The Phantom Slipper HD Hard Boot

Price

$829.95 (2021-22)

Gender

Not specified, probably anyone so long as you fit the sizes on offer.

Brand // Manufacturers

What we liked …

Really surprising comfort; Buckles with fixed increments for easy on-the-go adjustment of boot tightness; Buckle adjustment ability; Forward lean adjustment options; A hard-boot that’s not super-hard, still retains some flex for a more surfy ride; Hard-boot benefits for touring on icy traverses and kicking steps.

What we didn’t …

Wear and tear issues after just one week; Price (before imput duties!)

The Verdict…

THE SHORT READ…

Like any hard-boot, it makes things like touring on icy or hard-packed traverses and kicking steps much, much easier and more comfortable. Additionally, though, the Slipper HD shines in having some shell flex and providing the unique sprung ‘link lever’ to control forward lean, both of which mean the Slipper has that surfy riding feel we all want on a board. Loads of adjustability both on the hill and back at the lodge. They are not perfect however, these great pros do come with some cons that aren’t entirely minor – mainly price and wear-and-tear concerns. Read on!

And if you want to read about the range of hard-boot kit on offer, you can check out our “Going Hard” article, here.

As of September 2024 Phantom have stopped production of the slipper, they will continue to support clients with spares, and they’ve a few left on their site to buy, so you best be quick!

THE LONG READ …

The Slipper HD is the “Heavy Duty” version of the original Phantom Slipper splitboarding hard-boot. It comes with a taller gaiter (an internal sleeve to help prevent snow ingress to the inner) and a removable plastic tongue to protect the upper’s otherwise-exposed lower gaiter material and stiffen the whole thing up while riding and touring.

I bought a pair and used them for about a month this last season, in a range of conditions – from spring snow in January to an arctic hurricane - and in a range of riding and touring styles – from pure piste-bashing to technical high-alpine touring – so can share with you a decent set of first-impressions about them.

The Build

These boots are an adaption of an Atomic ski-touring boot rather than a ground-up split-boarding boot. The adaption has clearly been done with quality in mind, though overall the boot still a has bit of a ‘modded’ feel about it.

One Phantom change is the relocation of the original over-foot strap – it’s original attachment location still visible, moulded into the shell – has been changed for a pivot buckle that attaches to the upper cuff pivot points, to give more ankle lock.

A rear ‘link lever’, another Phantom addition - see the pic below - controls the forward flex behaviour, and is really a thing of beauty. Precision engineering that looks like it could have been part of the original boot, and which for me has a kind of steam-punk feel to it, due to the wire-like springs that project out the side of it and help snap it into up into it’s touring position and down again for riding.

Rear-view showing the sprung “Link Lever” to give a surfy, progressive feel.

While they look very skinny and streamlined, they are actually a very similar weight to my Northwave Domains – both Mondo 29s, and including their insoles and liners:

Northwave Domains: 1169g per boot
Slipper HD: 1327g per boot (so about 150g-odd more)

And just in case you were wondering, I weighed the rest of the binding kit too, for each boot – including heel risers, pucks, toe tech, the works, required to tour for each boot, and found this:

Spark touring kit (Large): 911g per ski
Phantom touring kit (Large): 894g per ski (so about 17g less)

For me then, the full Phantom boot and binding set up ends up being about 130g heavier per leg than my soft-boot set up, so 260g heavier in total.

Sizing, Fit and Comfort

There are only four sizes: Mondo 26 (UK 7-7.5), 27 (UK 8-9), 28 (UK 9.5-10) and 29 (phew, I just squeak in: UK 10.5-11).

Out of the box, it’s a narrow-foot fit. I’ve very narrow feet myself but still felt the need to pack out the inners around the side of my toes with a bit of DIY heat-moulding in the oven. After a month of riding, I still have the feeling that one day I might want to blow the shell out fractionally either side of my toes to let them spread a little more, but I’ll see how the inners pack down over more time first.

I’ve quite low arches and found that there was a bit too much space over the toes, arch and ankle. This was easily solved by replacing the standard boot insole with my own custom ones (slightly trimmed in width to fit), and by putting in the additional half-height insoles that also come with the boots. Nice and snug now.

