Tech-Heavy Ski Boot for Mortals: Fischer RC4 PRO MV BOA Review

Few skiers besides actual racers want to spend their ski day in a true race boot. But the most aggressive expert skiers can push through the stiffest recreational ski boots. So Fischer serves up its RC4 PRO line, which comes close to the power of a plug boot in a more approachable package.

New for 2024-25, the Fischer RC4 PRO MV BOA loads a ton of tech into the build for a model that’s hard to classify but will appeal to plenty of hard-charging double-black skiers.

The carbon-infused race-grade cuff yields a 140 flex, which will be too much boot for many. But that will appease skiers who are let down by other boots that aren’t as stiff as they claim.

While it’s not Fischer’s first boot to do so, the RC4 PRO MV BOA comes stock with the normally aftermarket ZipFit liner, saving enthusiasts the hassle and cost of customizing post-purchase. There’s also a tech fitting in the toe for ski touring — but not in the heel and there’s no walk mode. More on that unique setup later.

In short: The high-end Fischer RC4 PRO MV BOA ($1,050) ski boots bring race-grade performance down a notch and pair them with a more forgiving fit for recreational hard-chargers. The BOA enclosure and wider last broaden the pool of skiers who can comfortably drive this beast of a boot. But it’s still a specialized tool for expert skiers who demand elite performance.

Read The Best Ski Boots Buyer’s Guide to see how this high-end ski boot compares to our other favorites.

Fischer RC4 PRO MV BOA Ski Boot Review

The Fischer RC4 lineup is aimed at frontside skiers and features 18 different ski boot models ranging from a beginner-oriented 85 flex all the way up to the 140 flex of the Fischer RC4 PRO MV BOA.

There are two PRO models: the RC4 PRO MV BOA that we tested here, and the LV version, which is the same on paper but with a tighter (LV: lower volume) fit. It also uses a traditional four-buckle setup instead of the forefoot BOA.

These two PRO boots gain stiffness via the carbon-fused cuff, which blends carbon into the Pebax plastic to achieve the remarkable stiffness that these boots deliver. They’re also pricey — pushing over $1,000 — thanks to high-end materials, workmanship, and add-ons such as the premium ZipFit liner.

While most casual skiers won’t want to spend over $1,000 on a ski boot, the expert skier this boot appeals to may not mind spending a few hundred extra if the $700-900 high-performance boots from other brands just aren’t cutting it.

Plus, if you’ve been eager to glitz your foot-kit with a ZipFit liner, the cost could be well worthwhile — those premium liners run around $500 a pop.

Testing Grounds

On my testing grounds in Colorado, I skied the RC4 PRO MV BOA late-season at Arapahoe Basin. I mostly wore these boots on firm early morning groomers, some delightful corn, and slush off-piste later in the day.

My local Fischer bootfitter advised against playing with the ZipFit liner in advance. So I skied it stock and likewise didn’t perform any customization on the shell, as I found the initial fit devoid of any serious hotspots.

I tested the RC4 PRO with a variety of skis and in every snow type I could find including moguls, icy hardpack, slushy groomers, and highly variable off-piste.

For me, the RC4 PRO was at its best paired with Fischer’s CURV 85 GT, a heavy frontside carver that likes to stay planted and dig trenches. The boots stayed stable in crud as well, pushing the CURV ski through side chop.

Fit: Fischer RC4 PRO MV BOA vs. LV

The RC4 PRO MV BOA has a surprisingly relaxed fit for a boot that’s theoretically just a few steps below a plug race boot.

I tested the 27.5 size, which is my normal size. While that was the right choice for me, it had noticeably more room in the toe box than the 27.5 size of the RC4 PRO LV, which I also tried on but did not ski. In fact, getting into the PRO LV was a battle at first and made slipping into the PRO MV like throwing on my house slippers in comparison.

Part of this easy entry can be chalked up to the wider 102mm last in the MV model. But the additional length is an interesting difference that I can only chalk up to a change in construction to accommodate the BOA system. This could be a good thing for skiers who find themselves between sizes.

But in reality, the MV model was likely too comfortable for me out of the box. If I skied an RC4 PRO beyond my testing period, I’d likely end up with a better fit in the LV model paired with professional bootfitter adjustments to ease the vice-like fit where needed.

ZipFit Liner: Precise Feel

The normally aftermarket ZipFit liner, like the BOA system, is third-party tech that skiers will either love or hate and could warrant a review of its own. Unlike foam-injected liners, the ZipFit has a leather shell filled with bits of cork that subtly shift during use to form around the foot.

Bootfitters that work with ZipFit can add and remove cork. But many skiers can achieve good results just ny skiing in the shelf liners. My local bootfitter suggested spending at least 7 good ski days in them before even thinking about making adjustments.

The leather shell of the ZipFit liners isn’t bulky like foam liners and pairs best with a snugly fitted shell. The heel pocket holds exceptionally well and fit me well out the gate.

