Gear | Dynafit Mercury Review

Jeff Brines has spent over 40 days on the new Dynafit Mercury boot. Although not perfect for him out of the box, he’s now come up with something that skis nearly as well as his alpine boot with top notch ascending ability. Take a look for the full review…Editor’s Note: Updated 17-Jan

Update 21-Mar: Looking for a comparison between the Mercury and the Scarpa Maestrale RS? Here you go…

Update 17-Jan: I’ve received a ton of questions regarding this boot. Couple things I wanted to point out that I feel my original review failed to do. In stock trim, this boot is very, very good. The problem with reviewing boots is everyone wants something different. My perfect boot is another skier’s nightmare.  I don’t want the general market to think this boot absolutely needs modification to be “right”. For me, it did. For others, it doesn’t. End of the day its a boot that is light, stiff, allows for easy modification and will deliver performance one way or another. Take my review with a grain of salt…and remember, ski it first. THEN modify.


  • Boot: Dynafit Mercury 28.5
  • Reviewer Stats
  • Heigh: 6’2”
  • Weight: 190lbs
  • Ski: Praxis Concept, Praxis Protest
  • Binding: Dynafit Radical FT12
  • Testing Environment: Teton Pass Jackson, WY
  • “Normal” Boot: Dalbello Krypton Pro; Full Tilt Sethw/10 tongue
  • Days Tested: ~40 with approx 80K of vert


I’ll claim it. Eric Hjorliefson is the best big mountain skier in the world right now. And guess what? He does most of his skiing on Dynafit boots and bindings. Full disclosure; he’s sponsored by Dynafit (contractor for them actually) but it’s a big deal when one of the best in the business is ripping high consequence lines on tech bindings and touring boots.

Anyone serious about logging big vertical likely has been on tech binders for years. The minimalist binding weighs pounds less than the competition and works far better from a biometrics standpoint while skinning. When it comes to descending, Lou Dawon’s reports Dyanfit bindings transfers skier input to the ski with less deflection and more precision than most alpine binders. (link here)

Despite how robust the binding may be, those utilizing tech setups in a big mountain/freeskiing environment have either learned to live with some sort of a compromise when it comes to boot performance or went to great lengths to modify the boot. For example, Eric Hjorliefson’s “frankenboot” a few years back had viral-like following when the build out was disclosed to the public. (It was a cobbling of 11 different boots…)

Thankfully Dynafit took notice of Hoji’s skiing prowess and boot tinkering with offering him a contract as an athlete/contractor to help develop a line of product geared toward the modern big mountain touring skier. This season marks the first in which a product line with a heavy amount of Eric’s influence has been introduced with the top of the line Vulcan, mid line Mercury and entry level One boot models.

For the purposes of this review, we are focusing on the Mercury. For those wondering, the top shelf Vulcan is very similar in materials used, shape (identical) and function (identical). The difference being the Vulcan utilizes a carbon upper cuff compared to the Mercury’s guerilamid/fiberglass upper cuff. There are other subtle differences between the two boots we’ll get into below.

About the Reviewer:

Full disclosure. This is the first true tech setup I’ve ever been on. If you are looking for someone who can compare the Mercury to other AT offerings out there, I’m a terrible source of information. However, if you are looking for someone who is going to compare the Mercury to alpine boot performance, keep reading. We at Earlyups don’t scoff at working for our turns. That said, we’re in it for the skiing, not the climbing. So it only seems fair we really compare to the boots that allow the skier to have the most control, power and fun on the way down. This is after all billed as a big mountain/freeskiing boot…

One Choice run upon the Mercury. Teton Pass. Jackson, WY.

Furthermore, I’m a fan of 3 piece boots (Krypton/Full Tilt). They simply work better for my style of skiing. If you are a plug-boot-wearing ex racer type we may have very different thoughts on this boot. I come from a bump background. I think the McConkey turn is the coolest thing known to man. I love big skis and love throwing my skis sideways at speed.


We’re going to leave this one to the boot fitters out there. If a boot fitter says it fits your foot, go for it. If your boot fitter says it doesn’t, well maybe reconsider. Our anecdotal experience is simple. Four of us at Earlyups purchased the boot. All four, with very differing feet, have been able to make it work. Heat moldable liners, punches, grinding etc makes *just* about anything possible.

Two small things. At first the last feels much tighter than the claimed 102mm. After skiing the boot, it feels more true to 102 but still a bit smaller than listed. Second, the heal retention is very *very* good.

The rest we will leave to the real boot fitters out there.

Initial Inspection:

The Mercury features all the bells and whistles one would expect on an $800 touring boot: Dynafit’s (genius) “ultra lock” walk/ski mode system, removable tongues for better articulation while ascending, framed binding compatible soles (Duke/Guardian for example), a lace up heat moldable liner, weight around ~1600 grams etc.

