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Ski Boot Binding Ramp and Delta Angles!

By Lou Dawson | December 7, 2016  

Update: We’ve found that many skiers think bindings have one ramp or delta angle that can be expressed in degrees. In other words, we hear people asking things like “what is the ramp angle of that binding, 12 degrees?” One of the most important concepts in ski binding ergonomics is this: If your boot and your foot inside the boot are not at a somewhat level position while in the binding, you do have a binding “ramp” or “delta” angle. ONLY… THIS ANGLE CHANGES AS YOUR BOOT GETS LONGER OR SHORTER.

Now, before we are excoriated by marketing people who like to spout off with binding ramp angles, we’d guess that when you do hear things like “that binding has an 8 degree ramp,” that’s probably measured with the standard industry size sample boot, generally a size 27.

Main takeaway, beyond basic like or dislike of steeper binding ramp angles, many touring bindings do have significant ramp and skiers with shorter feet may experience incredibly exaggerated forward (heel higher) ramp. Solution is to be aware of what you’re buying (use the chart below), but also know that it’s quite easy to shim up the toe of most tech bindings using various sorts of DIY or aftermarket parts.

Also updated, spreadsheet below has some angles calculated using different boot lengths. Note those angles were calculated after adding 2 millimeters to the boot heel height to compensate for the position of the tech fittings in most boots. I also added a Fritschi Freeride frame binding for reference, with inserted boot still measured to the centers of the tech binding fittings.


Spreadsheet above, ski binding delta (ramp) numbers. Note, we’re trying to adhere to a convention here in calling the binding angle “delta” and the angle created by the inside of the ski boot we will call the “ramp.” We are gradually editing past articles to that effect. If we’re talking about the combined delta and ramp angles, we’ll probably call it “combined ramp angle.”

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G3 ION LT Ski Touring Binding — Long Term Review

By Louie Dawson | December 6, 2016  
The G3 ION bindings lost in the carbon sea of the Spoons.

G3 ION Lt bindings lost in the carbon sea of DPS Spoons.

G3 has done an excellent job with the ION binding. The design is fairly standard, as far as tech bindings go. However, it’s well thought out, and has some key improvements. It is also well made; all parts are what appears to be reinforced plastic or metal.

I’ve been using the LT since last winter, on a variety of skis. I mounted them on the mega fat DPS Spoon skis. I intended to only use the setup in powder, but ended up skiing them on the occasional icy resort day — not my favorite thing but a good test. Icy conditions, wide skis, and tech bindings set to “normal” release values can be a bad combination. I was cautious initially, but eventually grew confident in the binding’s ability to hold me in. I haven’t pre-released yet in the IONs. Apparently the geometry of the toe unit as well as adequate toe wing pressure make a difference.

Added value re the toe unit performance: Many people find they can tour some distance without locking the toes. That’s nice when you forget to lock, and can be beneficial when tiptoeing through avalanche terrain.

(See our research on tech binding toe wings.)

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Mammut Ultralight 20 RAS Avalanche Airbag Backpack Review

By Lou Dawson 2 | December 5, 2016  

(Please note, regarding our use of the Mammut carbon cylinder that’s only retail available in Europe. Quite a few of our readers are in Europe, and the cylinders can be brought to North America from Europe on direct flights. So we chose to configure these packs with the lightest weight option possible.)

The object at hand.

The object at hand, Mammut Ultralight 20 super minimalist airbag backpack. 2-way radio for scale, I carry it in the vest pocket of my layers. Black object on shoulder strap is a camera bag.

Weight 1592 grams with carbon cylinder. Airbag backpack. Need I say more? Sure, it’s a blog, more shall be said.

Ever since Mike Arnold did our initial testing of the Mammut Ultralight 20 RAS (Removable Airbag System) I’ve been eager to configure one of these rigs for my own real-world use. I’m a “normal” user of this sort of rucksack, since my tours are generally more moderate than Mike’s, and I don’t do as much hardcore ski mountaineering as I used to. Well, I got it done — I’ve been out with the little blue fellow for a few days of powder skiing in Colorado avalanche terrain.

