Voile hardwire and switchback binding comparison

[EarlS]

A little over two years ago I bought Madshus Annums with Voile 3pin hardwire bindings. Part of the reason I chose these bindings was to see how much difference a cable would make for the kind of low angle touring that I do. Since many people using Voile 3pin cable bindings report that they do not ever use their cables for low angle touring, I was curious to see how much difference I would observe. I skied down a moderate slope with my Annums, 3pin hardwires and Scarpa T3s. First run on 3pins only, next run with hardwires cranked down tight, next run hardwires moderately soft, next run hardwire tight on one boot and soft on the other boot. There was no observable difference in control with the plastic boots. I have tried similar tests with my old resort tele equipment using Riva 2 cable bindings on slopes up to 25 degrees, i.e. blue runs at a resort, and did not seem to notice any difference there either. I concluded that cables do not make any difference in low angle touring (slopes less than 25 degrees) so I took the hardwires off and I now use 3pins only (saving ½ lb per foot).

This left me with a Voile 3pin Mountaineer mounted on top of the Voile V-120 riser plates (toe riser 2 cm thick, heel pad 2.8 cm thick). I thought of getting rid of the riser plates to save some additional weight, but the toe riser is ramped to compensate for boot rocker. Dave Mann notes that when you stand flat footed in a plastic boot, the rocker of the sole puts upward pressure on the binding, and this upward pressure can cause the front screw on a 3pin binding to rip out of the ski. To test this I put my boot in my binding with the riser plates and found that the heel of my boot rests 2.5 cm above the heel pad. I can push the boot heel down on the heel pad with minimal force, so I am not worried about putting excessive upward pressure on the 3pin binding. I then put my boot in a standard Voile Mountaineer with a 1 cm heel pad height. In that case the heel of my boot was 3.75 cm above the heel pad. When I pushed the boot heel down on the heel pad it required quite a lot of force, which might be enough to cause trouble with the front binding screw after extended use. I guess I will keep the V-120 risers just to compensate for the boot rocker; I am not concerned about "boot out" or the small additional torque that the riser provides for edging because the Annums are not high performance skis for use on hardpack.
If I were to get 3pin bindings for a new ski, I would buy some of the "Voile 3pin Cable Traverse Risers" which also have a 3 degree ramp angle in the toe riser to compensate for boot rocker. That 3 degrees translates into about 1 cm at the boot heel.

Last March I rented some Rossi BC110 with switchback bindings to see if I might like the switchbacks. I took them on a 3 mile rolling trail which leads to a nice 20 degree downhill run through an open meadow. I set the tension on the cartridges to provide about the same amount of heel return force as my 3pin bindings give. In the pivoting mode the heel lifts freely, pivoting at the toe and, as everyone knows, this is really nice going uphill because you do not have to lift your heel against that heavy return force on every step. On flat areas it was possible to step forward and glide while in this mode. I would like to call this "striding" to distinguish it from kick and glide. Some have called it "shuffling" but I think "striding" is a better name because the skis were definitely gliding on every step after I pushed forward. On skins there would be no glide and the term "shuffling" would then be appropriate.

When I put both skis in the "non pivoting" mode they felt exactly the same as the kick and glide that I do with my Annums on 3pins. This is not a surprise because I had set the heel return force to equal that of my 3pin bindings, and the duckbill of the boot has about the same amount of free play up and down in both switchbacks and my 3pins. I then asked "what is the difference, what am I doing during kick and glide that makes it feel different from "striding" ? To explore this I set one ski in the pivoting mode and the other in the non pivoting mode. I discovered that in the kick and glide motion I leave the trail ski extended back for a brief period of time (maybe one second) as I push off and glide forward on the leading ski. When the trail ski was in the non pivoting mode, the ball of my foot was pressing down on the ski due to the heel return force. This created a forceful connection between boot and ski which increased control over the trail ski and significantly increased the amount of forward push that I could deliver to the lead ski. When the trailing ski was in the pivoting mode, the boot lifted freely, pivoting at the toe. This reduced control over the trail ski and I could not push off as well because there was nothing to push against. More force delivered rearward would only pivot my foot a bit more, rather than pushing me forward off the rear ski. My body mechanics during kick and glide were a revelation to me.

The switchbacks have risers which look almost the same as those on the Voile 3pin hardwires but the riser height is 2.5 cm versus 2 cm for the hardwires. With my T3 boot resting in the binding, the boot heel was 2 cm above the heel pad and was again very easy to push down onto the heel pad, just as it was with my hardwire bindings.