Like a snowboard boot, the ZipFit has cinching laces in the front, which snug the liner up independently from the shell enclosure. This adds a step when first stepping into the boots, but does a better job than foam liners at firmly holding onto your feet and lower leg.

I found the ZipFit liners gave me a more precise feel inside the boot. For folks who like ZipFit, this will be a major plus and value-add for the RC4 PRO, since the standalone ZipFit liners cost around $500.

For those unfamiliar with ZipFit, it could be an unknown match until they try a pair on. It may give some skiers pause, since they would have to purchase a different aftermarket liner if they don’t love it. Trying the boots (or at least a ZipFit liner) before buying is highly recommended.

Downhill Performance: Stiff and Stout

Stiffness is the headline here, as the 140 claimed flex isn’t hyperbole.

I ski mostly 130 flex, a.k.a. “expert” boots, unless I’m testing softer models for review. The jump in rigidity here was immediately noticeable. Despite ambient temperatures in the 50s for some of my testing days, nothing about the carbon-reinforced cuff ever felt soft.

That said, I never felt overpowered by the boot. I was able to find my rhythm after accepting the aggressive stance it demands and consciously driving through my turns. At 6’0” tall and 190 pounds, my size plays a factor here.

Lighter skiers will likely find the stiffness to be overkill and may have to fight too much to push forward into a proper athletic skiing stance. This could be a great boot, however, for taller and heavier skiers who find most boots too soft to be responsive enough.

The RC4 PRO wouldn’t be my first choice for freeride. While the stiffness makes them responsive to quick movements at speed, they felt a tad sluggish playing around at slower speeds in mini golf terrain.

They’d be a solid choice if your off-piste skiing is mostly high-speed GS and big mountain skiing, because they like to be leaned into with steady force. I’d go for something slightly softer — likely a 120 or 130 flex option — for more playful aggressive skiing.

Touring Option

The inclusion of tech fittings in the toe is a head-scratcher at first when you see there’s no tech fitting in the heel nor a walk mode. Skimo types will think the factory made a mistake.

Truth be told, this provides an uphill option for a very small subset of backcountry skiers and situations. The 27.5 size of the boot is 2,185 g, which is too heavy to be a realistic option for anything but short missions, such as getting back to the ski lift from a sidecountry escape or speeding up a lengthy bootpack in-bounds.

But wait — can you even tour without a walk mode? Yes. And the CAST system and Marker Kingpin bindings will work with this boot and provide alpine-like binding performance out-of-bounds.

I used alpine ski boots with no walk mode in my early years of touring, paired with frame bindings, since I didn’t have the money to buy AT ski boots. It’s unfathomable for dedicated backcountry skiers who are used to lightweight articulating boots. But it’s an option with the RC4 PROs for resort-first skiers that undertake occasional big mountain lines beyond the ski area boundary.

The tech toe likely won’t be the main reason skiers buy this boot. But it also doesn’t really take anything away from it. If you never use the tech toe and only ski it in-bounds, this could still be a great ski boot for you, thanks to its many other strengths.

Plus, the GripWalk soles are a nice touch for bootpacks and ridge hikes, as well as traction around the base area and parking lot.

Critiques

Here’s the standard ski boot review caveat: Fit is obviously highly individual. The most important thing you can do to land a pair that’s perfect for you is to spend lots of quality time with an experienced bootfitter discussing your likes and dislikes, your feet, and trying on as many ski boots as you can.

I have a relatively flat, low-volume foot and prefer a suffocatingly tight fit that tends toward low-volume boots. Though, I’ve happily skied certain MV (mid-volume) models.

The BOA H+i1 system is still relatively new to the ski boot world, but it does what it claims and very evenly compresses the shell over the forefoot. Without heavy shimming underfoot, it took a tedious 35-40 twists per boot for me to achieve the snugness that I wanted. But higher-volume feet will fare better. (Shimming brought this down for me to a much more manageable 15-20 twists.)

Note that this ski boot has a customizable boot board — a removable floor that rests on the bottom of the interior lower shell and in between the boot liner — and the shell is a vacuum-fitted and heat-moldable design. That dials the initial fit in further, but only if you work with a professional bootfitter who has the proper equipment.

Fischer RC4 PRO MV BOA Ski Boots: Conclusion

At the top tier, the Fischer RC4 PRO MV BOA ski boots will appease racers and ex-racers who want a boot that gives them the rigidity and power they can’t find in other expert-oriented options.

The inclusion of the ZipFit liner and the readiness for professional bootfitting help justify the steep price tag. These boots can allow the most precise, custom fit that’s possible though some skiers may opt for the snugger-fitting LV model.

For expert skiers who like the RC4 line but aren’t sure they need a true 140 flex to have fun on the snow, consider the RC4 130, which is slightly less stiff but is plenty capable. That model comes in LV, MV (with BOA), and HV volume options.

If you’re still not sure if the Fischer RC4 PRO is your best option, check out the Best Ski Boots Buyer’s Guide for our other favorites in a wide range of styles.