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Skimo Co

SCARPA Alien RS Boot

$869.95 $549.95

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Every so often a company will debut a category-shattering display of engineering that seems to break all kinds of rules, defy stereotypes, and spearhead a different generation of skiing. This ain't your grandpa's ski-day! Behold: the Alien RS. Holding true to the da Vinci mantra that "simplicity is the ultimate sophistication," the Alien RS is a delightfully simple boot. A stiff carbon-infused Grilamid cuff is mated to a stiff carbon-infused Grilamid lower by way of an unbelievably dexterous pivot that again, defies stereotypes. A Boa closure on the lower shell wraps around your foot to create a secure and precise fit. Racers, say hello to your everyday boot light enough to sneak in 40,000ft of dawn patrols per week; freeriders, mountaineers, and steep skiers, say hello to your beefy race boot capable of taking you further than ever before.

  • Carbon Grilamid LFT Shell and Cuff blend industry-leading power-to-weight ratio with industry-leading price.
  • Lower Shell is built around a 3D Lambda Torsion Frame to increase lateral stability and power transfer.
  • Speed Cam Lock ski/walk mechanism is reliable, durable, and precise.
  • A waterproof, zippered gaiter tempts snow to even try to get into this boot.
  • Offset toe lugs promote a more natural walking motion to increase touring efficiency.
convert to ounces
920g [27]
983g [28]
Weight (pair) 1840g [27]
1966g [28]
Buckles   1 + BOA, Single Throw Speed Cam Lock
Boot Sole Length   270mm [24]
278mm [25]
286mm [26]
294mm [27]
302mm [28]
310mm [29]
318mm [30]
327mm [31]
Binding Compatibility   Tech only
Cuff Rotation   72°
Forward Lean(s)   7°, 9°, 11°, 13°
Specs Verified Yes
Materials   Carbon Grilamid LFT
Liner   Intuition Cross Fit Tour
Sole   Vibram UFO RS
Skimo Co Says
Usage Speed touring, high performance ski mountaineering, exceeding expectations
Notes Grilamid infused with long strands of carbon fiber increase torsional stability and precision. A zippered, waterproof gaiter invites you to use your imagination when accessing lines
Bottom Line If the Holy Grail was a ski boot
Compare to other Race Boots

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Questions & Reviews

Pete (used product regularly)
Got these at the beginning of the season and have pushed them hard, what an amazing upgrade from my old TLT 5 Ps. Scarpa seems to advertise this as a race boot, but I don't think this is the case, not quite light enough, the ankle articulation isn't quite there, and there is much too much resistance pushing the boot through the articulation for it to be called a true race boot. I think makes a good distinction by calling this category "race-plus." Boy for the weight does this boot ski, easily equal to my old TLTs, in my opinion everyone between freeride shredders and racers should be zipping around on these.

Sizing is tighter and narrower than most Scarpa boots, I'm commonly a 27-27.5, I chose a 27 in these, they fit quite nicely but it's definitely a performance fit.

Gaiter is amzingly thought out, and I love that they added a clip for binding tethers. My only complaint is that the cam device used to adjust tightness of the upper eats at the dyneema cable, hasn't failed yet, but is visually core shot. A thought as to how Scarpa could make these better is by using a full carbon upper, retaining the carbon grilamid lower and lining it with weave as in the current 1.0, this would make the boot considerably stiffer and lighter without compromising durability of the lower for scrambling. Perhaps the new 1.0 will fill the ticket.
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Mark E (used product regularly)
These Alien RS boots ski astonishingly well for as light as they are. The innovative Boa and upper cuff tightening systems provide for something that feels a bit like a four buckle design in a 2 lb boot. I have fifty days or so of skiing in these boots, and a couple days of ice climbing. No concerns or complaints about durability. Scarpa suggests that these boots are best for skis 85mm or less. I ski these on 84mm skis, but feel that they could comfortably power a bigger ski. A ski partner skis these boots on 95mm skis without complaints.

The boots are a little tight in the toe box, and fit a little bit short. I usually ski a 26.5 ("performance fit") boot, and my size 27 Alien RSs are barely big enough (I have a footbed in the boots to raise my arch and shorten my foot a bit).

Not an ideal boot for ice climbing. The offset toe welt does make the boot natural to walk in and tour in, but might require you to bend your crampons' toe bails to get a snug fit. The ski/walk mode arm interferes with the heel clip on most crampons, meaning you'll need to loosen your crampons to switch between walk/ski mode.

The boots are comfortable and dexterous enough that I have no difficulty driving my manual-transmission Subaru in the boots, and often find myself running errands in town on my way to/from skiing in the boots.

