NNN BC - faith somewhat shaken
Posted: Sat May 27, 2023 7:59 pm
I have been using the NNN BC boot/binding system since the early 90s and, apart from one of the original bindings (the version on which the lever was a metal ring) breaking, I have never had cause to complain. The system convinced me because of its lightness, simplicity and reliability and I currently have it on four ski-sets.
Last season (April, 2022) I had my first serious failure, when a boot sole separated from the upper in the middle of a long tour. I was lucky with the outcome, but the breakage was cause for concern (especially as the boot was relatively new) and brought me to this forum looking for a “get-you-home” solution. It was the subject of my first post on the forum. No photos could be provided, as the defective boot and its partner had to be scrapped en route:
https://www.telemarktalk.com/viewtopic. ... 256#p50256
This past season (March, 2023) I was hit again, this time by a binding failure. Again, in terms of personal safety, I was lucky with the outcome, but nonetheless had to break off the tour, fly back to Switzerland from Norway, and return later with different skis. The breakage occurred after I had left a serviced hut in the Skarvheimen mountain range, heading for a self-service hut a mere 12km to the north-east. After travelling for circa 9km my left foot suddenly came out of the binding. On inspecting the binding I was bewildered at first, then caught sight of a piece of red metal lying on the surface of the snow just behind me. The clamp “claw” which engages with the toebar on the boot had shorn off completely, rendering the binding irreparable. Luckily, the weather was stable and the very strong winds of the previous days had compacted the snow surface to such an extent that I was able to carry the skis and walk the 9km back to the serviced hut without difficulty.
On mulling over what could have caused such a breakage, I remembered that I had recently sprayed the bindings with WD-40 – using the lithium variant for the first time, instead of the standard WD-40 which I normally use. I also remembered having frost blisters from previous experiences with various aerosols in different situations, when I neglected to wear gloves. The thought occurred to me that I might have “shocked” the metal by spraying too much or too close. I then made a little non-scientific experiment by placing a thermometer on a table, on a warm late-spring afternoon, and spraying it at close range with the same lithium WD-40. The result was, as expected, a drop in temperature, but the difference was far more than I could have imagined. The thermometer happily displayed just over 28°C (82.4°F) before being assaulted by the spray but sank very rapidly to minus 25°C (minus 13°F) on being sprayed.
I have no academic background in science and can’t claim the above experiment to give a definitive result, but I can’t help thinking that the metal could have been weakened by such a rapid temperature shock. I will continue to lubricate the NNN BC bindings in future, but without spraying directly.
EDIT: I have since repeated the above experiment at ambient temperature of 27° C (80.6° F) using standard WD-40 from an aerosol can. Result: When sprayed directly on the bulb of the thermometer there was no significant drop in temperature. It seems that the propellant in the lithium WD-40 causes the deep-freezing but the standard WD-40 does not.
In fairness, it should be stated that the bindings were old. On the plastic housing inside there is a little disc which can be seen on lifting the lever. This shows the year and month of manufacture which, in this case, was March 2006. I bought and mounted the bindings about two years after that and they are on skis which have a (documented) 1500km on the clock, as well as a very considerable distance before I started documenting with GPS. I’ve certainly had my money’s worth, but, in the case of ski bindings I imagine most users would take the “If it ain’t broke, don’t fix it” attitude as opposed to “these bindings have been on the skis for xx years, so it’s time to take them off and replace with an identical pair”. The age of the binding/ski should also be seen relative to the number of skis I have (i.e. a lot!) - so some skis get used only a little or not at all during a season.
I have fortunately been spared the toebar-pulling-out-of-the-boot breakage which has been documented elsewhere, but those reports, together with the two failures described above, have somewhat shaken my faith in the NNN BC system. I consider the 75mm system, while not failure-proof, to be easier to deal with if something goes wrong, and from the conversations I’ve had with several Norwegian ski-tourists it seems I’m not alone in thinking this. I’ve become enamoured of the Rottefella 75mm with Cable, having tested it on the piste as well as on 160km of mountain touring this season, and now have it mounted on three pairs of skis. I’m aware that bails can pop off and that 75mm soles can (certainly) delaminate, but the cable/3-pin system has a certain redundancy in the design as well as being definitely superior to NNN BC in terms of purely downhill performance. Apart from the three ski-sets mentioned, I have stocked up with 75mm boots (six pairs, no less!!!). I welcome the new Xplore system, but wouldn’t seriously consider using it till it has been tried and tested over several seasons.
Last season (April, 2022) I had my first serious failure, when a boot sole separated from the upper in the middle of a long tour. I was lucky with the outcome, but the breakage was cause for concern (especially as the boot was relatively new) and brought me to this forum looking for a “get-you-home” solution. It was the subject of my first post on the forum. No photos could be provided, as the defective boot and its partner had to be scrapped en route:
https://www.telemarktalk.com/viewtopic. ... 256#p50256
This past season (March, 2023) I was hit again, this time by a binding failure. Again, in terms of personal safety, I was lucky with the outcome, but nonetheless had to break off the tour, fly back to Switzerland from Norway, and return later with different skis. The breakage occurred after I had left a serviced hut in the Skarvheimen mountain range, heading for a self-service hut a mere 12km to the north-east. After travelling for circa 9km my left foot suddenly came out of the binding. On inspecting the binding I was bewildered at first, then caught sight of a piece of red metal lying on the surface of the snow just behind me. The clamp “claw” which engages with the toebar on the boot had shorn off completely, rendering the binding irreparable. Luckily, the weather was stable and the very strong winds of the previous days had compacted the snow surface to such an extent that I was able to carry the skis and walk the 9km back to the serviced hut without difficulty.
EDIT: I have since repeated the above experiment at ambient temperature of 27° C (80.6° F) using standard WD-40 from an aerosol can. Result: When sprayed directly on the bulb of the thermometer there was no significant drop in temperature. It seems that the propellant in the lithium WD-40 causes the deep-freezing but the standard WD-40 does not.
In fairness, it should be stated that the bindings were old. On the plastic housing inside there is a little disc which can be seen on lifting the lever. This shows the year and month of manufacture which, in this case, was March 2006. I bought and mounted the bindings about two years after that and they are on skis which have a (documented) 1500km on the clock, as well as a very considerable distance before I started documenting with GPS. I’ve certainly had my money’s worth, but, in the case of ski bindings I imagine most users would take the “If it ain’t broke, don’t fix it” attitude as opposed to “these bindings have been on the skis for xx years, so it’s time to take them off and replace with an identical pair”. The age of the binding/ski should also be seen relative to the number of skis I have (i.e. a lot!) - so some skis get used only a little or not at all during a season.
I have fortunately been spared the toebar-pulling-out-of-the-boot breakage which has been documented elsewhere, but those reports, together with the two failures described above, have somewhat shaken my faith in the NNN BC system. I consider the 75mm system, while not failure-proof, to be easier to deal with if something goes wrong, and from the conversations I’ve had with several Norwegian ski-tourists it seems I’m not alone in thinking this. I’ve become enamoured of the Rottefella 75mm with Cable, having tested it on the piste as well as on 160km of mountain touring this season, and now have it mounted on three pairs of skis. I’m aware that bails can pop off and that 75mm soles can (certainly) delaminate, but the cable/3-pin system has a certain redundancy in the design as well as being definitely superior to NNN BC in terms of purely downhill performance. Apart from the three ski-sets mentioned, I have stocked up with 75mm boots (six pairs, no less!!!). I welcome the new Xplore system, but wouldn’t seriously consider using it till it has been tried and tested over several seasons.