Great adjustability - The entire buckle assembly on the pivot (ankle) strap has a couple of different positions you can move it to, and that, together with the 4 latch positions in the buckle give a lot of adjustability for ankle sizes and preferred heel-lock pressures. The upper cuff buckle has similar adjustability.

Notice in the pic below how the back of the shell though is more than an inch higher than the top of the Spark binding back-plate. I reckon that must translate into more control on heelside turns. The inner itself is also taller than softs, not that I noticed that when they are on.

Check out the overall reduction in ‘fatness’ with the Phantom compared to my softs, in the pic above. I’m not trying to pick on Northwave here, it would be the same with most, if not all soft boots.

Was that slimness going to affect warmth? I rode these Slipper HDs in negative-15C or so temps and didn’t get cold, so maybe no issue with lack of fatness there.

Alright, alright, what about actual comfort while wearing them? Well, I’ve been frankly astonished. 30 days in them, without the benefit of a custom/professional fitting, and – not – one – single – blister. Ok, I might have been lucky with my foot shape, nothing too irregular about them. But really, I’m still amazed. Yes, there have been some pressure points I’ve felt at times, but that’s all been adjustable and dealt with using different buckle and latch positions, whether walking or riding. I love them. That old adage about the best thing about snowboarding being the soft boots for après-ski comfort? Not sure that holds water (or beer) any more. I wore these dancing, no problem. In fact, the range of forward lean possible by having a proper ankle pivot, means that these are not just as comfortable as softs, but more comfortable in certain situations – i.e. at the bar, and while touring – less resistance in the forward lean.

Walking & Touring

Engaging walk mode – Just flip the link-lever up at the back. There’s no dangling cord or attachment on the lever to help you do this, you need to kind of get your fingers between the lever and the back of the boot, which can be tricky in fat gloves, and I find I sometimes have to try applying a bit more forward or rear leg lean, plus working with the fingers, to get the lever to disengage and flip up. But so far, no major hassle. And having a proper walk mode is a big energy-saver - immediately you’ll feel less stride resistance.

Edge-hold - Right, so the main reason I wanted to try out hard-boots was for traversing of hard-packed and icier slopes. I can’t say here whether the Slipper HD is better than other hard-boots at this, but I can say they rock when compared to all other soft-boots I’ve ever used. So much more ability to get an edge – most noticeable with the downhill ski - to engage and hold in the slope. Game-changing. Much more relaxing on a technical traverse.

Even so, it’s not that the HD is super rigid side-ways or laterally. I need to break that statement down into two parts:

As far as I can tell, from the ankle pivot upwards, it can be very stiff laterally, if you want that, depending how tight you do up the upper-cuff buckle.
But in the lower part of the boot, there is some torsional twist when you put an edge in. Look closely at the boots - see the pics below - and you can see the torsion happening - the boot bulges out sideways a bit where the curved inner-shell edge meets the very front of the gaiter. The message here is that yes, they are hard-boots, with the big boost in edge-hold ability you get with that, but they still have some flex. Enough that I almost think of these as ‘semi-hard’ boots. And even this is tuneable - the shots below were taken when the removable tongue was out - if you use the provided plastic tongue (recommended, as you’ll read later) this will reduce that torsion somewhat and stiffen up the torsional flex.

Boot-pack step-kicking – Another general benefit of hard-boots, not just the Slipper HD. But yep, so much better than with softs. The general narrower shape of the boot than with softs means you can generally make a deeper step for the same kick-force applied, and the hard sole makes holding that perch easier.

Fixed buckle positions – I’ve still not settled on the ideal pivot and upper-cuff buckle positions for walking, got some more experimenting to do. The great thing about fixed buckle positions is you can memorise exactly what position you tried, or like and just go straight back to that or try the next position, unlike with a velcro strap or cord that is effectively infinitely adjustable but where you might never quite be able to replicate the same position you like next time.

Range of forward lean / stride-length – Yeah, you really notice this compared to softs, with a genuine ankle pivot – maybe not more of a range but less resistance as you stride – smooth and energy-saving. You especially notice this when you don’t use the HD’s provided plastic tongues – you can take real long strides. But, for wear-and-tear reasons you’ll read about soon, the recommendation is to use those tongues. Once those tongues are in, you do lose a bit of range of movement but still it's improvement over softs.