This is a perfect boot for ski mountaineering and any sort of long distance touring. If your objective is moving quickly and confidently on snow in the backcountry, I'd suggest that the Alien RS is a perfect boot.
Comment on this review:

Question from Peter D
Hi there. Was wondering if the Aliens RS can be punched. Of course Scarpa states against that and it would devoid the warranty. Currently skiing 27.5 Dynafit Beast with a small punch for my right foot bunion. Tried the Aliens RS in 28 and got a really good fit except a pressure point in the bunion. It might go with liner molding, but it did not in case of the Dynafits. I would probably need couple of millimeters punched, do you think its doable?
Thanx for advice Peter.
Answer from eric
Peter- Yes the punch would void any warranty on this boot. That said, there is some capability depending on where on the boot it needs to be modified.
Answer from Kevin Woolley
I've successfully had these punched for metatarsal region on both sides, several mm, would not hesitate to do again.
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Question from Jeff
I wear a 27.0 in the new Maestrale RS 2.0. What size would that be in the Alien RS?
Answer from jbo
Hi Jeff, SCARPA uses similar lengths across their line of boots, but the widths can vary. The Alien is noticeably narrower than the Maestrale in the same size, but about the same length.
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Question from Jim
Has anyone managed to get shorter leashes (like the Dynafit Guide) to work with this boot? I can't find any suitable locations to clip into. I realize the around-the-cuff long B&D brand ones are an option, but I'd like to use something shorter if possible.
Answer from Trace Leches
Hey James! Yeah, totally! I actually use the exact combo you're mentioning. There's a small d-ring riveted into the upper shell that you can girth hitch the steel ring from the Dynafit Guide leash into!
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Question from Erik
Can't quite get used to the 13° max forward lean on these boots. Looking at the clamp in the back for adjusting the forward lean, it looks possible to modify this to get a couple of more degrees in (drilling to offset the holes).
Any ideas if this mod has been done before?
And is it just me, or is the forward lean accually not quite normal on these boots?

Best regards!
Answer from Trace Leches
Hey Erik! Not sure if it's actually been done before but I've had this talk multiple times, including with myself. The forward lean isn't quite where I want it to be either. A less permanent (and potentially warranty voiding) solution would be to put some foam on the back of the cuff of the liner to just bump your lower leg a bit further forward. We've done that many times on these boots before to account for tiny calves or not enough forward lean.
Answer from Marc H
The forward lean is joke. I love everything else about this boot except the forward lean. The idea that less forward lean is going to keep people out of the back seat is ridiculous. Someone needs to come up with a mod and fast.
Answer from Erik K
If someone wants to know; I made a quite easy mod for this - drill two new holes to move the adjuster two notches further down than orignal adjustment range. The upper hole will only have <0,5-1 mm clerance of metal on the upper part, but dont think that is a problem. I am a big guy (190 cm, almost 90 kg), and the mod have held up nice for about 40 days of skiing (exept that the boa broke some days ago...).
Answer from Trace Leches
Hey Erik! Ha, score! That's what I like to see. Glad it's working out for you. Might do the same with mine actually.
Answer from Carbonj
Erik did you hog out the non recess area so the screw sits a little more flush?
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Question from Trevor J
Thanks for the boots. very well made and impressive in many ways :) what crampons work well with these? any crampon limitations with these boots that you've noticed?
Answer from Trace Leches
Hey Trevor! The Petzl and Camp crampons seem to work really well with the boot, but that's only if you don't plan on putting the boot into ski mode while front-pointing. If you plan on keeping the boot locked and front-pointing, use something like the Grivel SkiMatic 2.0 crampon that levers on via the toe.
Answer from Drew P
Camp XLC390 and BD Neve don't fit this boot at all, but the Grivel Skimatic fits it great!
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Question from Lars

I have the Gea RS 2.0 in size 23.0. It is quite narrow for my foot, and I have punched it twice (one time very little, the other time quite a bit). I do have aftermarket foot beds in them. How do you think an Alien RS would fit in size 24.0 compared to the Gea RS 2.0 in size 23? Perhaps the heel hold would be a problem?
Answer from eric
Lars, The first rule of boot fitting is to never go up or down a size shell to make the boot fit. Find the correct length of shell and it either fits or it does not. The Alien Rs is a much narrower boot than the Gea Rs. So if the Gea RS was to narrower than the Alien RS will be worse.
Answer from Lars B
Thanks for your answer! Do you have any suggestion on what to look for for a more wide fit in this segment?
Answer from jbo
Hi Lars, you may have a few options. Best bet is to visit our boot fitter to find out.
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Question from Troy
Does this boot actually have a zippered gaiter? I tried on a pair a couple of days ago and I didn't notice a zipper but now I am seeing a zipper in your photo and a zipper is mentioned on the Scarpa website (as well as your website). Thanks.
Answer from jbo
Hi Troy, the prototype model had a zipper but it was removed for production. Sorry we don't have an updated photo yet, but that is about all that changed.
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Question from anthony
hey, I've had about 15 days in the alien rs in a sz 28. I love them, but I got quite a bit of slop in the fit which I am fairly comfortable skiing with, however I would like to get a different liner to suck up some of the void space. I find the fit around the toes to be narrow and tight (I have a felted superfeet wool insole inside right now) but I have a large amount of heel lift and movement around the calf. I have a 2 finger shell fit at the end of the day of skiing. In conjunction with perhaps some insole shims what liner and thickness would you recommend? Without knowing much it appears like either the powertrack 10 or ultralight performance liners in 7mm may be best? As stated my biggest issues are with heel lift and space around the shin. What are your thoughts (I know its not ideal to give fit recommendations online but im quite a few states away from you guys and have bad experience with some local fitters)? As always, thanks, you guys rule!
Answer from Nate
Hi Anthony, it's a bummer to hear that you are struggling with the fit of your boots. I've fit the Powertrack 10 on a number of customers, and tried it on for my own fit. I think it will be too tight of a fit in the toes for your Alien RS. The 7mm Ultralight Performance liner will likely be too thin.

