These are barely more than skimo race boots. That is a good thing. They are light, transition fast, have amazing cuff range friction (or lack thereof), and ski downhill adequately well. The downhill performance is dependent on good technique, excellent fit, and appropriately matched equipment. The biggest ski we used with them is 95mm underfoot. Most would say this is "pushing it", but we found it to be a great match. The Sytron doesn't insulate very well and has some fiddly usability issues. Neither of these complaints is enough to really sway your choice, but we need to mention them.
La Sportiva Sytron Review
Compare prices at 2 resellers Pros: Light, excellent touring range
Cons: Thin construction makes them cold and tougher to fit, some usability issues
Manufacturer: La Sportiva
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Our Analysis and Test Results
Backcountry ski boots exist along a broad spectrum. At one end are those boots that are fully specialized for skimo racing. Except when on the feet of very high-end practitioners in limited and controlled conditions, race boots just aren't appropriate for actual backcountry skiing. The very next step "up", though, has genuine potential application in the backcountry.
The La Sportiva Sytron sits right in this very next step up. It is just robust enough to qualify as a backcountry skiing boot but has many of the advantages of a skimo race boot. It is ridiculously light and touring-ready. The boot is arranged such that transitions are quick and simple. The boot can be configured such that, depending on the cuffs of your pants, your switch between ski and tour modes is one fast move. Downhill you will certainly experience compromises.
However, we are confident that you will be pleasantly surprised with the downhill performance of these boots. The best we can report is that our lead test editor used these on an 8000 foot day of amazing powder skiing in Grand Teton National Park. His skis that day were our Editors' Choice BC ski with a 95mm waist. In the interest of thorough testing, this same tester used the same skis in similar (or even better) conditions just two days later for 10000 feet of touring. The tested boots on that next day are heavier and stiffer. He enjoyed the performance of the La Sportiva Sytron more. Much of this can be attributed to the fit of these respective boots; the Sytron fits him way better than the compared, "better skiing" boots. That the Sytron even enters this conversation, though, is high praise.
They go up hill darn good; top of the heap in our test range. In assessing uphill performance, we look for cuff range of motion and friction. The Sytron has more range than your ankle does, and virtually no friction in that range. The thin liner is flexible, and the shell components are engineered to have minimal interference with one another. You can't get backcountry ski boots that tour better than the Sytron.
We separate weight out from touring performance, but they are of course related. In this case, the Sytron is also at the top of the charts. Just over four pounds for backcountry ski boots is phenomenal. You can go lighter, but you then enter the high-end skimo race category and lose all kinds of versatility.
You will have to adjust to the downhill performance of the Sytron. The flex is stiffer than you might first expect, but the cuff is low, and the thin liner lends a feeling of instability. These lightweight boots need to be fit real, real close for optimum downhill performance. Our lead test editor is lucky that the Sytron fits his foot very well; every other tester on our team needed to work on or adapt or size up the Sytron to make it work downhill. Their perceptions of the downhill performance of the Sytron are correspondingly tempered even further. No one will suggest that the Sytron is a high performing product on the downhill; they are "just enough".
Comfort and Fit
As noted above, super light boots need to be fit very close for optimum performance and the thin liners that are usually included make comfort even harder to accomplish. Further, the shell thinness and materials are very difficult, if not impossible, to adjust. Aim for an excellent fit "as is". Try these on. The good news is that there is an ever-growing list of boot models, with differing fit characteristics, in this category.
The Sytron, like other La Sportiva ski boots, is narrow through the forefoot with a slightly more generous heel pocket. La Sportiva calls the last width of the Sytron 100.4mm. This is relatively wide/high volume. The experience of our test team suggests that the fit is narrower than this number would suggest.
You keep your feet warm in boots like this by moving fast and not stopping. The boots offer very little insulation, relative to other, sturdier AT ski boots. The liner and shell are both nearly as thin as is possible. This lightens them up for the uphill but offers precious little insulation. Further compromising the warmth is the fact that you absolutely need to fit these boots close for optimum performance. You won't want to size them such that you could fit a thicker liner in there. With more room between your foot and the shell, no matter what liner you fill that space with, the performance will fall below levels acceptable to most people.
We somewhat joke about keeping warm by moving fast and not stopping; this is an aggressive risk management strategy, especially when the consequences include losing digits or limbs to frostbite. If you are forced to sit still or slow down with super light AT ski boots, you are toying with major issues in the significant cold. Our lead test editor has extensive experience, sometimes on major and cold expeditions, with super light ski boots. He has had good luck with carrying puffy pants (yes, even in the "Lower 48" on day trips) and, in some situations, using overboots. Either strategy does indeed compromise your efficiency, but you still get the easy uphill touring of skimo slippers. Proceed wisely.
Ease of Use
The Sytron is finicky at best. This doesn't seem to be necessary. The main issue we have is that the boot is tough to get in and out of. One tester, finishing a hard and fast workout on skis early in the season, drove home in the boots (thankful again for the flexible and generous cuff mobility) and had his SO help him out of them. Getting in is even harder. The issue is mainly the fabric "gaiter" that seals snow out of the lower boot shell. The ankle opening of this gasket is very snug.
Another usability issue we had is with the cable-actuated ski/walk mode. This cable allows for "one move" transitions, but is finicky. On one occasion it seemed to ice up. On another, for another tester, it bound up in some way. In both cases we were able to remedy the situation in a few minutes, but the efficiency gains of dozens of transitions were consumed in that process. Finally, a piece of rigid foam that fills a void beneath the heel of the liner came unglued in both tester boots. This makes liner removal and insertion annoying at best.
On the flip side, we dig that La Sportiva equipped with Sytron with a forefoot buckle that has two clear and readily exchanged tension level. Just like with the cuff, you can loosen it for the uphill and make one move to tighten it for the down. This is clever and appreciated. Other boots would benefit from the same thing.
The price of boots in this category are steadily coming down. It used to be that you'd have to spend over $1000 for a boot in this category. The products have simultaneously improved and reduced in price. The Sytron is right at the forefront of both these trends. They're not super cheap, but they won't break the bank.
If they fit you, these are excellent fast touring ski boots. They can be pressed into serious skiing with "real" skis, or matched with whatever equipment and reserved for fitness and gentle touring. There are some frustrating issues with them, but the value and performance will likely justify their place in your kit.
— Jediah Porter