Width – Although the shell of the boot is way less fat than with softs, the width of the boot at the ankle pivot isn’t too far off the max width, including the bindings as shown here, of my soft set-up. But, it is narrower. Maybe by 1.5-2cm per boot.

What I felt that translated to was needing to walk slightly less like a Texan when touring. I could narrow my stance slightly, with less chance of banging the set-up together at the ankles when one leg is brought past the other. It felt more energy-efficient. Now, the only thing driving my touring stance was the width of the board halves themselves.

Riding

Engaging ride-mode – A new thing to remember to do and I did forget a few times. In soft snow it took me a while to realise! It’s easier than engaging walk-mode, just flip the rear link-lever down, adjust your forward lean till you find the point the levers’ tooth engages with the pin in the boot and give it a gentle tap to fully engage it. There is no ‘lock’ to engage, it’s just a friction thing and once in position it stays there. Also, don’t forget to do your pivot and upper-cuff buckles back up!

Ride feel – The key thing, eh? Some qualifiers first - I’m the first to admit that I’m no pro rider with the uber-sensitivity to differences in kit you’d need to make a living out of riding. Also, I don’t ride park with all the flex you’d want in a boot for that.

Taking that into account, for the types of riding I do, which is mainly touring in all sorts of terrains, big-mountain, off-piste, piste and the occasional attempt at a 180, these feel almost as surfy to me as any of my softs. I think it comes down to the adjustability of the buckles, and the inherent flex the lower part of the boot shell has.

I’ve read other reviews saying the ride felt “mechanical”, but I just didn’t get that. You do need to play with the buckle adjustments till you find your sweet-spot settings, but even as I type this I’m thinking back to a big, wide, high-walled natural halfpipe in the Swedish backcountry, slashing up and down that, or banging out quick and precise turns to get around rocky islands in a couloir, or trying little playful airs off the edge of a piste, and never once feeling held-back by these boots, or my riding joy restricted because of them.

[Added Oct 2022] Those tongues - good for boot protection but do stiffen things up noticeably. However, when contacted about this, Phantom acknowledged that some riders prefer to keep the tongues but get some flex back, and to do that they recommend a mod - make a cut in the tongue at the sides of the bend, as shown below. In this set, sent by Phantom, they seem to have melted it rather than cut it. It would need to be wide enough to allow the upper part to clear the lower part when the tongue flexes backwards - check it out - it’ll be interesting to see what happens with the remaining plastic between the top of the two cuts, over time:

Phantom’s link-lever needs a mention here – on the original boot it’s solid, but Phantom have engineered a gorgeous sprung version, to give you progressive resistance in your forward lean and a much more surfy feel. I love how steampunk it looks.

It all looks pretty bomber too, with the possible exception of the little springs at the top, which are there to help spring the entire lever up in tour mode and back down into ride mode. But after 30 days riding so far, they are still looking in good shapre - the worst that’s happenened is they collect a the odd thread from the fraying bottom cuffs of my ski pants.

It all works, for sure. And you can swap out the springs too, for ones with different ‘spring rates’, from Stiff to Super Soft, in different colours, your choice, based on your weight range but also your ride-feel preference. I’ve been running with mid-stiff, not tried other springs yet.

One caveat here - it may not be only the spring that sets the end of your forward lean range - the ankle strap can get in the way before the spring maxes out. See the effects of this in the Wear & Tear section…

Other Features

Toe tech inserts – Industry-standard to fits any manufacturers toe tech gear.
Crampon suitability – front and rear ‘ledges’ for automatic crampons – but I used good old-fashioned ‘universal’ style that can literally fit any type of boot, and which I also use with my softs.
Rubberised sole – The out-sole seems to have great grip on rocks.
Liner – Atomic’s own “Platinum light” liner – feels stiff and not super ‘plush’ in the hand, but for me, when on the feet, they delivered comfort and warmth - and I didn’t over-heat on hotter spring days.
Gaiter – The same toughened cloth material over the top of the foot extends upwards toward the top of the cuff to stop snow ingress between the shell and liner. You have to find your own technique for setting the upper part of the gaiter in place before then doing the upper cuff buckle up. There is magnet in each of the gaiters two upper corners, but the magnet is not strong I’m not sure they snap very well onto with the matching ones in the liner.
Removeable Plastic tongue – These are provided with the HD ostensibly to give another option for firming up the forward lean resistance when riding, and for protecting the exposed gaiter material over the top of the foot. They do actually do that, for sure. The downside being a reduction in forward lean range and more stiffness, such that you need to rethink your buckle settings to loosen things up a bit more again. Check out the ‘Wear & Tear section’ for more on these.
- Note that Phantom recognise the over-stiffness the tongues can lead to and do offer a tip (if you write to them) on how to mod the tongues to get a bit of the flexibility back – basically by cutting slots in their slides, at the bend, to allow them to flex forward more easily. I’ll be testing that out next season and provide some pics here of that.

