La Sportiva Sideral: numbers and rationale

First, the numbers: in mondo 28 the shells weigh 37 ounces (each, w/o footbed or powerstrap), the liners 6.7 ounces. Not too bad when you consider my size 46 BCX11 pleather three pin boots are 44 ounces each.

I use size 45 Sportiva trail runners, for a generous fit in the toes, and the 28 Siderals give me a perfect two finger shell fit.

Tension of the lower buckle can be adjusted by seating the wires in different grooves across the instep. Carpet testing indicates that this works.

As is the trend these days, the lean lock and upper buckle are integrated. Open the buckle and hook retracts. Close the buckle, and the hook lowers into the slot and grabs hold. There is a bit of wiggle when the cuff is locked.

The range of cuff motion in walk mode is stunning, forward flex is almost as free as the TLT 5, rear flex is free-er.

Three options for forward lean, with easily swappable plates. I’ll try the most upright setting first.

Beefy soles.

The Palau liners have a funky but effective lace; pull to tighten and stick the velcro tab to close. Without molding they’re a bit big for my low volume feet. The oven and insoles should take care of that. The plain black foam around the ankle and achilles is more flexible stuff, though not as flexible as the neoprene used in the TLT5 liner.

As is appropriate with something as important as footwear and as expensive as AT boots, I spent a lot of time thinking about this one. After last winter I was convinced that plastic boots were not appropriate, or least very sub-optimal, for use with three pins. At the same time, the performance and warmth of plastic and foam is undeniable. So the number one priority for this winter was to try Dynafit, not just as a tool for backcountry alpine skiing but as a tool for rugged nordic touring. Straight away my search was limited to the lightest of AT boots. I was sorely tempted by the lightest, non-carbon rando boots (Dynafit PDG, Scarpa Alien), which would have been 8-10 oz a boot lighter, and probably walked a bit better. In the end cost and fit had me doubting both. I tried on the TLT5s, and found them to fit very well except for serious pinching along the sides of my midfeet. I thought the PDGs might do the same. Scarpa, rumor has it, still has that horrid bump on the instep of their ski boots which never suited me. Used F1s were eliminated for the same reason, and their lack of step-in cramponability. When an opportunity to get a great deal on the Siderals came up, I trusted in history (20 years of wearing Sportiva climbing shoes, almost a decade in their trail shoes) and ordered. The beefier boots would probably ski a bit better for casual powder-hunting and the full shell would keep snow out without futzing. Carpet testing this evening suggests that the hypothetical foot around which Sportiva lasts their stuff continues to match my foot very well. I’m excited.

Watch the pingbacks and comments for updates once I get them on snow.

24 responses to “La Sportiva Sideral: numbers and rationale”

  1. I think it is going to be primarily a telemark winter for me this winter. What binding are you planning on using with these?

  2. I bet once you have your AT setup you’ll hesitate to ever go back. Unless it’s to spite the world and be a hipster or fit in with Amber (who will be converted yet!)

  3. What kind of skis do you plan to use with these boots? it will be interesting to see your results for nordic touring using an AT setup, as I am planning to go the same route

    1. Karhu Guides at first, as I already have them. Ideally I’ll have a skinny, fishscaled ski for distance stuff and a much fatter, rockered ski for powder hunting.

  4. Very interesting, Dave. Thanks for the post! I’m thinking about something similar. I’ve been using very light NNN BC mostly for going long distances on easy terrain but would now like to have something that could also make downhills more fun and also work for kite skiing… If I just could afford this stuff!

    A spesific question: How is the fit of the Siderals compared to TLT5s compared to La Sportiva trail shoes? I have quite a wide feet and also need/like a deep heel cup (something found on La Sportiva Wildcats) so I’m wondering what would be god fit for me…

    1. It is pricey, to put it mildly.

      Evaluating fit of plastic boots is pretty complex; what follows is based on carpet testing without molding the liners.

      I found the heel retention in the TLT5 and Sideral to be good, with an edge to the later. This probably has more to do with buckle placement than anything, but the Siderals do have an extra plastic bit which sticks up above the achilles. The forefoot width of both boots seems comparable, but the Sideral has more volume. Midfoot of the Sideral is a fair bit wider, this was the area which seemed like a no-go on the TLT5. Finally, the Siderals lack the multi-parted flex zone in the toe which the TLT5s have, and thus the Siderals should be easier to punch out should you need it.

      I have a very low volume foot, with a moderately wide fore and midfoot, and a very skinny heel.

  5. Excited to see how this setup works for you…I’ve been scouring the web for reviews of these as the TLT5’s were a no go for my foot. I’m also curious about the race bindings for nordic touring. I find I get a bit of a “high heel” feel on flat terrain even in the lowest position of my dynafit verticals.

    1. I was frustrated by the lack of early info as well, which is why I posted so many photos so soon.

  6. I’m curious as to what drove you away from plastic 3-pin boots? Did you lose too much power from those modified t3’s? On the other end of the spectrum, any thoughts on the new Rossi BC x12’s? Your still using the x11’s for your lighter skis right?

    1. Two distinct, but interrelated things. First, there’s a limit to the comfort of rigid plastic boots on multi-day stuff, which is why I’m using the pleather boots for skinny skis. Second, tech race bindings are so stinking light.

  7. Molded the liners this evening. They do just fine with standard home-oven techniques, but two people’s worth of hands to hold the shells open is absolutely required. Between the molding, lacing on the liner, and the heel cup of the boot heel retention is excellent. I was less than impressed with how little the midfoot foam puffed up, and may end up having to add another insole to keep my feet anchored as they pack out.