It is obvious that kick and glide in plastic boots is not the same as using NNNBC or 3pins with leathers because the boot sole on plastic boots simply does not flex. There is some flex in the bellows, but it is clear that a large amount of the "flex" when using plastic boots is due to fact that the duckbill is not firmly clamped at the toe. If I put my boot in the binding with the ski sitting on the floor, I can raise and lower the boot heel a huge amount (6.5 cm above the heel pad) without ever compressing the bellows. This was true of the toe box on the switchbacks as well as my 3pin bindings.

I really liked the switchback because there are some trails where I go uphill for a long way with little or no opportunity for kick and glide and eliminating the heel return force would be very beneficial. You can also do real kick and glide on rolling trails if you choose to set the heel return force about the same as it would be on a 3pin binding. It is very easy to switch between the two modes on the trail. The only disadvantages that I see are the cost and the fact that the switchback weighs almost 2 lbs more than a 3pin binding.

[MikeK]

Some very interesting observations Earl, thanks for sharing. I'm assuming your notes from Dave Mann came from the old Ttips? Do you have any reference?

It's my understanding that cables function a bit different than Dave describes, but I have no real experience with them, only what I can surmise from the physics of them. Anyway, it seems to me torsional stiffness does not change with leathers as stiffness changes very little with tension or compression, but rather adds a preload to the boot. This preload pushes the ball of the foot flatter onto the ski depending on where the pivot of the cable is. The cable and the boot have almost exactly the same stiffness as they did when the boot heel is on the riser, but the load going through the boot changes. It's a subtle difference that people often confuse.

Also because the pivot on most all of those bindings is rearward of the pivot of the duckbill, this creates a moment, or torque that tends to drive the tip of the ski downward into the snow. The greater this moment arm, the more active, or more torque will be created with the same stiffness spring and heel lift. I'm not sure exactly what this does except to pressure the tip of the trailing ski more and help it initiate turning better. It's my experience skiing only "neutral" bindings i.e. NNN/BC and 3 pin, that it's simple a matter of getting enough weight on the rear ski to make it want to bend and carve. If you don't weight it enough, it either wants to go straight, or skid depending on how much edge angle you've given it, and the type of snow i.e. high grip corn/mash or low grip hardpack/ice.

The other stuff you say about plastic, rocker launch force and K+G with the heel throws makes a lot of sense actually.

[lowangle al]

I also think the two bindings ski the same until you either put the SB in free pivot or remove the heel throws on the HW.

Although I have skied the SBs in tour mode for K&G with good results it is not something I do often, prefering the "normal" feel of the K&G w\o it. I find I get more benefit from skiing the HW w\o the heel throws for more efficient touring than the SBs in free pivot, unless I were skinning.

As far as dh performance of the HW I notice a big difference with or w\o the heel throws. The thing I get out of the cable on a binding is having more control of the ski while it is unweighted. This can be anytime from sidestepping on the up to having the ski start turning during the unweighted transition part of the turn, before getting weight on it. This results in smoother quicker turns for me.

[EarlS]

Hi Mike - I have looked through all my notes and I am not able to find the reference to the comment by Dave Mann. Since you suspect it may not be correct I am worried that I am remembering it wrong. I will modify my original post to include only references that I can actually find. Sorry about that.

[MikeK]

It's fine Earl, I was just curious.

[Rodbelan]

I do not think you would find much difference between a 3 pin HW and original SB... Same cartridge, similar pivot location. Maybe the bail that maintain the duckbill tight in HW makes it more secure, solid... it could help edging. If you want more heel retention, you need the SB X2 with stiffer cartridge and a further back pivot location...

[rongon]

I do not think you would find much difference between a 3 pin HW and original SB... Same cartridge, similar pivot location. Maybe the bail that maintain the duckbill tight in HW makes it more secure, solid... it could help edging. If you want more heel retention, you need the SB X2 with stiffer cartridge and a further back pivot location...

For some reason, the 3pinHW makes my plastic boots' bellows flex in the wrong place, which causes bad toe bang. I find that the original SB in ski mode feels exactly the same as the old Voile Hardwire (orange color). The 3pinHW feels much stiffer to me than either the original SB or the old HW. But that is likely a product of my weird feet that require Crispi boots.

For me, the SB X2 is perfect with 3-buckle boots and a ski with mid-90's waist.

FWIW...

[lowangle al]

The X2 is a great binding, but I find it inefficient for the kick and glide, too much tip pressure.