For those that have been following Dynafit’s line for awhile, this boot takes more from the highly acclaimed TLT 5 line of boots than it does any other boot in Dynafit’s arsenal. In many ways, it simply looks and acts like a TLT 5 performance on steroids (and HGH with a dash of EPO).

Initial thoughts trying on the boot were as follows

  • HOLY Crap this boot is light.
  • HOLY crap this boot is stiff with tongue in.
  • HOLY crap this boot is still stiff without the tongue out.

Although it looked 3-piece like (tongue based boot) it flexed very differently than any other 3 piece boot I’d ever strapped on. With the tongue out it flexed fairly softly for the first few degrees forward then was extremely stiff in a forward flexing direction. With the tongue in it felt less soft off the top but the brick wall feeling remained. Realize however,  all this is extremely anectodatal as we all know the way a boot flexes on snow is always very different than in the showroom floor.

The rest of the initial inspection was up to par for a near top of the line touring boot. The buckles seemed well thought out, liner looked better than most stock liners and overall build quality was high.



Conditions ranged from everything the backcountry can offer. From perfect 18” of new on a soft  base to variable wind effect crusts. Most of the skiing was on “3D” snow but there were a “harder packed” run outs mixed in.
That said, if you are looking for a resort review of the boot, you won’t find it here. Keep in mind the Tetons have seen nearly 200” of snow to date. So yeah, these were “in” their element (soft snow, bigger mountains).


My first few days skiing the boot included about 2000 vertical feet of ascending per lap. I was blown away with how effortlessly the setup ascended. Again, take this with a grain of salt as I was used to an alpine boot/framed binding but this setup was mind boggling efficient and fast. I was able to consistently knock off 2k in under 40 minutes while skinning. That is notably faster for me. Subsequent ascents continued to blow me away in and around Teton Pass. I’ve logged about 80K+ (probably 20K skinning, 60K boot packing) of ascending on the setup and I have nothing but good things to say. Plenty of articulation, light, comfortable, warm (with the addition of aftermarket liner).

This boot features a removable tongue that allows the boot greater articulation while removed. I’ve ascended both with the tongue in and the tongue out. For longer descents, especially while skinning, I highly suggest one remove the tongues. For shorter “yo-yo” style laps it is not that big of a deal to leave them in so long as you are in walk mode (obviously) and leave the booster strap very loose.


Skiing & Mods:

Put simply, my initial impressions while skiing this boot was not positive. The liner hurt (despite heat molding), the flex felt awfully dead (with or without the tongue), the boot was incredibly upright and I was skiing like garbage. I played around with the boot a fair amount before modding but nothing seemed to really help. I could tell the boot would have little trouble driving a big ski at speed but it was putting me in a very unathletic position to do so. Largely due to how “brick like” the flex would become at a point and how upright the boot was “asking” me to ski.

So, I went about fixing these problems one by one. To start, I added an Intuition Powerwrap liner. For those interested in doing this, make sure your bootfitter has some way of levering your foot/liner into the shell while molding (its not easy). Adding the powerwrap and a few punches my feet felt far more comfortable and warm. Adding the liner also helped the boot feel more engaged while in ski position. The Intuition is higher and stiffer than the stock liner so this makes sense.

Second, I went about improving the flex to be more smooth and linear. One largely undisclosed difference between the Vulcan and Mercury is the inclusion of a “bump stop” in the cuff of the Mercury. What this does is allow the Mercury to flex nearly as stiff as the Vulcan with a lesser materials being used by engaging the cuff and lowers as one “unit” at a certain point in the forward flex.

Although I knew it’d make the boot softer, I removed the bump stop to allow the boot to flex naturally off the tongue as opposed to off the cuff. Essentially, I want this boot to flex like a Full Tilt or Dalbello more than I wanted the stiffest thing possible.

These changes helped markedly in achieving a more linear flexing boot (no more brick wall feeling). However, at times, my 200lbs+ (geared up) would collapse the stock tongues and I’d get a scary “folding feeling” when I most needed support out of the boot. The stock tongues are very light and made of a very stiff/hard plastic but can only support so much. Adding real booster straps helped but still, although the boot felt smooth in forward flex, (far better than with the bump stops) it was too soft for me at certain (very important) times.

So, I went about improving the tongues. I have more Dalbello parts around than most shops. Procuring a pair of stiff tongues was easy. I ground these tongues to fit the Mercury which took all of 10 minutes per tongue. These tongues  are wider, stiffer, ribbed for a more linear flex and taller.

Eureka. The boot felt supportive at speed, was no longer collapsing on me as I pushed into under heavy load, retained a smooth flex and allowed me to have the confidence I have in my alpine boot.

