Switch Hitting Gear – Ramp Angle & Delta

Checking boot and binding lean, delta, ramp angles.

I got an email from Darryl a few days ago, asking if I knew what might be going on with his feeling that he was “going over the bars” on his Dynafit ski touring setup, while his alpine rig felt fine. Darryl is an expert and aggressive telemarker who also switches between a full-on alpine rig and a touring setup comprising tech bindings on a pair of fairly wide all-mountain skis. Since he lives near here, I emailed back with something like ,bring over all your skis and boots, we’ll see what’s going on with that.’

While Darryl related that perhaps he needed to mount his Dynafits on his skis in a different position, I suspected we were looking at the common situation of a skier trying to switch between two very different ramp (delta) angles and boot cuff lean angles. Some skiers can do this with aplomb, while others (myself included) do better if their gear is all set to similar angles that make the switch less abrupt.

So, we flopped Darryl’s planks on the kitchen counter, snapped boots in bindings, and measured.

Using my rig of a magnetic slope meter stuck on a tri-square, it was easy to see that his ramp angle (where your foot rests in the boot) was nearly flat with his alpine setup, while it was easily 5 degrees more than that with his Garmont Megaride & Dynafit rig (much due to the built-in ramp of the Dynafit binding). More, the Megaride has two forward cuff lean settings, and we concluded it was possible Darryl had mistakenly used the more extreme choice. Adding to the difficulty of matching boot feel, the Megaride has quite a bit of arch in the shell, while Darryl’s Tecnica alpine boots have a perfectly flat boot board.

Conclusion: Darryl’s two boots had enough difference in ergonomics to make switching uncomfortable and produce his “over the bars” non-brotherly situation. Solutions: Add a bit of ramp angle to the alpine rig by posting his heel with a shim under the boot board; subtract ramp from the Megaride by adding a shim under the forefoot; get custom footbeds for both boots so the arch is the same; mark Megaride with a Sharpie to indicate correct cuff lean position while latched. Both boots don’t have to be identical in ergonomics, but getting them close should make switching rigs an exercise in brotherly love rather than internecine warfare. If not, we’ll report back. More about ramp and delta angles, including numbers.

6 Responses to “Switch Hitting Gear – Ramp Angle & Delta”

1. gn November 27th, 2007 12:36 pm

   I saw somewhere a discussion on how to lower Freerides ramp angle way back but can’t find it. My girlfriend was just complaining about how she feels its hard to get forward on her new AT setup. After placing her alpine and AT skis/boots side by side last week its obvious that the toes on the Freerides are considerably higher.

   Was there a mod to the actual toe piece or AFD itself or where people just removing that rubber/plastic “footprint” plate between the ski and binding?

2. Lou November 27th, 2007 12:51 pm

   First, remove the spacer under the toe of the binding. Be careful with screw length after doing so. See if that does the trick. Next, try a slight bit of posting under her heels inside the boots. Beyond that, people put a shim under the binding heel unit, but that’s major.

3. Jonathan S. Shefftz November 27th, 2007 2:55 pm

   Like many alpine ski racers, I have the delta zeroed out in my race setups. (Some come that way, and some need to be shimmed at the toe.) So with my Diamir setups I’m all set, but for my Dynafit setups I need to shim the toes — the extra few ounces are painful to contemplate, but the zero delta helps me with my fore-aft balance.

4. Mark McKinney January 17th, 2009 11:45 am

   First I want to say Thanks. I really appreciate your website.

   I just got my first set of Dynafit Comforts and mounted them on the exact same ski as my old Fritschi Freeride setup. The only difference being the skis I mounted the Dynafits on had predrilled holes and were mounted using the Voile adapter plate. Being it was the same ski and same boot I had skied for years, I was surprised how much more quickly my legs got sore in the new set up. I searched the internet for validation and found no similar complaints, so I lined everything up on my workbench. I wanted to see if my balance point or the ramp angle had changed. The tip of the boot in the Dynafits did move forward on the ski approximately 3cm, but I suspect the real culprit is the difference in ramp angle. I will try to adjust for it using my boot’s forward lean, but I wonder how much the ramp angle effects my fore and aft balance. If I were to try to shim the front of my Dynafit binding what would you suggest I use?

   I was also wondering if you have ever tried putting the footbed under rather than inside the thermal boot liner. I have a high arch and usually use a Superfeet footbed that seems to lift my heel out of the heel pocket of the liner. If I put the footbed under the liner wouldn’t I get a more custom fit under my foot from the moldable liner while perhaps eliminating the high heel problem?

5. rod January 14th, 2010 2:54 pm

   With the 09 Freeride bindings, i put a 5mm shim under the heel, which gave me a positive but unknown ramp angle, and I really like the way it skied.
   I am switching to hardsides and dynafit 12s, and i am wondering if i should do the same?

6. Lou Dawson 2 April 12th, 2016 6:38 am

   GN, many of the Freeride bindings can have the toe lowered a bit by removing the plate the binding toe rests on. Doing so may require shortening screws. The heel can also be raised with a shim system, but that’s quite a bit of work. Lou