is this area of balancing that I would ask you to make sure that you are taking into account. If the effective boot board ramp angle is less than 2.5 degrees, it's probably too flat. 3 degrees is typical. If you are tall relative to your feet size, you'll need flatter. If you are short relative to the size of your feet, you'll need steeper. There are ways to calculate this, as well.
post #9 of 29
Quote:
Originally Posted by alu
One more question. This is for those who are/were in a similar situation. Anybody built a home-made lifter for the toe of the boot? How long should the screws be? How many should be used? What plastic did you use? How thick? etc. But this is plan B because i hope the first solution will work. Thanks again.
"Using an appropriate interface you can combine virtually any plate and any binding. The simplest "interface" would be 8 mm (home-made) lifters (8 mm because of the screw length, could be even shortened to maybe 5-6 mm) screwed onto the original plate and used as the actual plate to accomodate the binding..."
(from my post Nr. 4 of Aug 4)
http://forums.epicski.com/showthread.php?t=28407

If you can use screws long enough use them. Officially they should be 8 mm immersed but it also depends on the material they would stick in. Metal needs less, if the original thread is good with little risk to strip it you might, IMO, go with 6 mm, especially if the add-on lifter is not too thick and the screw not extremely long (say not more than 15 mm, the longest I know suitable for most toes are 24 mm). If the screws go through the lifter you may use any sort of tougher plastics. If you have to use the method I desribed in the quotation you need some higher-density PU or nylon or something of the sort for the screws to hold well. You see it when you try to drill a hole how hard or soft the material is. Sound judgement tells you if it´s hard enough to hold the screw well.
VIST has some special lifters 2/3/4 mm (RI32/RI33/RI34) but it´s no use to pay the money, they are just a bit more elegant pieces of nylon.
If mounting the DIY lifter I use 4 screws with a fairly broad pattern.
post #10 of 29
Thread Starter 
Thanks guys for your replies.

ssh, from what you said it seems to me the forward lean will not decrease. Did i understand correctly?

I am interested in the forward lean because the ramp is not such a big problem. I can grind the bootboard myself, i am not afraid of doing it. But it seems there is nothing i can do to decrease the forward lean which is killing me! I have the Tecnica Diablo Race 130. I admit i bought it without gathering too much info about it. I even don't know how many degrees of forward lean this boot has (without the rear spoiler).

ssh, from what you said it seems the angle of the ankle will remain unchanged if i put a lifter under the toe of the binding.

It's dissapointing but at least i know i should not even bother to try it. After i removed the rear spoiler of my Diablos, i felt better but still it has a lot of forward lean. I could grind the bootboard but this will probably lock the ankle a bit more.

I hope someone can help because i don't want to start looking for a new boot! The Diablo is new.
post #11 of 29
alu, you have it correct.

Question for you: what is it about the forward lean that is causing you a problem?

Also, a few specifics, please:

- how tall are you?
- what size are the boots?
post #12 of 29
Thread Starter 
5 foot 9
size 25.5 MP

The problem is that my knees are over the front of the boot, not too much, slightly over the toebox area. If i should draw a line between the knee and the boot, the knee is just in front of the boot, but only just. From what i know, it should not pass the front of the boot.

One more thing. This may be important. I have flexible ankles. I can flex the ankle a lot before the heel lifts off the ground!
post #13 of 29
Thread Starter 
Check out this link:http://www.gmolfoot.com/balance.html Look at the three pics which present the stance.My stance is somewhere between the forward position and the balanced position. I am not so far forward like the guy in the FORWARD position but i don't have the balanced stance of the same guy in the last picture.
post #14 of 29
The Diablos have a lot of ramp (and forward lean), so I'm not too surprised. Interesting sidenote: I'm 6' and wear the same boot size in the Tecnica XT... You don't have to go as flat as I do. I think that putting some lift under the tow would likely help you. You might try it while standing in your boots on the flat... Put 1mm lifters under your boots until you get "balanced" as in those pictures. Then, you'll know how much lift you need under your toes...