One glaring issue remained however, the forward lean was still too upright.

I had flipped the ultra-lock engagement to allow a few more degrees of forward lean but it was still far from enough. Hence, I added a spoiler (again off a Krypton) and padded it with a piece of boot fitting foam. This gave me the desired forward lean and support for more “back seat” landings.

NOW the boot is “done”. Is it perfect? No. I’ll keep tinkering. But I can say the boot skis nearly as well as my alpine boot with the ascending prowess of a removable tongue/light TLT5 LIKE boot.


All and all, the boot has held up fairly well so far. However, there are some rather large gouges in the lowers that have me worried considering I am yet to do any real climbing/rock scrambling. Time will tell once I go through the spring peak-bagging season. Also, as one can tell from the photos, I did have the middle buckle bail fail on me in extremely cold temps. Thankfully, procuring a robust (although not-pretty) fix was easy. For those shaking their head realize I’m extremely hard on gear. If something can break, I’ll find a way to do it. Too bad “product testing” isn’t a real job cause I’m excellent at it!

To add, the soles are wearing very well but those who are utilizing the boot on a sled have commented extreme wear in very little time. Dynafit didn’t design he sole for such puproses  so I can’t exactly knock them for it but those who sled ski beware as the sole is not replacable.

Overall I’d give the boot a “C” in durability (average).


The boot offers performance up and down that could not be found in an out of the box boot just a few years prior. For some, like myself, it may not be perfect out of the box but is easy to modify, offers a great platform for a tinkerer all at a competitive price point. The fact is I am skiing in this boot more than any other boot thus far this winter. That’s saying soemthing right there. If it wasn’t performing, I wouldn’t ski it….





          • Tim Kisieleski says


            sooooo we finally got all the mods done.. we’ve ended up using a scarpa cable set up for over the instep…. got to rock them in tuckermans Ravine (Mt Washington, Nh) yesterday….. thanks for all the idea’s … boot’s awesome…. cept the stock liner got a wrinkle so I’ve got a nice blister from the climb in…. the power wraps got ordered last night…..LOL….. you guys are a great resource



  1. Garry S. says

    So, after reading your review and your affection for Dalbellos, why not just go with the Dalbello Sherpa line? I just took out my new Sherpa 2/8s and they were fantastic. My alpine boots are older Lange World Cup 130s with Intuition liners and although not quite as stiff, the Dalbellos performed similarly and are amazingly light (and come with Intuition liners). Granted, the Dynafits are lighter but the Sherpa 5/5s are close in weight and have tech fittings. Add the booster strap and other mods you have done and the weights will be even closer in weight.

    • JeffBrinesJeffBrines says

      Love to get on the Sherpa Garry! That said, we were happy to get on the Mercury first as it is lighter and, at least shop flexing, stiffer than the Sherpa. Yes, with my mods the weight is likely similar but the Mercury made sense as a first go. Furthermore as my boot currently sits it is much stiffer than the sherpa (laterally and for/aft).

      In a perfect world I’d have perfectly setup (for my feet) pairs of Sherpas, Cochise, Vulcans, Maestrale RSs all to compare to the Mercury. Thankfully, I do have a pair of Maestrale RSs I will begin skiing shortly so at least we’ll have some comparison. We’ll keep our audience posted…

      • Garry S. says

        Thanks Jeff! Great job on a detailed and informative review. The information was especially helpful for me as a comparison as I am 5’7″ and 140# so I probably don’t put quit the same amount of flex into a boot as you do. I have a friend your size who is looking for a light AT setup that is stiff enough for big mountain lines so I will pass this on.

    • JeffBrinesJeffBrines says


      The spoiler is off a krypton pro. Drilled a small hole in the ultra lock piece (the green plastic bit the free floating cuff locks into in ski mode). Used booster strap hardware I wasn’t utilzing (on the boot). Any spoiler will work however…

  2. mike says

    For a smaller guy (145ish), do you think you could get away with the stop-removal mod using the stock tongues/liners? Or would there still be too much potential for ill-timed collapse?

    • JeffBrinesJeffBrines says

      Absolutely. Realize all the prototype testing was sans bump stop and many commented the boot was still “too stiff”. I think you’d be fine taking it away without risking a “collapse”.

  3. Justin says

    What are your thoughts on the removable tongue? Do you find it to be a pain in the ass, putting it back in at the top, when its cold, windy, not on flat terrain? What about the Ultralock (or whatever its called) buckle not having any micro adjust, do you miss it?

    • JeffBrinesJeffBrines says


      The removable tongue doesn’t bother me too much, it takes no time at all to put in/remove. If it is a huge pain in the ass for some reason (weather for instance), its not impossible to ski the boot sans tongue. Especially with the bump stop intact. That said, I’m not exactly known form my ski-mo like transitions either so take it with a grain of salt.