I have experimented a little bit with the Intuition Pro Tour MV liner in the Alien RS and have found that it could be a workable solution if a person is dealing with too much volume in the calf and heel. You might try that in a size 28. The other option that may work is the Palau Tour Lite Performance liner in a 28, it's a touch thinner than the Intution Pro Tour.

If you haven't already, I'd also suggest making sure you are pulling the string nice and snug before flipping the lever in to ski mode. I've noticed that getting the string tension tight helps to clamp down the lower over the instep just enough to eliminate some heel slop.
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Question from Kamil
Hey. I had a Dynafit TLT7 performance boots, but "I" destroyed them ;D I am now considering scarpa RS. The stifness is a priority, not the weight. Speed turing, all day turing, races time to time. Anyway a lot of guys told me to get new scarpas. My question is what is the sole width of these two? tlt7 performance and scarpa rs? Looking forward to hearing from you! :)
Answer from Trace Leches
Hey Kamil! Oh no, that doesn't sound good. The Alien RS sure is a stiff boot. I'd say it's about on-par with the TLT7, but the TLT7 is a bit more progressive whereas the Alien RS kind of hits a wall with the forward flex. The last width of the Alien RS is a pretty narrow 99mm and Dynafit doesn't publish any of the last info but the TLT7 is high, wide, and on the opposite end of the fit spectrum as the Alien RS. Visit our Boot Fitter Program if you'd like to proceed with a fitting.
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Question from JJMS
Quick question on sizing. I'm a pretty comfortable size 27 (a bit on the small side) in a scarpa alien 1.0 (regular non carbon). I'm hearing that the Alien RS fits a little more snug and was wondering if I should be sizing up to a 28 on the Alien RS. I know it's hard to say without seeing the shape of my foot....
Answer from jbo
Hi JJMS, in general you shouldn't have to size up (and you'd want to look at other boots before doing that). The RS liner is thicker but it also molds really well.
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Question from tryggve
hi skimo! can anyone compare skiperformance between these, fischer traverse(carbon or non carbon) and the tlt5 m? i have skied the tlt5 m(without tongue) for many long dark cold swedish and norwegan winters now,and tried the alien rs and fisher traverse on in a shop,but have a hard time leting go of the tlt5 is super old with almost no sole left and i was expecting to realy want the other boots when trying in the shop,but now im not so it realy realy such an upgrade regarding the downhill performace? i ski an old colorfull 180 vector,listening to norwegan black metal, have the same clothes for ten years so maby the tlt5 sould just stay me forever?
Answer from Trace Leches
Hey Tryggve, thanks for reaching out!

First of all, Norwegian Black Metal? How can I start listening to this? I like your style, I think new gear may cause a singularity to appear.