  8. Dave,

    Have you gotten enough snow out of these past few storms in your Northern portion of the Rockies to take the Sideral’s out more? If so, how do their touring abilities on the rolling/flat stuff compare to the Rossi BC X11’s? I’m in the market for a boot to fill the gap between fast nordic ski boots and Scarpa Maestrale’s, and a prodealed pair of Sideral’s may fit the bill.

    I can only assume that you’ll throw up a more detailed review in due time, but impatience and a desire to spend more time out in the finally covered high country is getting the best of me.

    1. A complex question which will get it’s own, long, post in a few months when I’ve got more ski miles in.

      The first question is whether light plastic boots and Dynafits will work for rugged nordic tours The second is if the Siderals (or any other boot) will fit your feet.

      With regards to pure forward range of motion, the Sideral/Plum combo is just as good as X11/3pin. You get that freedom from different spots, obviously. When breaking trail and skating, I don’t think the lack of forefoot flex is any kind of detriment. When diagonal striding on firmer snow or in broken tracks I do notice the lack of forefoot flex, but it’s not a huge deal. The total free pivot in the toe is a bit odd compared to pins and duckbills when moving the ski around in thick brush and the like. A nordic setup with tech bindings might favor a different mounting point for this reason, but in what direction I’m not yet sure.

      Transitions are an issue with tech bindings, mainly that its a pain to go quickly from ski to walk mode. You can ski down stuff with just the toe, but the sideways release value is pretty low (even with locked toes). I can’t imagine you’d hurt anything doing this, just release a lot at potentially inconvenient times.

      The main issue will I think end up being how unforgivingly stiff plastics boots are. Every time I’ve worn plastics all day my feet are sore, even with all the fit tricks and conditioned feet. My touring T2s from last year got canned because the inside ankle bone packed out the liner and eventually got bruised pretty bad. Not sure if I’ll need to put cant rivets in the Siderals eventually, but I’m prepared to. I’ve always hated wearing plastic boots, be it while skiing or ice climbing, and in the end they may just not be for me. Some people will I think be much less sensitive to this, but it will be an issue nonetheless.

  9. Dave,

    Thanks for the in-depth response.

    My Scarpa Maestrale’s, coupled with Dynafit bindings have been great for steep descents, which I’m getting a bit away from these days. This has given me experience with the motion at the toe in touring mode. However, I have not ever used 3 pins, but am considering them since their accompanying boots are so damn cheap. The oft burdensome transitions are definitely a downside to tech bindings, and something that bears repeating. There is lots of food for thought when picking out a ski setup for touring.

    Thanks for pointing out a new option in the AT landscape, and I look forward to an in-depth opinion when the time comes.

  10. Maybe something like this mod would work to make ski to tour transitions quick:

    I’ve thought about attaching a bit shaped to slip down between the pins to the handle of one of my poles which might be lighter then what Lou did.

    There is also a trick mentioned in the comments of that post that lots of people use to go ski to tour by twisting the heal piece in a way that causes safety release. Not sure it works with race bindings.

    1. It’d be hard to do with race bindings. Nothing that would make getting that leverage very easy.

  11. […] In short, while I haven’t put enough miles into them to have a final judgment, thus far I’m pleased with the investment. For more detailed pictures and weights, look at my initial post here. […]

  12. […] the mile downtown in ski boots, early in the morning, was just as introduction.  I drank a macchiato in the coffeeshop, the […]

  13. […] AT rig, shown above, is 176cm Black Diamond Current skis, with Plum 145 race bindings, and LaSportiva Sideral boots.  As a quiver of one for my not especially rigorous uses, this amalgamation has been quite […]

  14. I switched from telemark to tech this season. Not going back, even though I love the telemark. I am skiing in the Siderals, too. So far (sixty days) I really like them. I am three times the skier simply by going to AT. The hassle of switching between modes with the Dynafit Radical STs is my main complaint. A new tech binding from Fritschi, the Vipec, weighs the same as the ST and switches readily between modes with a lever at the heel. It has some other virtues as well. The Vipec may be a good choice after a year or two on the market.

  15. Got the Vipec v. 2, and have skied them six days this season. They have several virtues. It is not necessary to “lock” the toes for walking. I have not walked out of them even on steep sidehills. They are adjusted very light, 5.5 DIN. The lateral release is in the toe pieces, which means they can release in the event of a slide while ascending. Changing mode on the fly is easy (once I learned the moves). Going to Walk mode is easily done with a pole tip. Returning to Ski mode, for me, requires reaching down with a gloved hand to lift the heel lever. Some people can do it with a pole handle, but my poles (old LifeLinks) aren’t well-shaped for that. And last, the brakes, if you chose to mount them, are aggressive and look as though they might actually work on hard snow. Last season I used Dynafit Radical STs, whose brakes are largely for looks.

    The Vipecs keep the weight equal to the Radicals by using lots of plastic. Very tough plastic. My pole tips leave no marks on them. The plastic’s got to be very strong since skiers weighing up to, say, 250 lbs are stomping on the heel elevators. I haven’t had a release yet, despite skiing up and down over lots of thinly covered deadfall. That’s a good sign.

    Still like the Siderals. They feel like warm comfy house slippers walking and are the best boots I’ve ever used downhill. Full disclosure: last alpine boots I had were leather Molitors, laces within and without, c. 1968. Pretty awesome in their day.

    Some obvious advice about boot fitting: Walking comfort is crucial, since most of the time that’s what you’re doing in the backcountry when in motion.

  16. How do these fit you? Don’t you run 44.5 or 45 in LS trail runners? Mondo 28’s seem like they’d be way to small unless they ran real big.

    1. Ski boots need to bit fit differently. Theyre the right size, and i usually buy 45 in Sportiva.

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