Overall: Five Stars for a very nicely designed ski crampon, with reinforcement ribs, a smooth retainer bar, holes nicely positioned for adding spacers, and an expanded variety of width options. Just be careful on the sizing, which can be somewhat confusing.
Background on product familiarity: Starting in the 2004-05 season, I’ve used a wide variety of Dynafit crampon widths, with a wide variety of ski binding crampon attachments, in a wide variety of conditions and terrain.
First, the first impressions out of the box: Do I really need ski crampons? Yes, you do! If the skinning might be steep and/or firm, and if you have room to set your own skintrack angle (as opposed to a below-treeline hiking trail for the ascent), then ski crampons (combined with good skinning technique) can allow you to leave the boot crampons at home for many tours, and also eliminate booting transitions. I also consider ski crampons to be mandatory for any glacier travel where your skintrack might be dictated by open crevasses or sagging snowbridges, leading to tricky maneuvers.
The Dynafit crampons are very nicely designed, with reinforcement ribs and a smooth retainer bar. Sizing though can be confusing, since sometimes Dynafit’s designed width has overstated the interior dimensions, yet ski waist widths for specific lengths can often deviate from the publicized spec that is based on a particular length.
Some more general thoughts on all of the above are at my old review here
… although for specific sizing questions, best to just ask Skimo Co!
Second impressions, in use: I’ve found that I prefer a little more crampon teeth penetration, even when used on a typical middle heel elevator or a race-style “half-step” position. Fortunately the Dynafit crampons already come with holes that are perfect for installing spacers, and the TLT Speed Nubbin is the perfect spacer, secured with hardware store fasteners (e.g., T-Nut with Brad hole 6-32 x 1 ¼ plus corresponding machine screws).
Third impressions, for long-term durability: I had previously thought that these were indestructible, and that size didn’t matter (as long as they were of course wide enough), based mainly on previously using what were probably “80” crampons on a 67mm rando race ski. Unfortunately, I then proved myself wrong, with a perfect(ly bad) combination of a 110 crampon on a 90mm ski (which I realized only afterwards actually did just barely take my 90 crampons), for skinning up a short icy slope that created lots of torque on the crampon and its binding interface. With the proverbial irresistible force up against the immovable objects of the Dynafit Vertical ST baseplate’s reinforced crampon slot and the Dynafit crampons’ reinforcement ribs, the retainer bar yielded way. Unfortunately this can’t be welded because of aluminum <> steel interface. But just keep the crampon differential well under my mistaken 20mm and you should be fine.