The Alien RS is a fantastic boot, but so is the Travers Carbon. I'd say if you're looking for a new boot in this sub-1000g range you'd be wise to start with the Alien RS based purely on fit, however Scarpa has announced that they officially only want to see the Alien RS skied on anything up to 85mm underfoot, so based on that guideline you'd likely have better success with the Travers Carbon. That being said 85mm underfoot is well within the Alien RS's limits and it's capable of driving a much, much larger ski than that. The Travers Carbon is an interesting boot that behaves fairly similarly to the Alien RS and with a bit of work you'd likely be able to get the width and volume to work for you.
Answer from tryggve
o, you just start by listening to early darkthrone, like the song snowfall or land of frost.but remember alsow listen to other music, its like skiing, only hard windpack or ice is hard for legs, at least i need to mix it up with some crust or rockskiing sometimes. so mix darkthrone with maby antony and the johnsons or aphex twin or patti smith.
i will go with alien rs when my tlt5 turn to microplastics. i think alien rs will be verry fine with skis wider than 85 mm, im light on my feet, in many ways!
thanks for your answer and happy skiing!
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Question from Fred
I fit comfortably into a 31.0 Maestrale. Any chance of fitting into a 30.0? How much shorter is it?
Answer from Trace Leches
Hey Fred! That's a super broad question to answer without knowing any finer details but the short answer is: Probably not very comfortably. The size down will be 1cm shorter internally (equates to about 1 finger thickness). If your Maestrale is a performance fit you'd have a very hard time getting the size down to work. If your Maestrale is big then there's a better chance of getting this to work.
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Question from Erik
Hello. Have these boots and used them for two tours now. Plenty stiff, would say they are very simlar to my TLT6 C One. Stiffer than Syborgs.
But - i have two questions:
1.The heel hold is not very good for my foot. Any ideas? Have a special foot bed, and a nice fitted liner. Was thinking of mounting a aftermarket heel buckle, but dont feel so good about doing modifications on a brand new boot...

2. They are a bit narrow in the mid foot area. Is this area possible to punch out easily? Have a bit of travel to get to my nearest boot fitter, so was hoping for some pointers here first..

Best regards.
Answer from Trace Leches
Hey Erik, thanks for reaching out. Glad the boots have done well for you!

1) Tough to pinpoint this issue exactly. Did these liners come from another boot? How many days do you have in the liners? L-Pads around the heel may be the only answer, but I'd only go there after a proper liner mold and then a footbed.

2) This is also a very subjective issue, especially with an aftermarket liner and footbed. If it's a thick footbed it'll lift your foot up higher into the shell and potentially make the boot a bit narrower than it actually should be.
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Question from Patrick Fink
Any thoughts on 28 vs 29 if I'm in a 28.5 F1 evo?
Answer from jbo
Hi Patrick, without knowing more I'd say a 29, which is the same internal length as your current boot.
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Question from abp
Where do you think Scarpa derived their 85mm waist cutoff recommendation? Is it because they're worried they'll start seeing failures from the torque of wider skis or do they just think it's not enough boot to push a wider ski around?
Answer from jbo
Hi abp, the new guidelines aren't specific to this boot, but rather something SCARPA is doing with all their boots to limit warranty liability. The Maestrale and F1 are now indicated to 95mm underfoot despite many skiers having already proved they are more capable than that. Maestrale RS is <=110 for what it's worth.
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Question from James Witte
Are the 28 and 29 the same shell and what is the bsl of each?
Answer from Trace Leches
Hey James, thanks for reaching out. All of this info can be found under the "Specs" tab of the product, but no, the 28 and 29 are not the same shell. The 28 is 302mm and the 29 is 310mm.
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Question from Eric S
Tried these on at my local shop, but I'm uncomfortable with their advice -- as always, shop is pushing me to get a "performance fit" -- but I want these for long distance tours, not races.

I am wondering about getting a pair of these, and sizing up 1/2 size (28 shell is about right, but slightly too small; 29 shell is about right but slightly too big). Then putting in the Proflex G liner, size 28.5.

Would that work ok? Would the liner be too high? Is this just a bad idea since I'd lose things like the little Velcro tab on the stock Alien RS liners? Any advice would be most appreciated.
Answer from jbo
Hi Eric, we've noticed some fitters confuse uphill racing with downhill racing. Depending on your shell fit, a 29 might make sense. A Proflex can take up space but it doesn't walk all that well. Something like the PowerTrack would be more appropriate in an Alien shell. Even more appropriate if you're between sizes is to check out the Fischer Travers or Dynafit TLT7 which are close in weight and articulation but sized differently.
Answer from Jan H
Hello, Eric S may I ask you please how did you solved that? did you buy a new thick liner ? didn't you try to mold/form 28 liner? and please how long is your foot exactly? my one is 275mm precisely and I have exactly the same problem. at first i bought 28, but I returnd it and changed to the 29 . but is it not good ..
thank you very much. Jan
Answer from Eric S
Hi Jan H. I didn't solve it. I found the 28 too short, 29 too wide. 28 might have worked with as toe punch, but in the end I got some TLT6s. But various things about the TLTs annoy me, and I am thinking about some of the new Arcteryx AR boots. Those fit my foot the best -- just like the TLT5s did. They might work well for you.

Can't tell you have long my foot as, because I'm traveling and don't have a good ruler handy! I will get back to you if I get a chance,
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Question from Aaron
Let's say I am a 28.5, I should be ordering up to a 29 in these correct?
Answer from Trace Leches
Hey Aaron, thanks for reaching out! Tough to say with 100% confidence about that rule, but it's definitely a safe bet. We do have an online boot fitter that might be worth checking out if you're interested in a little bit more in depth fitting info.
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Model: Alien RS

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