Study: Evaluating wrapping alpine ski boots during on-snow carving

[Philpug]

Interesting study with the whole experiment funded by BOA. With that caveat, BOA funded it to prove that their technology is not superficial but does make a difference.

Evaluating wrapping alpine ski boots during on-snow carving

IntroductionAlpine ski boots enable rapid and precise force transfer between skier and ski while carving. These boots are made of rigid plastic and fit tightly commonly through four buckles. Such a fit can improve speed and control but also pain and discomfort. In athletic footwear, alterations...

www.frontiersin.org

 

[Bill Miles]

Used to wrap old leather boots with long thongs. Don't know if it really helped, though.

 

[coops]

“In both locations, two ski boots (Salomon S/Pro Supra Max 120 Flex) that were identical aside from the shell (lower) boot closure system were tested: BOA and Buckle”


“Salomon S/Pro Supra Max. The Buckle configuration was originally produced with a BOA dial and was retrofitted with Buckles. “ - why would a Boa employed researcher retrofit buckles to a clog that is not designed for buckles… rather than use the previous years same model with 4 buckles (that was designed for buckles)?

 

[onenerdykid]

“In both locations, two ski boots (Salomon S/Pro Supra Max 120 Flex) that were identical aside from the shell (lower) boot closure system were tested: BOA and Buckle”


“Salomon S/Pro Supra Max. The Buckle configuration was originally produced with a BOA dial and was retrofitted with Buckles. “ - why would a Boa employed researcher retrofit buckles to a clog that is not designed for buckles… rather than use the previous years same model with 4 buckles (that was designed for buckles)?

The old boot has a VERY different last shape, so if you are trying to feel the difference in the same boot but compare closure systems, comparing old S/Pro to S/Pro Supra you will never notice the difference simply between BOA and buckles. You need the same boot with the only difference being the closure system.

The better example to use would be to take a Hawx Ultra XTD 130 BOA and Hawx Ultra XTD 130 buckle. We made both and would have been a better side-by-side comparison. Those that have done it (like Blister) have reported on the fit differences.

 

[cem]

S Pro supra is a completely new shape, its not an S Pro and its certainly not an S max or X max


we know that boa wraps better but they have just discredited their own research

 

[RoninSkier]

Interesting study with the whole experiment funded by BOA. With that caveat, BOA funded it to prove that their technology is not superficial but does make a difference.

Evaluating wrapping alpine ski boots during on-snow carving

IntroductionAlpine ski boots enable rapid and precise force transfer between skier and ski while carving. These boots are made of rigid plastic and fit tightly commonly through four buckles. Such a fit can improve speed and control but also pain and discomfort. In athletic footwear, alterations...

www.frontiersin.org

Interesting but closure mechanisms are secondary to other shell features and performance comfort primarily comes from the liner IMHO.
I submit boot designers / manufacturers need to focus on those and by priority.

 

[Dave Marshak]

My instep is so high that I need to use a long buckle over it. The toe buckle always needs to be tight enough to keep water out, but if I tighten the instep as much as the toe I always have foot pain. The boa seems like it would cause equal pressure at both points, so it's not for me. I hope it never becomes standard. YMMV

dm

 

[pchewn]

My instep is so high that I need to use a long buckle over it. The toe buckle always needs to be tight enough to keep water out, but if I tighten the instep as much as the toe I always have foot pain. The boa seems like it would cause equal pressure at both points, so it's not for me. I hope it never becomes standard. YMMV

dm

Yes, this is exactly the point I tried to make earlier: BOA has 50% less control over boot closure than buckles. (1 adjustment for BOA, 2 for buckles).

See here: https://www.skitalk.com/threads/boa-its-not-just-a-closure-system.31872/post-906390

This study also showed that the average skier tightened the closure more using buckles than with BOA. I speculated why this may be true. Then @onenerdykid told me it should be the opposite: because BOA has a more powerful 4:1 gear ration for closure. I measured my buckles at 4.3 : 1 gear ratio .... thereby showing that BOA is a less powerful closure system.

