Free-pivot Nordic touring??

[lilcliffy]

I have read many, many reports and opinions- suggesting that a free-pivot mode in a binding improves touring efficiency...

To be honest- this has always completely baffled me...

I increasingly even read opinions that an AT binding is more efficient at touring than a Nordic binding...

I don't really get it...

A traditional Nordic binding is purposely designed to have some resistance in it. This resistance is intended to offer either one, or both, of the following:

1) "Kick". When xcountry touring, a Nordic binding has resistance in it so that when you stride forward, the trailing foot/binding flexes- the resistance in the binding forces the camber in the ski downwards, engaging with the snow, and providing grip. A free-pivot binding does not facilitate the "kick" phase of a Nordic stride. The only way to get grip with a free-pivot binding comes from the ski base, and/or skin. The resistance of a traditional Nordic binding forces the ski's grip/traction zone to engage with the snow. The degree of flexibility/range of motion depends on the boot/binding complex (e.g. a NNN binding gives a fuller extension of the Nordic stride, than NN). Regardless- if you want an efficient "kick" when touring- you need some resistance in the binding.

2) Downhill edge control. In a traditional telemark, binding resistance forces ski camber to flatten, so that you can effectively edge and carve the ski. In a traditional telemark- the more edge-control you need, the more power you need- this comes, at least in part, from the resistance in the binding (obviously boot strength/leverage also plays a role). For example a 75mm-3pin binding becomes much more powerful, on the downhill, when you add the resistance of the cable (the cable also restricts the full extension of the Nordic stride, improving balance and control).

So- I am bit confused by the claim that a free-pivot binding offers better touring performance than a traditional Nordic binding...

The only conclusion I can come to is that skiers that are experiencing this, are primarily climbing and downhill skiing when on "tour". The performance advantage of a free-pivot binding when climbing cannot be underestimated. Once it gets steep enough , it is the skin that is providing all the traction- the resistance of a traditional Nordic binding is only serving to restrict the full range of motion- it is also potentially driving the tips deeper into the snow.

I see how the free-pivot is a performance advantage when climbing steep slopes- I don't see the advantage when K&G touring.

As an aside- does a "free-pivot" Nordic binding- such as the "switchback"- have a K&G touring mode that is NOT free-pivot? I have never used a "free-pivot" Nordic/telemark binding.

[MikeK]

I've not tried, but I've mentioned before I've talked to a few guys who ski in the ADKs who use free pivot switchbacks. One uses them primarily for skiing steeps, but with long approach tours. The other uses for touring (which baffles me a bit too).

The first guy, lets call him steeps, said they switchback sucks for skiing on flats. He's basically just walking. But he's also skiing in an area where approach trails get broken out quickly, and there are a lot of snowshoers. So he's probably referring to skiing in a snowshoe rut. What I got from him is you can make it up and down short hills, but you really want to lock them down for anything more than a quick drop. He's also touring with big boots (T2s I think), so even if he could get a good kick, that boot would kill any advantage the binding might have. He said for climbing they are the bomb, especially in untracked, steep stuff where the normal pin wants to drive the ski deeper in the snow. Everyone says this, and I believe it's the main advantage of the free pivot.

The second guy, lets call him tour, seems to love the free pivot for trail breaking. This seems to be his primary use for these. My guess is it provides him the same advantage that you get while climbing, the ski tip floats right to the top of the surface upon glide. He's using light boots, Alaska 75mm to be precise, so he doesn't have much resistance there. I'm assuming all the resistance he gets is from the snow. I'm not sure how often he locks them down, but I'm guessing for any serious descent he is, although that's not his primary focus in skiing.

I think if you did anything where you were exclusively trail breaking in deep stuff, it might be OK. You could probably break your tour into mini-climbs and descents and decide where it was most effective to switch back into fixed pivot mode.

Also with the switchback, you are kind of screwed with in fixed mode. It doesn't have pins so you can't remove the springs and rods. You could kick and glide against that but from what everyone says, it's way too much resistance.

[connyro]

I use free pivot bindings when I tour for turns, which includes touring several miles out to the goods and then doing laps up and down, and then touring home. With heavier gear (Excursions, SB, Vector BCs for example) The free pivot is a huge advantage. You are not exactly setting world speed records when touring on this type of setup, but you can get good kick and some glide: somewhere between true kick and glide and shuffling.

I remember when I first used a free pivot binding and was amazed at how different it felt when compared to 3-pins and I floundered at first. Without the resistance, striding and kicking was real weird feeling but after a little while, I adjusted and find the free pivot to tour just fine. You can get good kick with them as long as your boots/bellows/soles allow for some good flex so you can get the ball of the foot involved in the stride. Descending in the 'tour' mode is a bit tricky to get used to but really forces you to center your balance! Breaking trail and climbing is good with the free pivot but again, I found I had to adjust my technique in order to keep the ski tips where I wanted them.

For lighter gear, like 10th Mtns/3-pins/leathers, the resistance offered by the 3-pin bindings and leather boots really allow you kick and glide more like a true XC stride, and I prefer this to free pivot for longer and lighter tours. And to me, NNN-BC bindings/boots tour very similarly to 3-pins although 3-pins are far better for the down...and llilcliffy, the SB (or AXL) does NOT have a K&G touring mode that is NOT free-pivot: 'tour' mode for free-pivot and 'ski' mode for downhill full resistance.

[MikeK]

and llilcliffy, the SB (or AXL) does NOT have a K&G touring mode that is NOT free-pivot: 'tour' mode for free-pivot and 'ski' mode for downhill full resistance.

Just to be clear I was calling ski mode 'fixed pivot' (pivot is locked) and tour mode 'free-pivot' (pivot is free).

