Non-toe-release pin tech binding in bounds- Don't do it

[ted]

Given the likely explosion of the backcountry market, I think this deserves it's own thread.

This discussion was started here-

Alpine-Touring hybrid setup

I have no experience in backcountry/touring skiing, but as an expert experienced alpine skier, I am intrigued by the range of hybrid bindings to expand my horizons beyond the downhill options at the resort. I am based in UK, so I don't have local mountains to drive and hike to - this exercise...

www.pugski.com

Thanks to Cody Townshend for bring this to the forefront in the blister interview here-

Cody Townsend on Coffee Makers, Bindings, & Beacons (Ep.119) | Blister

BLISTER | GEAR:30, Podcasts | October 23, 2020 | The most honest & in-depth reviews of outdoor gear

blisterreview.com

“They’re f#$@ing dangerous”.

Extensive info here-

Ripping Ligaments & Snapping Bones - Tech Binding Release Testing - The Backcountry Ski Touring Blog

Alpine touring 'tech' ski bindings, carefully tested and compared to alpine binding safety release including knee and bone injuries for backcountry skiers.

www.wildsnow.com

Dave Dodge and Bill Doble explain the physics here-

Chairlift Chats: How Safe Are Alpine Touring Bindings?

dodgeskiboots.com

I'm pretty sure this comes from Rick Howell- The ski industry learned in the 70's that toe release is absolutely necessary to prevent spiral tib-fib fractures.

Somewhere Rick has also posted that the tib-fib fractures occurring with tech bindings without toe release are often more serious(not clean) and often involve the tibia plateau.

 

[Unpiste]

Should the title have been "non Toe release"? I don't think in-bounds really matters. I'd certainly rather have a tib-fib fracture in-bounds if I had the choice.

A list of bindings to avoid, or bindings that tested well would be helpful.

 

[pchewn]

That chairlift chat with Dave Dodge is so full of crap.

Just a few things:

• He's trying to explain why AT bindings are unsafe for downhill skiing. None of his explanations are unique to AT bindings. All of his "speed" and "distance to the force" explanations are equal for AT and regular downhill bindings.
• He does not understand the concept of torque and how the torque in a rigid body can be applied or reacted to anywhere on the rigid body and have an equal effect.

 

[pais alto]

Karen’s take on touring bindings.

 

[Philpug]

That chairlift chat with Dave Dodge is so full of crap.

Just a few things:

• He's trying to explain why AT bindings are unsafe for downhill skiing. None of his explanations are unique to AT bindings. All of his "speed" and "distance to the force" explanations are equal for AT and regular downhill bindings.
• He does not understand the concept of torque and how the torque in a rigid body can be applied or reacted to anywhere on the rigid body and have an equal effect.

@Dave Dodge is the President of ASTM, I think he has a very good understanding of the mechanics of the release aspect of a binding.

 

[pchewn]

@Dave Dodge is the President of ASTM, I think he has a very good understanding of the mechanics of the release aspect of a binding.

He is not the president of ASTM. Katherine Morgan is the president of ASTM. https://www.astm.org/ABOUT/staffleadership.html

He may have a good understanding, but the video did not show that.

 

[Philpug]

He is not the president of ASTM. Katherine Morgan is the president of ASTM. https://www.astm.org/ABOUT/staffleadership.html

He may have a good understanding, but the video did not show that.

Sorry, the Chairman of ASTM Binding Testing. (0:28 into the video)

 

[James]

He may have a good understanding, but the video did not show that.

Have to agree. That’s the problem with videos. It can take a lot of back and forth to get the info out of somrone. More to be understandable. In print it ‘s easier, but not easy, to put it together coherently and the subject can easily review it. All that takes much more time and effort though.

 

[Dave Dodge]

That chairlift chat with Dave Dodge is so full of crap.

Just a few things:

• He's trying to explain why AT bindings are unsafe for downhill skiing. None of his explanations are unique to AT bindings. All of his "speed" and "distance to the force" explanations are equal for AT and regular downhill bindings.
• He does not understand the concept of torque and how the torque in a rigid body can be applied or reacted to anywhere on the rigid body and have an equal effect.

You are correct in saying "...concept of torque and how the torque in a rigid body can be applied or reacted to anywhere on the rigid body and have an equal effect" only if the "torque" is a couple (pure moment). However when the load is a force/couple (force at a distance) the pivot axis can make a big difference if the tibial axis and kinematic pivot axis of the binding are displaced form each other. If they are aligned then it make no difference. Alpine bindings with pivot axis near the tibial axis perform the same whether the load is a pure moment or a force/couple. Most Pin/Tech (not all) bindings do not perform the same as Alpine bindings. The difference is largest when the load is close to the foot. When the load is close to the foot and you are going slow the most likely outcome is that your body spins around without applying much of a moment to your tibia. However when you are going fast your body has too much inertia and something else might give. When skiing the load is almost always a force/couple.

force couple system examples - Google Search

 

[slowrider]

My knee started hurting just reading that.