      As far as the buckle not having micro adjust, this doesn’t bother me at all. Totally a non issue in my experience.

      Hope that helps!


  4. GDreej says

    I just picked up the Mercury, and you’re bang on with your thoughts on flex and forward lean. Jeff, have you ever ran into the boot being too soft since you’ve modded it? I’d like to try it, but I’m afraid to grind the bump stops out to only rely on the krypton tongue and find it too soft.

    • JeffBrinesJeffBrines says


      Sorry for the late reply. I haven’t found it too soft with the Krypton tongue (vertically). Only place I feel the boot is sometimes too soft is laterally (should have gone with the Vulcan!). But remember, I’m big, and LOVE to throw my skis sideways.

      Although I’m not 100% sure, I feel pretty strongly you could add the bump stop back in (even in a different spot) utilizing a piece of plastic and a few rivets/nuts/bolts whatever. All you need is something to contact the lowers and keep the boot from flexing. Plenty of ways to do that.

      Hope that helps. Best of luck and keep us posted how the boot is for you.


      • GDreej says

        Jeff, I’m also a bigger dude digging the smear-to-whiteroom style. I ended up grinding out the stops on my pair, tossing a WC Booster strap, and sanding some Krypton B tongues to fit. I spent a day riding around the resort in soft chop, but I’ll need to do some serious boot fitting before I get an accurate feel of the flex. There is some serious foot pain on my forefoot/instep, it seems to be the nub that holds the stock tongues in place pushed down from the Krypton tongue. It looks like it would almost fit between the ribs, but I doubt it considering the pain. Did you grind those out on your boots?

      • gdreej says

        I wish I could say I’m in love with this boot as much as you, but I can’t…yet. Since you’d broken your middle buckle too, was it due to the Kryp tongue having too tight of fit? I’m not sure whether the new tongue is being clamped down properly by the middle buckle, which makes me want to put a Krypton/Full Tilt cable on to sit properly between the ribs. I’m really wondering how I’d do this, considering the FT/Kryptons have the notch molded into the lowers, behind the cuff. If if figure this out, I’ll send a pic over.

        My ankle seems to be swimming around, and as you’ve said above, you have friends with all different foot shapes happy with this boot, so back to the boot bench for me. Frustrating. Perfection with this boot will be worth the time I have (and still need) to put in.

        • JeffBrinesJeffBrines says


          I actually broke the cable with the stock tongue in in absolutely frigid temps (-15Fish?)

          That said, interestingly enough the TLT6 next year has the steel cables stock (a much more aesthetic version of what I replaced with) Getting the cable to properly sit on the tongue would probably help some but I am guessing that’s not the issue (so long as you aren’t bottoming out the heel retention bail while buckeling).

          Perhaps some foam on your liner around the heel in the right spot might help? There are a thousand ways to add boot fitter foam to help heel hold if the area has too much volume. Try that to take up volume…

          What liner?

          • GDreej says

            Hey Tim, I’m interested to hear how you retrofitted the Scarpa instep cable, or see a picture of your mod. I’m thinking of shortening the middle buckle ladder band and moving it completely off the tongue, so only the cable would be sitting on the tongue, like a Full Tilt. Maybe I’ll mod a FT tongue to fit on the Merc.

          • Tim Kisieleski says

            let me take a look tonight.. I’m pretty sure that at the end of the day I just redrilled the buckle tab further out… I’ll take a few pictures

  5. Dan says

    Do you think it would be possible to put a full tilt tongue in this boot? it would likely require a lot of modification and could compromise the goodness of the full tilt tongue. I’d like to hear your thoughts.

    • JeffBrinesJeffBrines says

      I absolutely think its possible. I only went Dalbello because A) I had them laying around and B) I believe the “Stiff” Dalbello is marginally stiffer which suits this boot well. With a dremel and or bench grinder anything is possible. I say you give it a try!

  6. SonDan says

    Great review Jeff. The only mod i haven´t done that you have is the removal of the bumpstops. I am seriously considering removing them, however i fear the boots might get slightly too soft. What letter (stiffness) did the krypton-tongue you used have? i unserstand B and C is the normal ones with A the stiffest and D the softest option. Compared to your fulltilts, what flex-index tongue do you think the fully modified mercurys could be compared to? Thanx for all answers!

    • JeffBrinesJeffBrines says

      I’m in the “B” tongues. I’d put it somewhere around an 8 flex of a Full Tilt. But its hard to say as the boot is softer laterally than a Full Tilt. Also, don’t forget, if you pull the bump stops and want to put them back in its as easy as adding a bolt/not to that area. (Nut contacts the lowers just as the bump stop would)

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