NOTE: Article below is published here for background, current backcountry skiing binding flex tests are HERE.
The Naxo NXO1 and Diamir Freeride randonnee AT bindings are well engineered solutions to creating an AT binding that tours well but still behaves like an alpine resort skiing rig. Yet anything can be tested!
As Randonnée bindings become more alpine-like in look and performance, it’s inevitable that the way they hold your foot to the ski will become an issue. This is especially true of the Naxo and Freeride plate bindings, two offerings that compete to be the “one-rig” setup of choice that can perform both at the ski resort and while backcountry climbing.
Scientific testing of Naxo and Fritschi binding slop and foot retention is difficult. Most factors can be equalized, but adjustment of the toe jaws up and down makes a significant difference in boot movement — and there is no exact way to set a perfect toe jaw height as boot rubber compresses and plastic flexes. More, the heel release tension (vertical release) setting may influence lateral boot deflection, as the boot heel tilting during torque will tend to lift the heel jaw. Thus, even the vertical release DIN needs to be exactly the same for perfect comparative testing, and simply setting it by the number on the binding is not accurate enough — it would need to be set according to a measuring machine.
Adding to the confusion, the shorter the Naxo or Freeride plate is in relation to your boot, the less it will torque. But because the two bindings come in sizes that have varied relationships to boot length, certain boot lengths might do better in the Naxo; others in the Freeride.
All that said, a seat-of-pants comparison of Naxo and Freeride is possible. One can simply place two skis side-by-side, snap the same size boot in either binding, with the same DIN and best toe-jaw height adjustment possible, then wriggle the boots. Beyond that, one could clamp both skis to a bench, and rig up a crude measuring device to reach some sort of repeatable comparison between the two bindings.
Recently, I spent some quality time in my shop, and did both types of tests.
It was an interesting project. First, let me be clear that both bindings have quite a bit more movement than a good quality alpine binding. Yet truth be told, it’s surprising how much slop their is in an alpine rig as well. Check one for yourself.
Beginning the test
For the tests described here II used the same “size” bindings, a medium 04/05 Naxo NX01and a standard Freeride of ’04 vintage (as far as I know, the beef of last year’s Freeride is the same as this year’s, so for comparison it worked fine). Length (size) of the binding is important because the longer the binding plate, the more it will twist and deflect under load. Thus, using the shortest binding size possible for a given boot is the way to go. In my test case, neither the short size Naxo nor Freeride would have fit my test boots — so my comparison is realistic. In real life when buying bindings, be sure to compare and see how short you can go. If you discover that the shorter size of one of the bindings will fit your boot, use that as part of your buying decision — it will be lighter and torque less, and possibly be more durable since the shorter plate may place less leverage on associated binding parts.
We received complimentary bindings from the suppliers of both products, and receive equal product support from both companies, so my “swag bias” is equal. More, I don’t favor either binding as a one-rig solution. They both worked well during my field tests, and frankly, both ski downhill fine for my style (less aggressive but precise and smooth, with occasional bursts of as much power as a middle aged and fit recreational skier can muster). All that said, I prefer tech bindings so all the skiing I do on frame bindings is dedicated to testing them.
Seat of the pants
Both the bindings were mounted on skis of similar width and flex, and fixed securely to my solid workbench using steel bars and clamps. I used the same boot for all tests, a Garmont Mega Ride that I kept buckled the same. I adjusted both bindings to the same DIN number (7), and did the best job I could on the toe jaw height setting, with my goal to adjust the bindings as similar to each other as possible, while doing it in such as way that stayed with manufacturer’s specifications and instructions.
I then simply clamped the Garmont boot in the binding and wriggled it side to side in a way that tilted it left/right. First impression was that BOTH bindings had quite a bit of movement. The Freeride toe jaw could be seen wriggling and rocking under the head of the height adjustment screw, and the whole binding could be seen twisting, and when the boot was tilted hard to the side, the tilting of the heel would lift up the binding heel unit. The Naxo NX01 had similar movement that was easier to induce. The NX01 toe jaw could be seen flexing, the plate could easily be seen twisting, and the tilting of the boot lifted the heel unit.
Again, while I could feel the Naxo was easier to move, the difference was too small to allow any accurate assement. Thus, I needed something that approximated a more scientific approach. To that end, I built a test lever consisting of a vertical steel post and attached horizontal lever arm. I buckled the post in the boot, and weighted the arm with the same amount for each test. To quantify, I simply measured the difference in deflection of the vertical arm while weighting and un-weighting the contraption. The process was a bit crude, but the results were repeatable (a prime qualification for any worthwhile test).
First, let me say that a better test would graph resistance through a range of motion, rather than static deflection. Thus, my test was only a crude and preliminary read on binding deflection. Nonetheless, the numbers reflect my “feel” test. With what I thought to be reasonable torque for testing (yielding quite a bit of movement, but not yanking the boot out of the binding), deflection of my vertical lever on the Fritschi was about 1/3 less than that of the Naxo NX01. Noticeable on the bench, yes. Noticeable on the ski slopes? Perhaps. Cause for concern? Depends on your style of skiing, what type of skis you use, and what type of snow you ski on.
Field testing bears this out. Expert skiers testify that while they can sometimes feel a difference between the Naxo NX01 and Freeride in terms of slop, the difference rarely, if ever, affects their skiing. With wide skis on hard snow, the difference may be noticeable. On packed powder and most natural snow (crud or powder), the difference means nearly nothing. More, if flex is a huge issue for you, consider the Dynafit, which in the same tests was more solid than any other randonnee binding.
(Caveat: An interesting thing we learned during this test was that boot movement can be significantly reduced by over-tightening the toe jaws and moving them down past manufacturer’s specified range. DO NOT DO THIS. Over-tightening the toe jaws of any Fritschi or Naxo binding model may result in catastrophic failure. Such failures have been reported with both Freeride and Naxo, and we suspect at least some of these failures may be the result of mal-adjusted bindings. More, when comparing the bindings yourself, take care that the toes are adjusted correctly. After a day of playing with these issues in the workshop, we suspect that radical differences in boot movement sometimes reported may be the result of mal-adjusted bindings during casual comparative tests in ski shops.)
And lastly, if you really do want a Naxo NX01 that’s stiffer, here is a way to modify it so it provides about the same lateral stability as a Freeride or NX21.
WildSnow.com publisher emeritus and founder Lou (Louis Dawson) has a 50+ years career in climbing, backcountry skiing and ski mountaineering. He was the first person in history to ski down all 54 Colorado 14,000-foot peaks, has authored numerous books about about backcountry skiing, and has skied from the summit of Denali in Alaska, North America’s highest mountain.