Does a Short BSL Affect Turn Initiation?

[Josh Matta]

View attachment 85361 Does a Short BSL Affect Turn Initiation?

Well, moving the heel of a size 6 foot 3 inches to the right while pivoting on the middle or toe turns the foot or ski more degrees than pivoting a size 12 foot heel the same 3 inches. So it would seen that yes, there is a relationship between the pivot force rotation degrees and BSL. It's also why the DIN is different for different BSLs. How that translates to carving a modern ski would differ of course, but I would still guess that different distance between leg/heel and toe or mid arch dies affect initiation dynamics some.

Left is short BSL pivoted hell laterally right and right is long BSL pivoted heel right the same distance, left is more degrees of a turn for the same effort.

you shouldnt be pivoting from the toes you should be turning from boot center. This also assuming you are initiating turns by pivoting first which most good skiers are not doing most of the time but only using pivot entry tactically

SHORT BSL does not affect turn initiation! but short BSL is more easily thrown out of for and aft alignment which can affect turn initiation.

 

[Lauren]

I have built 1mm, 2mm, and 3mm shims and ski with them in my pocket. I think these will really come in handy when demoing "foreign" skis with unknown deltas.

Would you mind giving a short crash course on how you “install” them on the fly? Just slip them between your boot sole and the AFD plate? Or do you need to adjust the AFD height?

 

[Josh Matta]

yeah they go between the boot sole and AFD either on the toe or heel depending on what delta is good for you.

 

[Lauren]

yeah they go between the boot sole and AFD either on the toe or heel depending on what delta is good for you.

Does that not mess up the tiny “gap” that is required for the AFD to move when it releases?

 

[crgildart]

you shouldnt be pivoting from the toes you should be turning from boot center. This also assuming you are initiating turns by pivoting first which most good skiers are not doing most of the time but only using pivot entry tactically

SHORT BSL does not affect turn initiation! but short BSL is more easily thrown out of for and aft alignment which can affect turn initiation.

It doesn't matter where the pivot point is... and mid arch in my quote referred to mid sole. a 6 inch stick twisted 3" at the base turns more degrees than a 12" stick also twisted 3" at the base. That is simple physics and geometry. Moving ti mid sole actually amplifies the difference in degrees FWIW..

 

[Noodler]

Does that not mess up the tiny “gap” that is required for the AFD to move when it releases?

Using these shims for testing fore/aft alignment absolutely decreases your safety. The shims will interfere with the operation of the binding and, as such, are only to be used for short testing periods done in areas of the mountain where you feel safe and can handle the conditions and slope.

Note that some binding toes will not handle up to a 3mm shim, so you may be limited in what you can test based on your binding. When the shims are permanently installed on the boot, the boot toe lug is routered back into ISO 5355 compliance (19mm +/- 1mm height).

 

[Noodler]

you shouldnt be pivoting from the toes you should be turning from boot center. This also assuming you are initiating turns by pivoting first which most good skiers are not doing most of the time but only using pivot entry tactically

SHORT BSL does not affect turn initiation! but short BSL is more easily thrown out of for and aft alignment which can affect turn initiation.

Years ago I would have argued so hard against this statement. We all evolve in our understanding of the sport and how skis work on the snow. I have learned through the work of others and my own experimentation that skiing from the center of the boot should be the goal. Tom Gellie has a number of very educational and influential videos available that I've been watching lately. He touches on the topic of where you should focus inside of the boot in your ski turns in order to best "operate" the ski.

 

[Josh Matta]

I would also argue that external rotary force from the skis sidecut should be allowed to turn your boot from center.

 

[crgildart]

I would also argue that external rotary force from the skis sidecut should be allowed to turn your boot from center.

This is also true. The leg bone's connected to the ankle bone, ankle bone's connected to the foot bone. and length of foot matters for ankle leverage used to turn that foot... However that's all connected to the ski with zero play/slop so your foot is now essentially your ski. Latteral side to side movement and downward pressure is way more relevant than any twisting and turning when riding a sidecut.

 

[Lauren]

Using these shims for testing fore/aft alignment absolutely decreases your safety. The shims will interfere with the operation of the binding and, as such, are only to be used for short testing periods done in areas of the mountain where you feel safe and can handle the conditions and slope.