Wear & Tear

Amazingly, it didn’t take long to notice some significant wear. My very first few days out in them, I chose to ride without the tongues to see how that felt. When I eventually paid close attention to the area around and under the pivot straps I got a bit of a shock:

The pivot buckle had cut into the top of the shell

Pivot buckles own rubberised sheath worn through

When leaning forward when riding, with the pivot buckle done up to lock the heel in, the upper cuff was then hitting the pivot buckle near the end of the forward lean range and forcing the pivot buckle assembly into the shell above the foot. The damage was three-fold - per the pics above:

The gaiter material over the top of the foot was rubbed to the point holes developed in it.
The edge of the shell where it meets the gaiter over the top of the foot was cut into.
The rubber coating over the pivot buckle straps was worn through.

I spoke to Phantom about this immediately and was told they knew about this issue but that it’s “not reported by every rider”. Some riders go without the tongues (and the original Slipper doesn’t use tongues) and somehow they don’t get this problem… I can’t figure out how that can be, but there you go. I was one of the riders who did have the issue. Phantom said that using the tongues will prevent this damage but that, yes, it had the “downside” of stiffening the boots more - though the Phantom-recommended mod to the tongues to return a bit more flex will help here (see earlier).

It's true, they do stiffen the boots noticeably, but the buckle adjustability still let me find settings that kept my ankle reasonably locked and let the upper cuff move pretty well, keeping the surfy feel.

But, even with tongues in, only the first two problems above are solved - with them in, the upper cuff still hits the pivot straps and although the pivot straps now can’t damage the top of the boot anymore, the rubber protection on the pivot straps themselves is still getting damaged and at some point, I’m going to need to do something about that, as I guess the cuffs will start wearing the actual webbed strap itself away, now it’s rubber protection is gone.

Certainly from my email exchanges and photos sent, this wasn’t something triggering any warranty process. I’m not sure a replacement pair of boots would solve any problems – it seems an aspect of the design that only affects certain riders, apparently, based perhaps on how tight they need the pivot strap and their stride-length. I can only think that I experienced then because I’ve got skinny ankles and need a tighter pivot strap to get the heel hold, and because I’ve long legs and have a long stride length. Maybe.

Phantom’s choice to move the foot buckle from the original position moulded into the boot, to the ankle pivot, does allow more heel lock but at the expense of forward lean range (and maybe longevity, certainly for the pivot straps).

Overall

On the upside:

General comfort is fantastic, whether riding or touring
Temperature-regulation was great, no complaints in spring heat and arctic cold
All the hardboot benefits are there, for kicking steps & side-hilling
Adjustability is fantastic
The rear link-lever is a wonder of engineering that does deliver a surfy progression in forward lean to the boot and makes transition from walk to ride and back easy and reliable.
Riding in them was a joy (despite the points coming up below)
They are the the only ‘affordable’ splitboard-specific hard-boot in a 290-295 mondo.

On the downside:

Wear and tear – With tongues either in, or out, there seems to be challenges here with the upper hitting the ankel strap and wearing away it’s protective sheath, and then the strap itself.
Pricey - And you still need to pay import duties on top, for anywhere outside the US.

All things considered I am stoked to think about riding the Slipper HDs again this coming season. I’m biased, of course, being committed, having actually bought them, and if I was coming at this decision fresh, I’d certainly have a lot ot think about before making my choice. I hope this review helps you if you thinking about making the move to hard-booting!

For now, your other options are the Key-Equipment Disruptive, about which Backdrop’s Pete has written his first impressions of here, or using a ski-touring boot (you can check out some more about that in our “Going hard” article about hardboot gear options.

Words and most photos - Andy Beale. Other photos courtesy of Phantom.