 

[Philpug]

In talking to @Daron Rahlves one of the reasons for the Shift was for downhill safety along with performance.

 

[P-Ute]

@Dave Dodge's explanation made my tibias hurt. Another good reason to take it easy in the backcountry or you may be living in the "moment," but not in a good way.

 

[Ken_R]

That chairlift chat with Dave Dodge is so full of crap.

Just a few things:

• He's trying to explain why AT bindings are unsafe for downhill skiing. None of his explanations are unique to AT bindings. All of his "speed" and "distance to the force" explanations are equal for AT and regular downhill bindings.
• He does not understand the concept of torque and how the torque in a rigid body can be applied or reacted to anywhere on the rigid body and have an equal effect.

I was thinking the same thing. But its not that simple.

Speed is the "enemy" for sure. I always take it down a few notches when skiing in the BC. The farther I am from the trailhead the easier I take it.

 

[pchewn]

You are correct in saying "...concept of torque and how the torque in a rigid body can be applied or reacted to anywhere on the rigid body and have an equal effect" only if the "torque" is a couple (pure moment). However when the load is a force/couple (force at a distance) the pivot axis can make a big difference if the tibial axis and kinematic pivot axis of the binding are displaced form each other. If they are aligned then it make no difference. Alpine bindings with pivot axis near the tibial axis perform the same whether the load is a pure moment or a force/couple. Most Pin/Tech (not all) bindings do not perform the same as Alpine bindings. The difference is largest when the load is close to the foot. When the load is close to the foot and you are going slow the most likely outcome is that your body spins around without applying much of a moment to your tibia. However when you are going fast your body has too much inertia and something else might give. When skiing the load is almost always a force/couple.

Yes, that makes sense. It's too bad the video does not say that. In fact, the video says very little about the binding's operation at all.

 

[jmeb]

. Most Pin/Tech (not all) bindings do not perform the same as Alpine bindings.

This is an important take away. Most pin/tech do not have lateral toe release, some do. And glad to see it stated by someone like @Dave Dodge because the original video I think was before the Vipec/Tecton/Shift/Duke PT had all seen a lot of use.

I'm not saying that Vipec/Tecton are the same design as the Shift/Duke PT. But they do offer lateral release at the toe that has passed TUV testing for consistency of release (again, NOT to the alpine standard.)

In short -- from a tib-fib safety perspective I think there are a few major categories (assuming all are functioning correctly)

From more safe to least safe
- Alpine bindings and alpine bindings w/ pin-uphill: Duke PT and Shift
- Lateral toe release pin-tech: Vipec, Tecton (and for the truly odd, the Trab)
- Non-lateral toe releasing pin tech bindings.

 

[chopchop]

To me the essential message here is always know the limits of the equipment you are using at that moment. Also why a two-binding quiver for the BC is not a bad idea (eg. CAST and pins).

 

[Dave Dodge]

To me the essential message here is always know the limits of the equipment you are using at that moment. Also why a two-binding quiver for the BC is not a bad idea (eg. CAST and pins).

If people are willing to trade off downhill release function for superior uphill performance that is their choice, but the info to make that decision should be out there for everyone to see.

 

[ted]

If people are willing to trade off downhill release function for superior uphill performance that is their choice, but the info to make that decision should be out there for everyone to see.

That is exactly the reason for my post. Trying to get the word out.

 

[ted]

Should the title have been "non Toe release"? I don't think in-bounds really matters. I'd certainly rather have a tib-fib fracture in-bounds if I had the choice.

A list of bindings to avoid, or bindings that tested well would be helpful.

Thanks to whoever fixed my typo.

 

[locknload]

This is an important take away. Most pin/tech do not have lateral toe release, some do. And glad to see it stated by someone like @Dave Dodge because the original video I think was before the Vipec/Tecton/Shift/Duke PT had all seen a lot of use.

I'm not saying that Vipec/Tecton are the same design as the Shift/Duke PT. But they do offer lateral release at the toe that has passed TUV testing for consistency of release (again, NOT to the alpine standard.)

In short -- from a tib-fib safety perspective I think there are a few major categories (assuming all are functioning correctly)

From more safe to least safe
- Alpine bindings and alpine bindings w/ pin-uphill: Duke PT and Shift
- Lateral toe release pin-tech: Vipec, Tecton (and for the truly odd, the Trab)
- Non-lateral toe releasing pin tech bindings.

Thank you...this was kind of the translation I was looking for. This is such an important discussion especially as the BC bindings proliferate in and out of the resort all across the mountains. I for one, do NOT, enjoy skiing my tech bindings on groomers in the resort. I can't say I'm a good enough skier to describe why I don't like them...they don't feel as comfortable when I have to lay the ski over but others may feel differently. I also feel like I tire out more quickly when skiing them aggressively vice alpine bindings. I know I want a binding to release in lots of different directions (when acted up on by appropriate forces) when speeds are higher and crowds are bigger.