Binding heel piece and ski tail stiffness

[Orthoski]

This is a question that arose in the ON3P thread and I was curious to hear people's thoughts (thanks to those that already chimed in on the ON3P thread). Does the type of heel piece affect the way the tail flexes and makes it more or less forgiving?

I can theoretically imagine that the farther back a binding's heel baseplate extends beyond the ski boot, the more it will stiffen the tail, with this effect heightened on skis that are already mounted more posteriorly (i.e., less freestyle skis). Has anyone really noticed this in vivo when mounting an FKS/Pivot that have a shorter mounting length vs. an STH2/Axial/Marker type binding? Do the tails really become a little more forgiving with a Pivot binding because they now have an incrementally longer flex distance, or is this a placebo effect?

Curious about people that have actually run this experiment....

[rip]

I wouldn't necessarily say it makes the tails stiffer, I mean technically it does by a little bit but I can notice a difference for sure. Mainly loading up the tails to pop off a roller or bump, gotta lean back a little bit more exaggerated with a solly heelpeice vs a pivot and the ski doesn't flex right at your heel like it does with a pivot.

[toast2266]

I wouldn't necessarily say it makes the tails stiffer, I mean technically it does by a little bit but I can notice a difference for sure. Mainly loading up the tails to pop off a roller or bump, gotta lean back a little bit more exaggerated with a solly heelpeice vs a pivot and the ski doesn't flex right at your heel like it does with a pivot.

Agreed. It's less about how much the ski is flexing and more about where it's flexing.

[Orthoski]

As I've been thinking about it, the binding baseplate is an extension of the bottom of your boot. Functionally, it lengthens your BSL unless there were motion at the binding-boot interface so that there's flexibility. So if the functional BSL includes the binding mount area, the longer the heel piece baseplate, the more it would shift the functional boot center backwards compared to where the intended mount is located, no? Wouldn't the length of the baseplate affect where you would want to mount your ski based on the manufacturer's recommendation?

And the reason it may stiffen the ski tail functionally is because now you're trying to bend a shorter tail on the ski (take the same 2x4 and cut two separate lengths - they have the same elastic module but the longer one will be easier to bend a given absolute distance if you're holding it at the ends).

The reason I theoretically wonder about this is that we spend so much time on this forum talking about mounting 1-2cm forward or back of the manufacturer's recommended line, whereas the difference in heel baseplate length between companies (more so than toe) is way more than this. Are we mounting our skis too far back when using a Solly or Axial heel piece? Or is there enough flexibility at the binding-boot interface that it counters all of this?

[Mudfoot]

That is one the reasons Look/Rossi Pivots are so popular. The binding basically ends under the heel of your boot and does not inhibit the flex of the back of the ski. The opposite is a rental/demo binding with a long track sticking back and screwed into the tail. The difference can be 3+ inches.

[waxloaf]

As I've been thinking about it, the binding baseplate is an extension of the bottom of your boot. Functionally, it lengthens your BSL unless there were motion at the binding-boot interface so that there's flexibility. So if the functional BSL includes the binding mount area, the longer the heel piece baseplate, the more it would shift the functional boot center backwards compared to where the intended mount is located, no? Wouldn't the length of the baseplate affect where you would want to mount your ski based on the manufacturer's recommendation?

And the reason it may stiffen the ski tail functionally is because now you're trying to bend a shorter tail on the ski (take the same 2x4 and cut two separate lengths - they have the same elastic module but the longer one will be easier to bend a given absolute distance if you're holding it at the ends).

The reason I theoretically wonder about this is that we spend so much time on this forum talking about mounting 1-2cm forward or back of the manufacturer's recommended line, whereas the difference in heel baseplate length between companies (more so than toe) is way more than this. Are we mounting our skis too far back when using a Solly or Axial heel piece? Or is there enough flexibility at the binding-boot interface that it counters all of this?

I think you might be overthinking this one. Your overall point about flex is a good one, and as already noted, is a point many have made about the pivot/fks for years. Mount point is about getting your forefoot/midfoot in the right spot on the ski to engage sidecut and have proper balance. I dont think what is going on behind your heel has much to do with that


Sent from my iPhone using Tapatalk

[ZomblibulaX]

A few years ago I had two pair of Superbros, one with fks 155, the other with px 18, both mounted on the line, and there was a noticeable difference in the end of the turn. I wouldn’t say the px stiffened the tail substantially, but specifically in hard, short turns on hardpack I had to push farther in to the tongue of my boot to get the same response out of the pair with the px 18, but this is a pretty specific scenario. It certainly wasn’t enough to make me want to adjust the mount point but on a different ski you might have different experience.

I’d agree with your assessment but the difference is not very dramatic. I think if you really want to tell much difference you either need a soft, pretty short ski where there’s likely to be more of an impact, or A/B between pivots and, say, a frame binding like a guardian where your mounting platform is a lot longer. There is motion at the binding/boot interface because as the ski flexes it loads up your forward pressure springs. It’s not a lot, and your boot is going to impede the flex of the ski enough as to largely negate it.

[glademaster]

All of the fanboys here will say I'm wrong, but that doesn't change reality. The issue here isn't the binding, it's that ON3P's flex patterns are not very refined. I'm not sure whether this is due to core profiles or the laminates they use, but it's the conclusion I've reached. They're great crud skis with generally pretty high build quality, but no objective analysis could lead to them being called truly great skis.