Since your ankle flex isn't an issue, it's likely that the forward lean isn't going to be an issue.
post #15 of 29
Chris I did mistate the opening of the ankle. I should always reread what I type. Reducing the ramp will close the ankle until you reduce forward lean. Chris from my understanding this all has to do with the state of the flex/stretch of certain muscles in the calf and their effect on our balance. anyway, changing the ramp angle inside the boot doesn't change the angle between the boot cuff or leg shaft and the bottom of the boot, nor does changing the delta angle change the amount of forard lean in the boot. These are complicated issues. Later, RicB.
post #16 of 29
Quote:
Originally Posted by RicB
These are complicated issues. Later, RicB.
I´ll try the following formulation:
It´s probably not so difficult to imagine and understand the principles of the planes and angles. IMO complicated is the knowledge of the changes a specific skier needs, and of their consequences. The changes are often interrelated. e.g. less ramp inside the boot - less forward lean - changes of delta.
Agreed?
post #17 of 29
Quote:
Originally Posted by RicB
...These are complicated issues. Later, RicB.
No doubt. And, a little change goes a long way!

Thanks for the follow up

Chris
post #18 of 29
just throwing out a few ideas....

What about grinding the back of the cuff where it meets the heel?

That would create less forward lean would it not? But would that not also move the front of the cuff away from the lower shell, reducing snowfeel?

Another way would be to mold the top of the cuff (using heat) so that the rear of the cuff is further back from the calf. This is identical to removing the spoiler, but moves the contact point of calf to cuff further back, and you should be able to stand more upright. It should not affect the front cuff to lower shell interface....

But, neither option will change the amount the knees will move over the toe.

Perhaps the molded cuff together with more padding on the tongue will physically change the forward lean?
post #19 of 29
Thread Starter 
Thanks for the replies.

One more thing i would like to add. This is a result of ssh's idea. Yes, i want to put a lifter under the toe but can't this be the toe of the BINDING?

ssh, you mention the heel of the boot, but as i said before, i don't have access to a REAL bootfitter, so i would have to do it myself. I think it's a little complicated.
So i want to put a lifter (in fact add another lifter to the existing lifter) under the toe of the BINDING.. Do you guys think it will have the same effect as the lifter under the boot? That's what i am trying to find out. I already have a non home-made lifter which i can put under the toe of the boot. It is a 2mm lifter. The lifter which is already under the toe of the binding also has 2mm. So it means the toe of the binding will be raised 4mm. What do you think guys? The only possible problem would be how the toe of the boot will stay in the toe of the binding. Am i right?
post #20 of 29
Quote:
Originally Posted by alu
Thanks for the replies.

One more thing i would like to add. This is a result of ssh's idea. Yes, i want to put a lifter under the toe but can't this be the toe of the BINDING?
Yes "it can" be done under the binding. I have done this with my Look Pivot bindings ...I don't know how it would affect your Marker's though.
post #21 of 29
Quote:
Originally Posted by alu
One more thing i would like to add. This is a result of ssh's idea. Yes, i want to put a lifter under the toe but can't this be the toe of the BINDING?

ssh, you mention the heel of the boot, but as i said before, i don't have access to a REAL bootfitter, so i would have to do it myself. I think it's a little complicated.
So i want to put a lifter (in fact add another lifter to the existing lifter) under the toe of the BINDING.. Do you guys think it will have the same effect as the lifter under the boot? That's what i am trying to find out. I already have a non home-made lifter which i can put under the toe of the boot. It is a 2mm lifter. The lifter which is already under the toe of the binding also has 2mm. So it means the toe of the binding will be raised 4mm. What do you think guys? The only possible problem would be how the toe of the boot will stay in the toe of the binding. Am i right?
No problem doing this as long as your Markers have separate toe/heel pieces. 4mm isn't too much delta, and your boot should rest on the AFD, still. You might want to check it, though, before you screw the bindings back in.

I had a 2mm lifter under the toepiece of my Markers 03/04 in addition to the 3mm gas pedal on my boot toe.
post #22 of 29
Thread Starter 
cgeib and ssh,

Thanks a lot for this great news! This is the answer i was looking for.

It is much easier to add or remove a lifter under the toe of the binding than to add a lifter under a toe if you are not a bootfitter. There are only three screws which hold the toe.
One more thing: i have the Marker WC SL plate which has the toe slightly higher than the heel, so this should help me. The binding is the Marker Comp 14.0 eps. I added a 2mm lifter and after my measurements i only have 1mm delta.

