The Tecnica Zero G Tour Pro boot and an ATK Crest 10 binding. The binding delta is ~10.5mm.
Keep it simple. Binding delta, the difference in height between the heel and toe (with the heel higher than the toe) impacts how we ski. From a centered stance to desiring more forward lean, we dissect bindings deltas.
A sports fan, are you? If that is your jam, and regardless if you are number-phobic or number-philic, sports have adopted the sabermetrics Kool-Aid. Recall baseball scorecards and the necessary decoder ring to read them. No? Don’t worry. We’re moving on too. Sports, gear, and biomechanics are having their analytical heyday; we’re not immune to better experiences through better number crunching. Soul sports and quiet sports (backcountry skiing and splitboarding) crunch numbers too.
Binding Delta
We tend to focus and obsess over gear weight. And sometimes, we hone in on angles and height differentials. One sensation many skiers notice is ramp angle: the angle from the middle of the heel pins to the toe pins. This impacts how we pressure a ski as it determined the difference in height between the boot heel and toe. To minimize variables as we introduce ramp angle, imagine the same boot is used with two different bindings. You’ve got a Plum R-170 on a spring setup with a delta of +4.2mm (the heel-pin center is 4.2mm higher than the toe-pin center) and an all-around/powder ski with an ATK Crest 10 (and brakes) with a delta of +13.2mm. That’s nearly a centimeter.
With all the numbers tossed around, I’m experiencing nearly a centimeter greater delta with the Crest 10. I cannot say I’ve fretted about this difference. My stance preference, though, depends on the conditions. I like to dance around with my stance options in soft snow, bottomless powder. Depending on how much float I’m experiencing and how I want to drive the ski, there are times I want the option for a more centered stance and times when I drive my shin, increasing my ankle flexion, to drive the tips into and out of a turn. With a more neutral binding delta, a more centered stance, generally, is easier to actualize. This may be something to discuss with a local shop if you are waffling between binding options. (And oh yeah, there are riser options to think about as well…..)
Here the Black Diamond Helio 200 LT (a rebranded ATK unit) has a binding delta of ~1.7mm. Compared to the image of the same boot in the G3 ZED binding, note a slightly larger gap under the heel in that image.
The G3 ZED has a binding delta of ~4mm with these 297mm BSL Dynafit Blacklights.
The Scarpa Alien 1.0 is locked onto the Hagan Ultra World Cup binding. The unit here is mounted on a heel adjustment plate. Without the plate, the binding delta is ~0. With the heel plate, the delta bumps to ~4.5mm.
Adding in BSL
Let’s throw in the variable of BSL, or boot sole length, when considering binding delta. (Look for the BSL marked on the boot shell.) For example, I ski a 27.5 Salomon S/LAB MTN Summit; the BSL is 298mm. I also use a Tecnica Zero G Pro Tour in a 27.5.; with a 313mm BSL. The difference between the BSLs is 1.5cm. If we use the same ski/binding setup but wear the MTN Summit on the left and the ZG Pro Tour on the right, the effective delta’s are the same on the left and right, respectively. Still, the ramp angle (from heel pin center to toe pin center) is slightly decreased on the right ski since that boot has a longer BSL. You may not feel the difference, but if you are keyed into slight variations in gear, you likely can. Your stance will be slightly more upright in the longer BSL boot than in the shorter BSL boot.
Are we ready to throw all this BSL, delta, and ramp-angle-speak out the door? Not quite yet. But the experiment is much easier to zero out if we discuss the same boot in the same BSL and only swap out bindings with different deltas.
For example, the toe pin insert locations aren’t standardized between boot brands. The differences may only be a few mm fore or aft on the boot shell relative to another brand boot, but it is a difference; maybe an unnoticeable difference. It all depends on you.
Also, take a look at the Dynafit TLT 8s with the snub nose design; the toe pin inserts, relatively speaking, are further fore than in the newer Dynafit TLT Xs and BlackLights, which reintegrate a traditional boot toe lug (thank you, Dynafit).
Then some boot soles are more rockered than others. And not all boots have identical forward lean. I need a beefy rear cuff shim in my Zero G Pro Tours to increase the forward lean to my liking. Ok, yeah, lots of variables when swapping from boot to boot. But know that boot selection will affect how you experience binding delta and the associated ramp angle.
To the Future
Binding delta is one aspect of the gear and biomechanical puzzle. Things get noisy, complicated, and muddied no matter how you slice it; it is less simple as we introduce more variables.
And we have yet to mention adding a toe shim under the binding’s toe unit. A toe shim will increase the overall stack height of the toe unit and decrease the binding delta. If you experience too much forward lean, and want to correct for a more centered stance, the addition of a toe shim can be a low cost, low effort solution.
Why have I spent over 700 words pondering binding delta? I’ve got some biomechanical changes to consider as I’m about 4.5 months into an ACL/meniscus repair. And yes, most of it has gone to plan. But no matter how much stretching I do, the Patellar Tendon in the reconstructed knee gets mighty tight. How tight? Tight enough that I’m starting to think about binding delta, ramp angle, boot selection, and a more upright stance to take some pressure on the Patellar Tendon once I begin skiing again. Pipe dream? Maybe. Glass half full? Cautiously optimistic, half full.
The nice thing is that precisely BECAUSE the boot variables add to the binding delta, we are only concerned with the net result.
So, I simply measure that net result: the boot board angle inside the boot, with the boot in the binding.
This way you can compare various bindings (skis) or various boots, or both.
For me, I use it to compare both my lift skis (1 boot) to both my touring skis (with a different boot). My thought is that if I set them all similar, I will have an easier time transitioning. Also, I use the set up I feel most comfortable on as my baseline. Other people might not want the same angle across their set ups. No matter, the measuring stays the same.
I find the easiest way to measure this is by placing the ski on a flat surface, then measuring with a clinometer off the vertical arm of an L-square inserted into the boot, which is clicked into the binding.