Post
by MikeK » Thu Mar 26, 2015 9:53 pm
Maybe I'm going to dive off topic here a bit but from purely a mechanical standpoint, nothing to do with 'feel' or anything like that, I believe the cable, or wire/springs, or whatever, depending on the actual pivot mechanics can do a couple things:
First: Increased fore stability. Resistance to raising the heel gives you more stiffness from falling forward. Aft stability is still all in the boot.
Second: Related to the first - increase weight to the front of the rear ski. The reaction force to lifting the heel and the cable stretching is the tip of the ski pushing into the snow more. There's all sort of stuff that can be done by changing the pivot points ect to alter the mechanics of it, but it's almost always there. Even the stiffness from flexing your boot causes this phenomena with no heel restraint. Don't believe me? Try lifting the ski in the air and getting your heel to lift significantly off the the heel plate. It can't without pushing on the tip. The stiffer the pivot torque is, the more force goes on the ski, particularly the front of the ski.
Third: Laterally stability. This affect is pretty minor in most cases. You could work out the component of force that keeps acts laterally along your boot and add that as an effective stiffness to the system, but it's not a great amount. Stiffer springs and cables give more force and resist lateral heel motion, but probably not as effectively as a stiff boot does.
The other stuff seems fairly minor to me.
At any rate, skis and bindings are not a great mystery in terms of mechanics, they are pretty simply machines. So yeah these things do have an affect, it just depends on whether you need it or want to mess with it.
Most of us that forgo the cable do so for the reasons stated previously. We just want to ski up and down and don't want to fuss with taking it on or off. Touring with a cable in deep snow with just drive your tips deep into the snow with every stride. This is why free-pivot bindings were such a 'revolution' for telemark. The ski tip is allowed to float back up with every stride so you can actually float on the snow, not dig holes with the shovel. The steeper you try to go up, the more this= happens, but it still happens even on flats to some degree... the stiffer your boot flex is even with a pin binding, the more likely it is to stay sunk in the snow... it all comes down to the tip force I was talking about in reason two above.
So if you really want the best of both worlds, and just plan on climbing, and descending, then look into the switchback bindings. You can flip the switch to lock them with your pole - not farting around with latching cables, and have a free pivot for climbing and a very strong wire/spring heel for descending.
It really depends on what your after though. If you plan on covering some flat ground and your descents aren't that long or steep, just learn to ski with the pins and kick and glide with the plastic boot. You'll get around fine - faster than snowshoes for sure.
As connyro pointed out in another thread, there are all sorts of stuff you can do with XCD... you'll figure it out. The skis you bought may not be ideal for all conditions but in powder with plastic boots they'll be fun. Skiing on hard or icy snow is hard no matter what XCD ski you use... skinnier skis tend to work better because they impart less torsional load to the ski structure (less leverage) and edge quicker. That's not to say a Madshus Voss or E89 is a good choice for a hardpack, dh focused ski. They are a good xc, touring focused ski for those conditions. To get a wider ski to work in those conditions it needs to be thicker, stiffer and thus heavier. Heavier skis require more force via boot and binding to control... thus the vicious cycle. In the end you may just want to look into a narrow, shaped telemark ski like lilcliffy is eluding to, for the harder conditions.
However, new ones can be had directly from Italy on ebay. Not sure about duty etc but the price looks good.
