Technical — Dynafit ZZeus Boot Construction and Performance

If you didn’t figure it out yet, we’re as excited as kids on Christmas morning when it comes to all the new Dynafit compatible “beef boots” that have risen from the horizon like a flaming sunrise after a month of storm. Today I thought it only fair to take the WildSnow microscope back to Dynafit’s ZZeus TF-X (latter standing for Thermoflex Extreme liner), which is arguably the king of such boots, since it is Dynafit’s own offering. Before you go farther, please know we’ve got a few other ZZeus reviews that compliment what you’ll see below. My firstlook is here, and check out Lee’s.

Dynafit ZZeus beef boot is an excellent offering for backcountry skiing.

Unlike my Green Machines, the color looks as good in my pickup bed as it does up in Aspen. I guess this is the “freeride” style. Fine by me, as I noticed a few rednecks frowning at my Green Machines, no doubt wondering what something of that color was doing in the back of a Chevy.

These are indeed boots with an interchangeable sole system. The touring version has a nice rubber sole and of course Dynafit binding fittings. What impresses me about the swap configuration is how precisely the sole block keys to slots molded in the boot shell. Achieving this type of precision can’t be easy. Along with an interlock, the heel portion of the sole attaches with four screws (including the screw in the actual Dynafit heel fitting).

View inside the heel block, showing binding fitting screw. One concern I have with this type of sole system is that the screws simply self-thread into the boot’s shell plastic. After a given number of repeated fasten/unfasten cycles, such thread will eventually wear and be prone to stripping. My guess is this won’t be a problem for occasional sole swapping, but do so every few days for a season and the story might be different. Thus, not a concern for most people — but keep it in mind if you plan on swapping soles frequently.

Greek gods on my feet, what has the world come to?

Except for this winter’s testing of the new AT overlaps, it’s been years since I’ve skied in such boots. But I’m not unfamiliar with the feel, since shoes such as the venerable Garmont Gara are fond memories from my day.

“Progressive flex” indeed describes it best. You press your shin forward, and instead of the bouncy energy and abrupt stop of a tongue boot such as Dynafit ZZero or Garmont Megaride, you get a sensation that’s more like you’re pressing against live muscle resistance than inert plastic. It’s a more natural feeling — and one I wish they’d work harder on building into tongue boots. Beyond feeling better, such boots can actually help you ski better by absorbing vibration more effectively and transferring leverage to your skis with smooth precision.

What’s more, properly designed overlap boots tour just as good or better then tongue boots. This includes ZZeus.

So why not just use overlap boots for backcountry skiing? Two things. Most importantly, overlap boots can be much harder to get into than tongue boots (because they don’t open with a “door” as tongue boots do). If you’re booting up indoors with warm flexible plastic, not a big deal. But try the same thing while on your back in a tent, at 3:00 A.M. during a frigid winter morning, and the story may sound more like a George Carlin excretory monologue than the mumbled pleasantries such situations should engender in gentile alpinists. Of lesser concern, overlap boots may weigh slightly more than tongue boots (due to extra layers of plastic). For those that want it or need it, the performance of overlap boots will certainly be worth these compromises. But they’re valid considerations — especially in the case of getting the boots on your feet (step one in a day of skiing?).

Back to construction details. Toe has similar features to heel, in that the interchangeable sole fits into slots with a satisfying click, then attaches with six screws.

Detail of toe sole block. The front two of six screws go through the Dynafit fitting for 100% confidence. You’d have to rip your foot of your leg before you could rip this sole off the boot.

Yeah baby, the feature every ski boot should have. Not everyone needs cuff canting, but when you do…

Lean lock is similar to other Dynafit boot models (and other brands as well). It has two locked positions, but it’s almost impossible to tell which one you’re in. Adjustable mechanisms such as that of the Scarpa Spirit are perhaps better, but add weight. We prefer having just one position and tweaking forward lean during boot fitting. Some skiers gripe that the Dynafit lean lock switch is small and hard to work with gloved hands. We never had that problem. Most importantly, this type of lock functions by having a spring loaded pin snap into a hole in a steel bar. On cold days you can get ice in this mechanism and it won’t work, ditto for dirt or sand. With some brands/models the lean mechanism is easy to remove and clean or repair. In the case of ZZeus you’d probably have to remove the boot cuff to do this. Something else to keep in mind, especially for you modders out there.

Let’s not forget underthings! ZZeus TF-X thermo liner is a beautifully constructed shoe that’s truly a work of art. If you’re prone to wearing out liners, these might change your life. They’re packed with dense foam that enhances downhill performance and resists packout. Liner is a thick wool Loden felt that doesn’t feel clammy when damp and probably wears better than thin Lycra like fabric. Outer covering is Cordura nylon that can stand up to all sorts of abuse (X in name means extremely durable). The liners even have their own lasted rubber sole. Such liners do add a few ounces to the overall boot weight, but they’re ounces with direct positive consequence (and you can always use slightly lighter aftermarket liners if desired.) Important thing about the liners (this could be pro or con) is that Dynafit says not to mold them in an oven (at home or professional), instead they need to be molded using the blower/tower system that’s become more common of late (and harder to lash up at home). The liner does come pre-molded in half-sizes, so they may fit quite a few feet directly out of the box — that’ll be nice for mail order or for getting out of the shop quickly. Downside, if you do need liner molding you’ll be dependent on a dealer or properly equipped boot fitter for the job.

What else? Mainly, know that the different colored plastic on top of the ZZeus forefoot area is actually two separately molded pieces attached by rivets. Not only does this allow for sophisticated and dare I say artistic molding, but also lets the overlap area conform nicely to your foot instead of crushing directly down as some folks experience with overlap boots.

Beyond that, everything is fairly standard for a well designed AT boot: quality buckles; nicely attached power strap; soft rubber seal at front of overlap; front buckle in a reasonably protected location. Oh, and how about weight? According to our scales, with its beefed liner the ZZeus does have some mass, but look at the weight of the shell, which is very light for this stiff an overlap boot. Thus, our point about the liner adding quality that’s worth the ounces is a good one (and with a lighter liner, you could create a lighter but still stiff boot). In all, a ZZeus TF-X is worthy choice if you’re looking for a beefy overlap boot.

(And the eternal question, will I give up my Green Machines for a pair of ZZeus? In truth, I do enjoy skiing a beef boot on occasion, but my Green Machines work fine for nearly everything I do. Much of that is simply based on style. I don’t ski as aggressively as I used to, hence a lighter boot works for me. Even so, we’re super excited about beef boots such as ZZeus because so many excellent skiers have been needing such boots for years — and we want you all to be happy out there!)

Shop for Dynafit alpine touring boots here.