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A ski-mountaineering and speed-touring machine.

The lightweight La Sportiva Sideral Alpine Touring Boot is geared for comfort and efficiency during the ascent and hard-charging performance when you point the tips downhill. The Fast Lock System quickly switches between ski and hike modes and works with the carbon fiber exoskeleton to provide power and precision during the descent. When you're in hike mode the EZ Flex system in the tongue allows for unrestricted ankle movement, while the LazerGrip Outsole provides the grip necessary for secure travel over rock and snow.

  • The Sideral's shell is made from the ultra-lightweight nylon polymer Grilamid to reduce thickness and weight without a loss in stiffness or power
  • Nylon cuff includes an additional rear spoiler device
  • Innovative EZ Flex Tongue, made from the tough but lightweight Pebax polymer, offers unrestricted ankle movement for steep ascents and easy walking on flat ground
  • Vertebra Technology features an 'exoskeleton' that provides maximum security and precision during the descent, eliminating the need for a stiff tongue
  • 2BT Tech Last and Heel feature a minimal external volume for reduced weight and an anatomical design that excels on technical terrain
  • The thermo-moldable Skimo Liner features a double tension lace system and EZ Flex hinge for unrestricted ankle movement
  • Forward lean can be adjusted to 12, 14, or 16 degrees to match your preference and the terrain
  • Fast Lock Closure system easily switches between ski and hike modes with the spring loaded Cam Closure System and QuickBuckle
  • WarmSole innersole puts a thin, lightweight barrier between you and your cold-conducting plastic soles
  • LazerGrip Outsole features extra hard edging platforms for technical rock sections and full rubber coverage for excellent grip in mixed terrain; rockered shape facilitates a natural walking motion
  • Low-bulk heel is engineered to provide an easy fit for crampons
  • Compatible with all tech-style bindings

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Here's what others have to say...

2 5

wider then dynafit

  • Familiarity: I've put it through the wringer

I could not fit into the TLT 6, which is a much better boot in my opinion. The Scarpa Alien was also narrow and rather flimsy for any serious backcountry travels.
The Sideral fit and was light. Moderately thick liners keep feet ok warm, not toasty.
The size is small get one size larger unless you are a really good skier who enjoys pain.
My main complaint is the latch system in the heel. It is overly complicated and rather temperamental. It does not latch every time. It takes some fiddling to get it to latch. Making it useless as a racing boot or even a fast touring boot. If I am in a hurry I often just start skiing and hope that half way down the mountain the stupid thing may decide to become a ski boot rather then an expensive cold flashy Italian hiking boot.
But when it does decide to act like a ski boot it skis great.
Overall I am sort of disappointed.
Also the mid foot buckle is cheesy and will likely snap off if it is bumped against a rock. However a simple bungee would work just as well.
The boot also has a hole in the back that lets in a lot of snow and could have been better designed.
My only other complaint is about the lack of response from backcountry.com, the boots came with two right sided tilt adjustment inserts. I called them twice asking about getting a left sided one shipped out and nothing happened. Fortunately the staff at La Sportiva was responsive and promised to send out a plate. In the mean time I am learning to ski with one boot at 12 degrees and the other at 18, with random and alternating walk/ski modes engaged. But hey, think about what an awesome skier I will be when I finally get a pair of matched locking ski boots?

Responded on

so what boot did you decide to go with? I have had the same problem. Could not do a TLT6. I have a Technca Cocheise that works great for side country but I need a good not great skiing light weight AT boot that is at least 101 w.

Responded on

I eventually sent the sideral back when I noticed the lugs on the sole were crumbling off after only 2-3 months of use, ( to be fair most skimo boots do this I am told).
I find the best boot far for long tours, cold weather, and anything but technical climbing and extreme descents to be off the shelf old school Scarpa F1's.
my 4 year old pair is in better shape then my 3 month old pair of Siderals.

Is there a last-width spec available for...

Posted on

Is there a last-width spec available for this boot?

Responded on

The last width is 102mm.

Responded on

Thank you.