See here: https://www.skitalk.com/threads/boa-its-not-just-a-closure-system.31872/post-906206

See here: https://www.skitalk.com/threads/boa-its-not-just-a-closure-system.31872/post-906387


BOA's own study shows that buckles are a more powerful closure system than BOA.
Measuring the gear ratio (lever advantage) of BOA [4:1] vs buckles [4.3 : 1] shows buckles more powerful.
BOA is definitely 1-control (the knob) vs 2-control [each buckle] .

Yet the proponents of BOA always come back to: "BOA is more uniform, less pressure points, easier to close" "Have you ACTUALLY tried a BOA?"

I supposed I actually have to buy a BOA boot to compare it's price against a buckle boot?
Maybe I actually have to experience a parachute failing in order to know it's worse than a parachute working?

 

[Dave Marshak]

Boa is like Gripwalk: the answer to a question no one asked.

dm

 

[onenerdykid]

My instep is so high that I need to use a long buckle over it. The toe buckle always needs to be tight enough to keep water out, but if I tighten the instep as much as the toe I always have foot pain. The boa seems like it would cause equal pressure at both points, so it's not for me. I hope it never becomes standard. YMMV

dm

Maybe try it before you rule it out? Too many high-instep people are saying the opposite. Both can't be true.

Buckles push downward. BOA system wraps more uniformly, and I don't mean between position 1 and position 2 buckles. Wrapping more uniformly means as it closes it is not collapsing the way buckles do.

 

[onenerdykid]

BOA's own study shows that buckles are a more powerful closure system than BOA.
Measuring the gear ratio (lever advantage) of BOA [4:1] vs buckles [4.3 : 1] shows buckles more powerful.
BOA is definitely 1-control (the knob) vs 2-control [each buckle] .

Yet the proponents of BOA always come back to: "BOA is more uniform, less pressure points, easier to close" "Have you ACTUALLY tried a BOA?"

I supposed I actually have to buy a BOA boot to compare it's price against a buckle boot?
Maybe I actually have to experience a parachute failing in order to know it's worse than a parachute working?

Buckles collapse the shell. BOA wraps the shell with less pressure points. This is just true and you'll experience it when you actually try it for yourself.

Your parachute analogy falls short. Get it? It falls short because experience is a necessary requirement for us to know things. You cannot know all things apriori (without experience), as in only using tautologies and definitions. You need to apply your apriori concepts with your own experiences to get knowledge. That means go test your ideas.

Right now you are just living in world of ideas without verifying if your hypothesis tests out.

I encourage you to test it out and see if your ideas hold true. I know I have.

 

[Dave Marshak]

Buckles push downward. BOA system wraps more uniformly, and I don't mean between position 1 and position 2 buckles. Wrapping more uniformly means as it closes it is not collapsing the way buckles do.

That sounds like marketing. I looked at a boa boot yesterday and it looks like the boa is attached at the same points a buckle would be.
I won't try them. I bought new boots last year and their gonna last until I'm old enough for a Nordica HF.

dm

 

[pchewn]

Your parachute analogy falls short. Get it? It falls short because experience is a necessary requirement for us to know things. You cannot know all things apriori (without experience), as in only using tautologies and definitions.

Very well done! "Falls short"

But seriously, I definitely do NOT have to experience things before knowing things. The parachute analogy is a perfect example. Why EXPERIENCE a parachute failure to KNOW it is a bad thing?

Why pay for the ski boots (experience) to know the impact on your bank account. Why not just KNOW that the bank account will be depleted by $699 if you buy them?

 

[cantunamunch]

Buckles push downward. BOA system wraps more uniformly, and I don't mean between position 1 and position 2 buckles. Wrapping more uniformly means as it closes it is not collapsing the way buckles do.

Leaving the dyed-in-the-wool arguments aside,

The rest of us get that.
The rest of us get that buckling creates /\/\/\ deformations in the shell wall.
The rest of us get that the deformations created by BOA for the same force across the flap could be smaller.

But the disappearance of independent adjustment (or non-appearance of independently adjustable pulley points) makes us think that BOA is a solution for mouldable shell and thin-wall shell boots only. Will BOA-optimisation consist largely of thinning the wrap?

If BOA is studied and shown clearly advantageous in boots with chonky racer-grade polyurethane most of my objections will go away.