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OLDER POSTS »

  Your Comments

  • Bryan: I bought and skied these bindings the first year they were released. Great ...
  • Lou Dawson 2: Rom, I fooled around with this and it seems I'm always going back to just t...
  • Rom: If you hold your pole with your hand forward of the heal unit, and give the...
  • Witold: Hi Joseph, What type of modifications to Arva Ultra shovel? What is the we...
  • Jeremy C: @Joseph, many thanks. I would have guess Arva, and their Skimo style produ...
  • Bill B: Hey Lou Thanks for trying to explain all this. We get a lot of people wa...
  • Lou Dawson 2: CN, please leave comments on the post they refer to. Thanks, Lou https:/...
  • Lou Dawson 2: Lee, Louie is untethered at this time, I can say that all of us in the clan...
  • Lou Dawson 2: JC, see this blog post and remember that ramp angle is dependent on boot so...
  • Lou Dawson 2: Ok Lee, point taken. The reality is there is no need to discharge the c...
  • Nathan: My standard uphill load with the Mammut Ultralight RAS 3.0 is weighing 3640...
  • Lee: Lou, I know you have a wide European readership. Yes it can be transported...
  • Lee: Are you running the BnD leashes or going naked?...
  • cn: How does the Dynafit Radical toe fit into that comparison chart? Is it tigh...
  • Joseph: @Jeremy C Poles are BD carbon FLZ with modification to fit powderbasket (3...
  • Derek: How does the mounting pattern stack up to a '15/'16 Kingpin? Looking to re...
  • Jeremy C: @Joseph, any chance of a brand name kit list? Going on basic weights a sho...
  • Maciej: After 10 days on snow I love F1 Evo for the way they work and fit. The onl...
  • Joseph: That's including foldable poles now that I think about it. I never carry wa...
  • atfred: Damn, Joseph, even with some water, your airbag pack load would still proba...
  • Jonny: Hi, guys! Great job done with this article, thanks! Just one question: Do ...
  • JC: Any exact figures on the ramp angle? Much less than the Ion 12?...
  • Joe Stock: Well then we should ski together sometime Rick! I look forward to meeting y...
  • Rick: Joe, I've been skiing South Central for 35 years and definitely do not *f...
  • Scott: Sorry to admit it Lou; but the Ion is the binding Dynafit should have made!...
  • david: MarkL - thanks for the "late" response - the email alert is cool as not eve...
  • Chris: Like Lou, I discovered after a while that getting creative with small space...
  • NT: Just got my wife the ion 12's with brakes. She's able to go from tour to sk...
  • cam: http://us-store.genuineguidegear.com/products/g3-ion-ski-crampons new cr...
  • eggbert: Well, I guess job security isn't something you'll have to worry about Lou. ...

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Welcome to Louis (Lou) Dawson's backcountry skiing information & opinion website. Lou's passion for the past 50 years has been alpinism, climbing, mountaineering and skiing -- along with all manner of outdoor recreation. He has authored numerous books and articles about ski touring and is well known as the first person to ski down all 54 of Colorado's 14,000-foot peaks, otherwise known as the Fourteeners! Books and free ski touring news and information here.

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Backcountry skiing is dangerous. You may be killed or severely injured if you do any form of ski mountaineering, skimo randonnee and randonnée skiing. The information and news on this website is intended only as general information. While the authors and editors of the information on this website make every effort to present useful information about ski mountaineering, due to human error the information, text and images contained within this website may be inaccurate, false, or out-of-date. By using, reading or viewing the information provided on this website, you agree to absolve the owners of Wild Snow as well as content contributors of any liability for injuries or losses incurred while using such information. Furthermore, you agree to use any of this website's information, maps, photos, or binding mounting instructions templates at your own risk, and waive Wild Snow owners and contributors of liability for use of said items for ski touring or any other use.

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