Note that some binding toes will not handle up to a 3mm shim, so you may be limited in what you can test based on your binding. When the shims are permanently installed on the boot, the boot toe lug is routered back into ISO 5355 compliance (19mm +/- 1mm height).

Gotcha. That confirms what I was thinking. I wasn't sure if you were doing something differently that I hadn't thought of.

 

[Swiss Toni]

At 5'6" with a size 23.5 boot I have struggled with turn initiation due to high binding deltas. In 2008 Head increased the delta of their Freeflex Plus bindings from 3.5mm to 7mm, turn initiation with the new Head Supershapes that I bought to replace some with the 3.5mm delta bindings was much harder, so I swapped the bindings.

In order to check that this was the optimum delta I did some tests using the procedure outlined by Noodler, except that I made some 0.5mm shims in addition to the 1mm, 2mm and 3mm shims he made. I don’t think the type of plastic is important as long as it is harder than Shore 50D (ISO 5355 requires that ski boot soles are at least Shore 50D). Assuming the thickness of the front part of your boot soles is 19mm release will likely be affected if you use shims thicker than 1mm.

I was very surprised at how small the range was, outside the range of 2.5mm to 3.5mm turn initiation was a lot harder. Later that season I bought a heavily discounted pair of Palmer PO2 rockered carving skis, they worked best when I reduced the binding delta to 0.5mm. As gas pedalling the boots would have screwed up my fore/aft alignment on the Supershapes I shimmed the binding toe pieces on the PO2s.

It’s a good idea to measure the thickness of the bits of plastic you use and the thickness of any lifters you buy as the stated thickness of some of the lifters supplied by the ski boot/binding manufactures is not always the same as the measured thickness.

 

[Noodler]

At 5'6" with a size 23.5 boot I have struggled with turn initiation due to high binding deltas. In 2008 Head increased the delta of their Freeflex Plus bindings from 3.5mm to 7mm, turn initiation with the new Head Supershapes that I bought to replace some with the 3.5mm delta bindings was much harder, so I swapped the bindings.

In order to check that this was the optimum delta I did some tests using the procedure outlined by Noodler, except that I made some 0.5mm shims in addition to the 1mm, 2mm and 3mm shims he made. I don’t think the type of plastic is important as long as it is harder than Shore 50D (ISO 5355 requires that ski boot soles are at least Shore 50D). Assuming the thickness of the front part of your boot soles is 19mm release will likely be affected if you use shims thicker than 1mm.

I was very surprised at how small the range was, outside the range of 2.5mm to 3.5mm turn initiation was a lot harder. Later that season I bought a heavily discounted pair of Palmer PO2 rockered carving skis, they worked best when I reduced the binding delta to 0.5mm. As gas pedalling the boots would have screwed up my fore/aft alignment on the Supershapes I shimmed the binding toe pieces on the PO2s.

It’s a good idea to measure the thickness of the bits of plastic you use and the thickness of any lifters you buy as the stated thickness of some of the lifters supplied by the ski boot/binding manufactures is not always the same as the measured thickness.

Good post. A couple comments... First, I have to agree regarding the small range of adjustments that can have such dramatic impact. 1mm seems so small, but in the world of boot fitting and also stance alignment, that 1mm change is quite impactful.

What I haven't totally wrapped my head around yet, is the interaction between the forward lean and the net ramp after delta changes. I get how the bootboard ramp and forward lean should be adjusted correctly for your dorsiflexion RoM, but I'm not sure yet whether these delta changes are getting the job done by reducing the effective forward lean or the net ramp (or both).

I guess I would need to come up with a method to test forward lean changes separate from the ramp changes to figure out which provides the most impact for the fore/aft alignment. Bootboard ramp angle changes are the most difficult since they normally require modifications that involve sanding down or building up the bootboard. Forward lean can be easier to adjust in some boots than others. I don't feel like cuff spoilers or trail maps shoved into the boot cuff are all that effective for actually changing the true forward lean of the boot.

Finally, a digital caliper is your friend for measuring shim thickness and binding delta. An inclinometer or digital angle gauge is also handy for measuring the resultant angles.

