Skimo Co

SCARPA Alien 4.0 Boot

$2499.95 $1999.95

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Certain inventions are acknowledged as the peak of human innovation and excellence. Fire, democracy, the automobile, and now, with the addition of the SCARPA Alien 4.0, that list has grown. Coming off the legendary 3.0 platform, the Alien 4.0 has made minor improvements for those who like to go uphill fast while having a stiff and precise boot on their feet. With an updated free-floating BOA® dial taken from similar boots in their lineup (Alien 1.1, F1 LT, e.g.), one can expect slightly better fine-tuning adjustments with a quick rotation of a dial. SCARPA has also updated the 4.0 by permanently adding foam on the upper cuff for better comfort and less fiddling out of the box. Because speed can mean safety in the mountain (as well as a podium finish), SCARPA has stuck with the Speed Lock Lite ski walk lever for single motion transitions along with Spectra cord that is easy to adjust while offering a stiff ride. SCARPA has stuck with Vibram UFO rubber under your feet which equates to solid traction on a mixed bag of terrain and excellent durability. The rockered sole gives it a trail-running feel. For fast and light days where weight, skiability, and range of motion are essential - the SCARPA Alien 4.0 is now the “Ferrari” of full-carbon ski boots.

  • Full-carbon construction for the lightest boot option that SCARPA can offer.
  • Updated free-floating BOA allows for better fine-tuning and heel retention.
  • SCARPA Race 4.0 bikini liner offers a full-range ankle articulation as well as excellent thermo-moldability.
  • Vibram UFO 4.0 outsole for maximum grip and durability on varied terrain.
  • 76 degrees range of motion allows for the most efficient stride possible.
  • Speed Lock Lite System means a fast and secure single motion transition.
  • Dynafit Quick-step instep inserts are fast and reliable.
  • Made in Italy so you know it must be good.

convert to ounces
589g [41.0]
Weight (pair) 1178g
Buckles   BOA lower / Spectra cord with single throw for upper
Boot Sole Length   260mm [39]
268mm [40]
276mm [41]
284mm [42]
292mm [43]
301mm [44]
Binding Compatibility   Tech only
Cuff Rotation   76°
Forward Lean(s)   9°-13° / 11°-15°
Specs Verified Yes
Materials   Carbon fiber
Liner   Race 4.0 SL
Sole   Vibram® UFO 4.0
Skimo Co Says
Usage Racing, training, speedy touring
Notes Padding added to the cuff to lessen the fiddle factor. No metal insert in heel for extra weight savings
Bottom Line Winning races 4.0
Compare to other Race Boots

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Questions & Reviews

Question from Aaron O
For a relatively high volume foot (103mm forefoot) is this boot or the PG Pro a better option - I have tried the PG in a 26.5 and it seems like it would work, but I have heard these Scarpas (in the 4.0 version) are pretty wide foot friendly as well?
Answer from Emmett I
Hi Aaron,

I'd go with the PG, the Alien is still a narrow fit. By race boot standards the whole PG line is a bit wider.
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Question from Alex
I'm looking into the Alien 4.0 upgrading from the 3.0 which I had a size 44. I'm struggling immensely with the size charts that they provide now though, as the 44 runs in the 28 but everthing else tells me this boot should be a 28.5 but they only run full size mondo. Any help on getting the sizing being I dont have a shop here to try these on? Greatly appreciate all your insight and analyzing the crap out of this very refined gear
Answer from jbo
Hi Alex, the Euro sizing did not change in the 4.0 upgrade, so you will still be the same size 44.
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Comment from m pech
Some additional notes on this boot
1) they come with a variety of foam pieces to change the thickness of the padding that is glued to the shin-piece
2) there are two rivets located around the forefoot (visible in the photo), apparently they can be used by a bootfitter to decrease size of boot there
Reply from jbo
Hi m pech, thanks for pointing out the included foam. The rivets in the forefoot attach the BOA system, which itself is a way to change the volume of the boot. There is not much a bootfitter can do to change the carbon shell; it's more internal work with liners, shims, etc.
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Comment from m pech
With respect to the question about whether the rear tech fitting piece was made of metal or carbon fiber-- I can confirm that it is metal, but painted over to match the carbon fiber aesthetics of the rest of the boot.

Also-- compared to pierre gignoux boots-- marginally less wide in the forefoot, but tremendously better ability to handle large volumes of feet.
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Question from Anne
Hi How does the sizing in the 4.0 translate from the 1.1. If I am a 26 in the 1.1, what size would that be in the 4.0?