 

[AlexisLD]

I think one argument that @onenerdykid was making is that BOA closes the boot without squeezing, is that correct? This is a bit counterintuitive to me as when I want a good fit I squeeze as hard as I can on my gear: boot, helmet, backpack, shoes, etc. This is partly to compress soft tissues, clothing layers, etc. and be more connected to my gear. I also think of the pressure on top of your feet as a clamping force to hold you down to your ski. If you have less average pressure, then you have less clamping force, so with that mental model, I also take the paper above as not having loaded the BOA boot as much as the buckle boot, and thus not being a fair comparison (i.e., lower average pressure should result in lower max pressure, and in the paper we can see that the difference in peak pressure is about as big as the difference in average pressure... this could easily lead someone to think that the study is biased). I am really debating average pressure here, not pressure points. If you tell me that average pressure is not relevant to performance, then I would need to change my mental model.

Are you saying that BOA can give you better control of your boot without squeezing or developing a clamping force? If so, I think the paper could have used a better methodology to demonstrate that. For example, putting a given motion/force in at the tibia and observing the force output at the boot/binding interface. This kind of test is commonly done in robotics to measure a robotic arm compliance, backlash, etc.

Note also that the paper measure many real performance metrics like speed, g-forces and edge angle. However, resulting speed and g-forces are not listed, while edge angle are statistically not different. How can you produce more forces (4-6% as claimed) for much longer (as shown in the picture that Phil posted) without speed, g-force or edge angle changing?

 

[onenerdykid]

That sounds like marketing. I looked at a boa boot yesterday and it looks like the boa is attached at the same points a buckle would be.
I won't try them. I bought new boots last year and their gonna last until I'm old enough for a Nordica HF.

dm

That is correct on the medial side of the shell, at least for Atomic. Lateral connection points are different.

You ever wonder why every boot fitter says (and should say) "don't buckle your shell buckles tightly"? It is for this very reason- buckles wrap to an extent but then they collapse the shell. It is also a major reason why people struggle with high insteps in buckle-equipped ski boots.

 

[onenerdykid]

Very well done! "Falls short"

But seriously, I definitely do NOT have to experience things before knowing things. The parachute analogy is a perfect example. Why EXPERIENCE a parachute failure to KNOW it is a bad thing?

Why pay for the ski boots (experience) to know the impact on your bank account. Why not just KNOW that the bank account will be depleted by $699 if you buy them?

Did you go to the same school as Nancy Pelosi? House Speaker Nancy Pelosi (D-CA) said yesterday of health care reform legislation: “We have to pass the bill so that you can find out what is in it.”Mar 9, 2010

It's not that you need to experience falling without a parachute in order to know that it is bad, but you do need to experience gravity and the consequences of things falling in order to know & judge the consequences of falling without a parachute. This is basic epistemology (that is the study of knowledge and how knowledge itself is even possible), which I have studied as part of my master's degree. If you'd like to further discuss epistemology, knowledge, apriori knowledge, aposteriori knowledge, and synthetic knowledge we can move this to private messages in order to not clog up the BOA discussion.

 

[onenerdykid]

But the disappearance of independent adjustment (or non-appearance of independently adjustable pulley points) makes us think that BOA is a solution for mouldable shell and thin-wall shell boots only. Will BOA-optimisation consist largely of thinning the wrap?

If BOA is studied and shown clearly advantageous in boots with chonky racer-grade polyurethane most of my objections will go away.

I've personally been using it on my Redster CS 130 for 2 seasons, going into my 3rd (with the same prototype parts).

BOA's effectiveness is not dependent on thin-walled shells. For the same reason buckles are not dependent on thin or thick walled shells (same buckles are used for each shell type).

 

[Dave Marshak]

That is correct on the medial side of the shell, at least for Atomic. Lateral connection points are different.

So the problem is the connection point and not the buckle itself? Why not just change the connection point of the buckle? It seems like after 60 years they should have found the optimal connection point. Still not seeing the upside of the boa.

dm

 

[AlexisLD]

You ever wonder why every boot fitter says (and should say) "don't buckle your shell buckles tightly"? It is for this very reason- buckles wrap to an extent but then they collapse the shell. It is also a major reason why people struggle with high insteps in buckle-equipped ski boots.

Can you give a bit more detail about "collapse the shell"? I am not sure I understand that... (or the way I understand it could be fixed without using BOA)