 

[AmyPJ]

I might grab a digital angle gauge. I know my phone can do it with an app, but I don't think that is very reliable when measuring a non-flat surface. Super curious to compare how my last three pair of boots compare to my new pair that I will FINALLY get to ski in this week. Truthfully, two pair ago, I was in a Salomon XMax and was really progressing in them--the stance felt really natural, I was able to use the stock liner, and they had a tall cuff. But, they were too wide and had too much volume overall (and were too soft.) I spent a season in a pair of Head B5 with WAY too much forward lean and ramp, and my confidence took a big hit. Spent two seasons on a Tecnica Mach 1 95 LV and the ramp felt good, but the cuff was too low and they had too much volume in the instep. Had to use a Boot Doc liner as the stock liner did not fit at all. I recently discovered that the BD liner had a thicker sole and was pushing me up, so probably not giving me optimal connection with the boot. It's my understanding that the newer BD liners have remedied this.

Just bought a pair of Nordica Promachine 105 and it feels like the best of all the boots combined. Taller cuff, more upright stance, instep is locked in with the stock liner golfclap

All the boots are a 22.5 except the Head, which is a 23.5. Yes, I have the added bonus of having stupidly low-volume feet so my choices are quite limited. It's pretty awesome the the Promachine series come in flexes as low as 85. I wish they had been around for me 5 years ago!

I"m glad I brought this thread back up again, and appreciate the additional feedback!

 

[Swiss Toni]

Before changing the binding delta, I tried adjusting almost everything else. As the forward lean angle is the same no matter what the boot size is, I set it as upright as possible. I couldn’t grind the boot board because of volume issues so I changed the boot board ramp angle by adding a wedge to the front half of the boot board (PVC foam board and double-sided carpet tape are your friends). I also added shims made from wet molded 3mm thick vegetable tanned leather to the back of the inner boot and to the tongue to take up the extra space in the shaft of the boot due to my skinny calves the tongue shims were needed to prevent me overtightening the top buckle which changes the angle of the cuff. Apart from changing the boot board angle, which didn’t have any noticeable effect the changes improved my balance, but did not improve turn initiation. I think these changes are akin to adjusting the seat and steering wheel in a car in order to optimize the driving position.

I think changing the binding delta is akin to making changes to a car’s suspension to improve cornering etc. so I don’t think it matters what the “interaction between the forward lean and the net ramp” is. I didn’t measure any of the angles either before or after so I don’t thing an angle gauge is necessary, but a digital caliper or thickness gauge is essential to ensure that the thickness of the plates you use to lift the bindings or boots are the same as the shims you used in testing.

 

[Noodler]

Before changing the binding delta, I tried adjusting almost everything else. As the forward lean angle is the same no matter what the boot size is, I set it as upright as possible. I couldn’t grind the boot board because of volume issues so I changed the boot board ramp angle by adding a wedge to the front half of the boot board (PVC foam board and double-sided carpet tape are your friends). I also added shims made from wet molded 3mm thick vegetable tanned leather to the back of the inner boot and to the tongue to take up the extra space in the shaft of the boot due to my skinny calves the tongue shims were needed to prevent me overtightening the top buckle which changes the angle of the cuff. Apart from changing the boot board angle, which didn’t have any noticeable effect the changes improved my balance, but did not improve turn initiation. I think these changes are akin to adjusting the seat and steering wheel in a car in order to optimize the driving position.

I think changing the binding delta is akin to making changes to a car’s suspension to improve cornering etc. so I don’t think it matters what the “interaction between the forward lean and the net ramp” is. I didn’t measure any of the angles either before or after so I don’t thing an angle gauge is necessary, but a digital caliper or thickness gauge is essential to ensure that the thickness of the plates you use to lift the bindings or boots are the same as the shims you used in testing.

You bring up some good points. I like your analogy comparing to the seat and steering wheel adjustments. Modifying the bootboard has direct implications for the boot fit, so you are limited in what you can do there. Many boots also make forward lean adjustments quite difficult (pretty much impossible on a Head Raptor). So the gas pedal mod actually ends up being the "easy way" to modify the fore/aft alignment.

And I was thinking about something while I was skiing today. There's lots of discussion about how to "get forward" on your skis. There's lots of drills and other skiing technique instruction on getting forward. So you have to ask why? It's not because we need to be forward for the sake of being forward. The goal I believe is to get sufficient tip engagement. Well if you can get great tip engagement and have full access to the entire ski edge length, then who cares where your upper body is relative to the skis. We just assume that your upper body (especially your hips) has to be forward, but that's only the case if your unable to operate the skis correctly. Once you're aligned properly, the correct upper body and hip position happens naturally (at least for me).

