OAC EA Binding/USGI Karhu mounting position
OAC EA Binding/USGI Karhu mounting position
Hello, I was wondering if anyone can give me guidance on how to mount these OAC EA 2.0 Bindings to USGI Karhu skis (87-71-78) (bought from eBay). https://www.skinbased.com/product-page/ ... al-binding The bindings are similar to the Xtrace Pivot and utilizes the 75mm 3 pin mounting pattern but has no pins. I'm having trouble figuring out what reference point to use to position the binding based on http://www.telemarktalk.com/viewtopic.p ... 33200aabfa Bindings 101 info. I also read that the middle of the flex plate might be a good choice but the nature of the universal binding, the "boot center" and middle of flex plate would change depending on the person and footwear. The binding instructions manual says to follow ski manufacturer guidelines. Plans are to use these as an alternative to snowshoes for winter camping (with 30-50lb pack, no pulk), rolling terrains of the Midwest, virtually 0 ski experience. No real preference on forward or rearward biased, although if forward biased would allow me to slow down and stop more easily, then I guess I lean towards forward biased.
There are also two markings on the side of the ski, one is a circle and the other looks sorta like a Old English Thorn Þ between the balance point and CRS. I measured those out and the width at those markings ended up at 70.8mm (circle), and 70.7mm (Þ). Ski widens out to 71mm roughly at BP, CC, and CRS. Most footwear I've placed in a mock up position would have the boot center line up somewhere where this circle and Þ, whether I placed the pivot or the seam on the CC or BP (3.4cm between the two). If I use the Xtrace binding guidelines as a reference (front screw hole on CC the pivot point of the binding ends up being somewhere lined up with the circle or Þ. If i put the front screw hole on the balance point, the pivot ends up being slightly in front of the CRS. There is 8.8cm between the BP and CRS.
Appreciate any insight, thanks!
There are also two markings on the side of the ski, one is a circle and the other looks sorta like a Old English Thorn Þ between the balance point and CRS. I measured those out and the width at those markings ended up at 70.8mm (circle), and 70.7mm (Þ). Ski widens out to 71mm roughly at BP, CC, and CRS. Most footwear I've placed in a mock up position would have the boot center line up somewhere where this circle and Þ, whether I placed the pivot or the seam on the CC or BP (3.4cm between the two). If I use the Xtrace binding guidelines as a reference (front screw hole on CC the pivot point of the binding ends up being somewhere lined up with the circle or Þ. If i put the front screw hole on the balance point, the pivot ends up being slightly in front of the CRS. There is 8.8cm between the BP and CRS.
Appreciate any insight, thanks!
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Re: OAC EA Binding/USGI Karhu mounting position
Traditionally, cross country skis are mounted with the toes of the skier near the balance point. This helps with kick and glide on consolidated snow, as well as with things like side stepping.Evintos wrote: ↑Thu Dec 02, 2021 12:34 pmHello, I was wondering if anyone can give me guidance on how to mount these OAC EA 2.0 Bindings to USGI Karhu skis (87-71-78) (bought from eBay).
Plans are to use these as an alternative to snowshoes for winter camping (with 30-50lb pack, no pulk), rolling terrains of the Midwest, virtually 0 ski experience.
However, it does mean most of the weight of the skier is in the back half of the ski, so when you are breaking trail the tip of the ski will be higher up in the snow, and the tail will sink in further. Mounting at the balance point can make uphill feel steeper, and even flat can feel a little like going uphill.
If you expect to spend a lot of time breaking trail through fresh snow, you probably want the binding further forward, like the Altai Hok skishoes do. When your weight is equally distributed between the front and the back of the ski, your skis will be flatter while breaking trail, and breaking trail will be a little less effort.
Also, with the universal bindings, having the binding further forward means you'll be able to do some amount of steering your ski by nudging the skis sideways with your toes, rather than relying entirely on the rotational force transmitted through the bindings. That may be useful since those universal bindings aren't quite as good at transmitting the usual skiing forces as actual ski bindings and ski boots.
On the flip side, the distance between the balance point and the center of the running surface of your ski may take care of some of these things automatically...
Maybe mount them halfway between "boot center on balance point" and "hinge point on balance point" to get some balance between the different properties?
Re: OAC EA Binding/USGI Karhu mounting position
I mounted the bindings with the hinge point 1cm forward of the balance point (to bias the skis more towards fresh snow trail breaking) and noticed that one of the bindings was mounted farther forward than the other. I removed the bindings and checked the balance again and the balance point is correct. The result is approximately 2.54cm (1 inch) difference in mounting position between the skis. Edited to add - measured with the ski camber compressed flat.
I can't feel a difference between the two even when I swap between each foot. Each ski feeling like they have the same amount of tail drag.
Will the binding position difference be a problem?
I can't feel a difference between the two even when I swap between each foot. Each ski feeling like they have the same amount of tail drag.
Will the binding position difference be a problem?