Answer from jbo
Hi Anne, the sizing doesn't map exactly, as one is Euro sizing and one is Mondo. You might be a 40 or 41 depending on your fit in the 1.1. Visit our boot fitter to help narrow it down!
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Question from RICHARD SAGEN
I just cracked my Alien3.0 (and my ancle) in an avalanche a week ago. Terrifying.
Are the spare parts, a whole carbon cuff available for the Alien3.0..?
My 281mm feet have more than enough space in the Alien3.0’s, do you think I would fit the new Alien4.0 in size 42?
Prepairing for NEXT season.

Answer from Will McD
Hi Richard,
Oh no! Sorry to hear about your injury! While Scarpa does send us a lot of parts, boot cuffs are not among them; you might be able to secure a replacement if you reach out to Scarpa directly. The Alien 4.0 should use the same scafo (lower shell) mold as the 3.0's so I would expect the 4.0 to feel very similar to what you're used to.
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Question from Phil
seems that the new alien 4.0 comes without metal insert on the heel for the tech binding, as shown on the pics? ture??

Answer from Teddy Young
Hey Phil, we were surprised to see those pictures as well! I appreciate you digging into the details, and it seems SCARPA has confirmed that this boot will actually have a metal rear tech fitting, so the images are unfortunately misleading. Once we have the boots in hand, we will verify specs and update this page.
Answer from Kurt P
any answers on the rear tech fitting?
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Question from mike

i am looking for a skimo race boot.
My feet lengh is something around 266mm long and the forefoot width is 103mm.

How is the fit of this scarpa alien 4.0? Is this model narrow or width in the fit?

And how is the fit in the forefoot compared to the Pierre G. /Dynafit DNA or the la sportiva stratos? And are there any alternatives too these three ultra light racing boots?

Thanks a lot!
Regards Mike
Answer from Jeff
Thanks for asking Mike. My foot is 265mm and narrower and I put the size 42 on. I have a 2 finger fit, which is a bit more than needed in a race boot. Added a footbed for fit and it feels great. There is extra room at the toe a slight heel rise that liner mold and other work could fix. With your 103mm last, it will probably be snug. Most definitely the 41 would not work. So fit on your would probably be better.
The Pierre Gignoux boots are a tad wider. The Stratos V says it has a wide 103 last, if you can find one.
Please email us for more.
Answer from Mike T
Thanks a lot for your answer!

So the scarpa alien 4.0 would be to narrow for me, and the PG or the La sportiva would work? And sry that I ask, but what do you mean with a "2 finger passform" ? And do you mean a insole with a footbed?

Regards Mike
Answer from Cole P
Hey Mike, thanks for the questions. I would say out of the boots that you listed the La Sportiva Stratos will be the narrowest out of the bunch, followed by the Alien 4.0. The Alien 4.0 is solidly in the medium to narrow category of boots. On the 2 finger fit note, in race boots we are looking for one finger able to fit behind your heel when your toes are just touching the front of the boot with no liner. For a standard touring boot with thicker liner, 2 stacked fingers behind the heel is ideal. If you have any other questions feel free to email us for more help.
Answer from Jonathan S
Agreed on the Stratos V being the narrowest of the three -- my size 27 boots fit my ~265mm C-width low-instep foot disturbingly well, like it was molded around my foot. (If La Sportiva is really claiming 103mm width, then they have to be way off!)
My Alien 3.0 sz 42 is a bit more roomy for width and much more generous in the instep.
My sz 26 RC1-generation PG has a more noticeable forefoot width flair but still fits well, especially around the instep, although part of that is b/c it's really too short for me (and fits only via shaving down all the liner toebox foam, and even then it's just barely long enough).
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Question from P Finkl
Is there any room to punch or modify the lower? or are those of us with funky feet stuck with the plasty lowers?
Answer from Zak M
Hey P Finkl, unfortunately, there isn't any modification that can be done to the carbon lower. The only modification you can get would be some room in the liner. Let us know if you have any more questions. Thanks
Answer from Anthony O
Just get gignouxs. Only full carbon that works with non alien feet. (read: average American width fit, not pointy narrow euro feet) in other words, I have to punch all my boots for width, even wide ones, and can fit in gignouxs no problem, albeit having to play with different liners
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Question from ryan ghelfi
Maybe I am missing something, but it seems weird that Scapa would only go up to a 44 for this Alien 4.0 boot. Isn't' a 44 pretty equivalent to a running shoe size of around men's 11?? There are a lot of people who basically don't have any options for a true race weight boot? Or is a 44 more similar to a 12 in a running shoe?
Answer from Jeff
Hi Ryan, Carbon boots can be tough for long or wide-footed skiers.
The 44 will roughly work for 10.5 to Maybe 11.5. And these fit towards the narrow.
Please fill out our boot finder and I will see what we can find for you. Also, include an accurate foot length to us.
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Question from Matt A
Why won't EB sell this to me right this minute? Why is he on vacation?
Answer from jbo
Hah! Good news is he is scheduled to be back before we receive them :)
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Model: Alien 4.0

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