I can test the new setup at home to see how it affects my balance. I should have a more balanced stance. The new delta will be negative but i hope it will do the job.
I will tell you how i feel after i add the lifter.
post #23 of 29
Just be aware that each time you screw the bindings in, the hold gets more tenuous.
post #24 of 29
Quote:
Originally Posted by checkracer
I´ll try the following formulation:
It´s probably not so difficult to imagine and understand the principles of the planes and angles. IMO complicated is the knowledge of the changes a specific skier needs, and of their consequences. The changes are often interrelated. e.g. less ramp inside the boot - less forward lean - changes of delta.
Agreed?
Agree. My own experience showed me, and what I see everyone around my locker room working towards is being more upright and reducing the ramp angle in their boots. I pretty much always skied atomic bindings recently, so the delta angle is not improtant to me. It does get in the way if you ski a binding that has alot of delta. For me it seems safe to say that most will benefit by reducing the ramp angle and bringing forward lean closer to 12-14 degrees. I don't know anyone who has ended up going the opposite direction. Not saying that they aren't out there, but I haven't exsposed to any. Later, Ricb.
post #25 of 29
Quote:
Originally Posted by BigE
just throwing out a few ideas....

What about grinding the back of the cuff where it meets the heel?

That would create less forward lean would it not? But would that not also move the front of the cuff away from the lower shell, reducing snowfeel?

Another way would be to mold the top of the cuff (using heat) so that the rear of the cuff is further back from the calf. This is identical to removing the spoiler, but moves the contact point of calf to cuff further back, and you should be able to stand more upright. It should not affect the front cuff to lower shell interface....

But, neither option will change the amount the knees will move over the toe.

Perhaps the molded cuff together with more padding on the tongue will physically change the forward lean?

Those are all good suggestions. My last two pairs of boots I ground away gently and slowly where the cuff meets the stop in back. Worked well. I have also heard of the using the intuition liner (I think) with the double overlap in front of the shin as a way of getting a more upright stance in a boot. Later, RicB.
post #26 of 29
I'm not going to read all this so I may miss some points or rehit others. If you want to reduce forward lean the toe lift will help if you want to open the ankle you need to work on the boot. I wouldn't add toe lift to achieve negative ramp angle but then I've never tried it. At this point I think you're better working on the boot.

Depending on what is pushing you forward simply flaring the top of the boot spoiler back and/or cutting lower can do a lot if your calf muscle is low and/or large.

Big E's idea of grinding at the top of the heel can work well if the problem is a somewhat thick achilles tendon. I would focus more on widening the groove for the achilles then actually grinding it back further. That is to say grind out the sides of this groove not the middle.

(Rereading Big E's post I realize we are talking different things.) While BigE's idea can do what he states and may be (or be part of a) solution I find it more difficult then you might think and would suggest exploring the options I mention first. At least to see if your situation lends itself to these solutions. Regardless I believe in a flat or close to flat binding and from there addressing boot problems at the boot as opposed to bandaids elsewhere.

For flaring the spoiler a heat gun and football maybe some strapping is all you need. Pretty easy but you have to be careful.
post #27 of 29
Alu,
Jim Lindsay added 5mm toe lifts to my Technica Alu's last fall.
As I remember cost was $160 includeding shipping back from Colorado.
I see doing this modification yourself as risky because you need to remove the corresponding amount of material from the top of the toe to maintain proper binding function.
For me the effect was to allow a taller stance and people stopped telling me I was always in the back seat.
The 5mm was determined by a "D" team guy and result confirmed by a different "D" teamer.
Contact Jim @ bootinfo@boottech.net
I've been told that Jim is the boot guy for most of the Demo team. He has quite a following. After hearing his presentation at 2004 NationalAcademy, I believe he knows his stuff.
Good luck
Kazooski
post #28 of 29
Thread Starter 
I know the best thing to do would be to reduce the delta to zero and than work on the boot.
I currently have 1mm delta. The heel is 5mm higher than the toe. The plate is 2mm lower in the heel and that brings the delta to 3mm. I added a 2mm lifter and voila 1mm! If i add one more lifter (2mm) i will have a negative delta, but for only 1mm. Is this such a big deal? It isn't 3-4mm as i thought it would be.

I will see how how much it will affect my stance. IF this does not work, i will probably work on the boot.

BigE, i did grind the back of the cuff where it meets the heel but to my surprise it didn't work. The cuff was in the same position as before. The cuff does not move back to make contact with the heel. And i did grind a few mm's.
post #29 of 29
Thread Starter 
I added another lifter today. It felt better.
I have now 1mm of negative delta.

Thanks for all the replies!
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Ski Gear Discussion