I mention all this because once you have your fore/aft alignment correct (via a gas pedal on your boots or however), then it seems almost too easy to get the tip and edge engagement you need. I can't tell you how many drills I did over the years and how much I fought to try to be forward on my skis. All I really needed was someone to slap me upside the head and say what you really need is to get your fore/aft alignment corrected. A lot of really good skiers and instructors helped me along the way over the past 10 years, but no one gave me the head slap I really needed (although HH did mention it to me during a camp day many years ago).

 

[AmyPJ]

I need to check in after a few days in the new boots. What a difference they've made! My fore/aft must be better dialed on them, or the taller cuff helps me in that regard. I'm not sure. All I know is I can stand MUCH taller and my stupid stem is disappearing quickly. I feel connected to the entire ski vs. just from the boot back. For once, I actually feel like I can do drills without becoming extremely frustrated.

So @Noodler, my current experience seems to agree with yours and the fore/aft and hips being balanced properly. I now have a LOT of work to do to erase old habits, but I'm excited about it instead of feeling defeated about it.

 

[Noodler]

I need to check in after a few days in the new boots. What a difference they've made! My fore/aft must be better dialed on them, or the taller cuff helps me in that regard. I'm not sure. All I know is I can stand MUCH taller and my stupid stem is disappearing quickly. I feel connected to the entire ski vs. just from the boot back. For once, I actually feel like I can do drills without becoming extremely frustrated.

So @Noodler, my current experience seems to agree with yours and the fore/aft and hips being balanced properly. I now have a LOT of work to do to erase old habits, but I'm excited about it instead of feeling defeated about it.

It brings my heart joy to hear about your positive experience...

But really there's still a lot of frustration I have with the industry when it comes to this all too critical alignment aspect. On one hand, there's the instruction side and the diagnosing of fore/aft alignment issues. On the other, there's the manufacturers who insist on "playing games" with binding delta year after year.

I'll say it again, all manufacturers should adopt a 0 delta mandate and allow all fore/aft alignment to be done at the boots. If manufacturers all used different lateral alignment in their bindings people would be screaming from the rooftops. Imagine Salomon decides that all their bindings should be 1* out while Look thinks 0.5* in is better. It would create insanity and doesn't make any sense. Yet we accept that manufacturers wildly vary in their fore/aft deltas. And it makes even less sense when you factor in the different boot BSL values which results in completely different fore/aft angles. It just doesn't make any sense. 0 delta is the only way to solve this. I believe that having large amounts of binding delta (high heel, low toe) and boot forward lean are holdovers from the straight ski days.

I also believe that if you're going to err one way or another, you're actually better off erring toward having your toes too high rather than too low. Too much high heel/low toe delta is probably responsible for the vast majority of the skiing public being forever stuck in the back seat.

 

[AmyPJ]

It brings my heart joy to hear about your positive experience...

But really there's still a lot of frustration I have with the industry when it comes to this all too critical alignment aspect. On one hand, there's the instruction side and the diagnosing of fore/aft alignment issues. On the other, there's the manufacturers who insist on "playing games" with binding delta year after year.

I'll say it again, all manufacturers should adopt a 0 delta mandate and allow all fore/aft alignment to be done at the boots. If manufacturers all used different lateral alignment in their bindings people would be screaming from the rooftops. Imagine Salomon decides that all their bindings should be 1* out while Look thinks 0.5* in is better. It would create insanity and doesn't make any sense. Yet we accept that manufacturers wildly vary in their fore/aft deltas. And it makes even less sense when you factor in the different boot BSL values which results in completely different fore/aft angles. It just doesn't make any sense. 0 delta is the only way to solve this. I believe that having large amounts of binding delta (high heel, low toe) and boot forward lean are holdovers from the straight ski days.

I also believe that if you're going to err one way or another, you're actually better off erring toward having your toes too high rather than too low. Too much high heel/low toe delta is probably responsible for the vast majority of the skiing public being forever stuck in the back seat.

I would be very happy if all bindings were at zero. OR at the very least they were all the same.

 

[Noodler]

Cross-posting this link here because I think my "treatise" on binding performance provides some food for thought for @AmyPJ too...