Oh and in the above example steeps was using Annums and tour was using Rossi BC110s.

[dnt_upton]

The only conclusion I can come to is that skiers that are experiencing this, are primarily climbing and downhill skiing when on "tour". The performance advantage of a free-pivot binding when climbing cannot be underestimated. Once it gets steep enough , it is the skin that is providing all the traction- the resistance of a traditional Nordic binding is only serving to restrict the full range of motion- it is also potentially driving the tips deeper into the snow.

I see how the free-pivot is a performance advantage when climbing steep slopes- I don't see the advantage when K&G touring.

Yes, that's right.

As an aside- does a "free-pivot" Nordic binding- such as the "switchback"- have a K&G touring mode that is NOT free-pivot? I have never used a "free-pivot" Nordic/telemark binding.

There are only two positions -- tour mode (free pivot) and ski mode (which you can still climb in, just as folks did about 8 or 9 years ago). For kick and gliding, "ski" mode would work better. But, if you have skins on because you've been climbing steeper terrain to get to that point, it ain't gonna matter. If you put Switchbacks on a pair of Voile Vector BCs or some other scaled ski, yes, you can go out and kick and glide in them. Purists may call bull shit.

[lilcliffy]

Interesting stuff...

I am certainly not a purist about anything- I would never call anything that works for someone "bullshit".

Seems the free-pivot is worth the loss of xcountry stride efficiency in a number of different situations, including but not limited to the following:

1) If you are doing a lot of steep climbing- free-pivot kicks ass! I know this from using AT- despite never trying a free-pivot tele binding.

2) I you are doing a lot of short yo-yo skiing. This one I had not thought of before. Connyro- your posts here- and on the other 3-pin hardwire thread- struck a cord with me. If you are out on "tour" searching for sweet, short downhill runs- then the free-pivot binding allows you to quickly climb and then switch to downhill mode (and over and over again). This makes sense to me.

So it seems that no matter what the application- in certain contexts, the climbing/turning performance of a free-pivot binding is worth the loss of xcountry Nordic-stride efficiency.

This confirms my original assumptions. It does not support AT enthusiasts that claim they can get better K&G performance than a traditional Nordic setup!

[lilcliffy]

The second guy, lets call him tour, seems to love the free pivot for trail breaking. This seems to be his primary use for these. My guess is it provides him the same advantage that you get while climbing, the ski tip floats right to the top of the surface upon glide. He's using light boots, Alaska 75mm to be precise, so he doesn't have much resistance there. I'm assuming all the resistance he gets is from the snow. I'm not sure how often he locks them down, but I'm guessing for any serious descent he is, although that's not his primary focus in skiing.

This is what doesn't make any sense to me.

When you are climbing a steep slope, the mechanical advantages of a free-picot are clear (both range of motion and tip-rise).

But K&G touring? The resistance of a traditional Nordic binding compresses the camber underfoot. On the flats, IMO/IME, whether the tip rises out of the pow is based on ski design- not binding resistance. In other words, a ski with rocker in the tip is going to have early tip rise on the flats- a stiff-tipped xcountry ski is not. A xcountry ski with traditional camber under foot, and rocker in the tip (e.g. S-Bounds, E-109, Madshus XCDs, etc.), is going to have early tip rise, regardless of binding resistance.

Even a trad backcountry-xcountry ski with very stiff-double camber (e.g Glittertind) has early tip rise during the glide phase, because of its soft tip. If one finds a ski like the Glitt sinking to the bottom, this is because it is narrow- not because of binding resistance.

When K&G touring on the flats- the resistance in a trad Nordic binding is only going to drive the tip down, if the tip is stiff and has no rocker.

Perhaps- your guy, "Tour", is using the first-generation BC-110 with the stiff tip? The new one is supposedly rockered in the tip.

All I know is that I get plenty of early-tip rise- in K&G touring- with a trad Nordic binding, as long as the ski is wide enough, and the tip is soft/rockered.

The only true experience I have with a free-pivot binding is touring in AT- which I find to be a form of walking at best- nothing like true Nordic K&G.

I have lost the bumper off NNN-BC bindings before (making them "free-pivot")- that is a weird experience. Not only can I not get an efficient "kick"- I also feel like my trailing leg is constantly falling as the ball of my foot, and toes flex beyond the point of no return. I always take a couple of extra bumpers on a long tour on NNN-BC.

[lilcliffy]

You can get good kick with them as long as your boots/bellows/soles allow for some good flex so you can get the ball of the foot involved in the stride.

Good stuff as always Connyro- but I am not following you...how can you get your ball of foot involved when you are in free-pivot mode?

[lilcliffy]

Descending in the 'tour' mode is a bit tricky to get used to but really forces you to center your balance! Breaking trail and climbing is good with the free pivot but again, I found I had to adjust my technique in order to keep the ski tips where I wanted them.

Why would you downhill ski in the "tour" mode? Isn't the "tour" mode free-pivot?

[lilcliffy]

And to me, NNN-BC bindings/boots tour very similarly to 3-pins although 3-pins are far better for the down...

I agree NNN-BC vs. 3-pin K&G performance is certainly closer than it is to a free-pivot binding (but I do find that NNN-BC offers better K&G performance- otherwise I wouldn't be driving myself crazy maintaining both NNN-BC and 75mm-3-pin setups!! )

I used to assume that 3-pin offered better downhill performance- I am no longer convinced of that. I get as much stability and power out of NNN-BC, as I do out of a basic 3-pin binding. Downhill skiing- what makes the difference for me, between NNN-BC and 3-pin, is the boot.

Add the strength, resistance, and power of a cable? Totally different world of downhill power.