Gear Review: Aku SL Sintesi Mid GTX Boots

Aku SL Sintesi Mid GTX
Aku SL Sintesi Mid GTX

Aku SL Sintesi Mid GTX
$250, 2 lbs. 14 oz. (men’s Euro 42.5/US 9)
Sizes: men’s 7-13

When I need a sturdier boot for carrying a heavy backpack, I prefer one that incorporates some climbing-oriented features that improve traction, fit, and durability. I wore the SL Sintesi Mid GTX on a five-day, roughly 44-mile family backpacking trip in Washington’s Glacier Peak Wilderness, starting out with more than 50 pounds in my pack (including family food and gear), and found it does all of that, providing excellent support while feeling like a lighter, more nimble boot.

A superior boot begins and ends with superior fit, and the Sintesi clears that bar, cradling the heel to prevent any slipping that can lead to blisters, supporting the midfoot and arch, and leaving wiggle room for toes without allowing my foot to slide forward and hammer my toes on descents. The close lacing, extending nearly to the toes (like shoes and boots designed for climbing), helped dial in a more precise fit that gives this burly boot a more nimble feel. The relatively stiff, triple-density EVA midsole delivers enough support and cushion for hauling 50 pounds in rugged terrain, while the slightly narrow platform and smooth, sticky portion of the outsole beneath the toes let me scramble off-trail on steep slabs. While weighing nearly three pounds, the boots didn’t feel heavy and clunky when I dayhiked one evening from our camp west of Suiattle Pass about 6.4 miles round-trip to Image Lake.

The suede uppers conform to the shape of my feet, and a protective rubber rand stretches all the way around the forefoot and wraps the heel. The above-the-ankle height and ample padding in the collar and tongue offer plenty of protection from bashing into rocks. A Gore-Tex membrane kept moisture out when I walked through shallow creeks and kicked steps in wet snow crossing Spider Gap. Deep, well-spaced outsole lugs gripped well in mud and snow and on rocky trails. Lastly, construction is superb, and the Sintesi comes with a footbed that gives a little more support than standard footbeds found in most boots. The fit is best for medium-volume feet.

See all of my reviews of backpacking boots, including a model comparable to the SL Sintesi Mid GTX, the Scarpa Tech Ascent GTX.

NOTE: I’ve been testing gear for Backpacker Magazine for 20 years. At The Big Outside, I review only what I consider the best outdoor gear and apparel. See all of my reviews by clicking on the Gear Reviews category at left or in the main menu.

—Michael Lanza


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4 thoughts on “Gear Review: Aku SL Sintesi Mid GTX Boots”

  1. Hi, I was wondering if you would recommend these boots for an average day of hiking as well as backpacking. I’m about to retire a pair of Merrell’s I’ve had for 6 years and my biggest complaint was that they were one dimensional, I took them backpacking, but they weren’t really sturdy enough. I am looking for a good all around boot that I could wear in intense mountainous/snowy condition or on a casual day of hiking with the fam. I think I’ve narrowed down to these, Salomon Quest 4D GTX, Vaque St. Elias, and the Oboz Bridgers that you also reviewed. Any suggestions?

    • Hi Andrew,

      That’s a good question that I get occasionally, from readers and friends, and my first response is always cautioning against trying to buy one boot for everything from light dayhikes to heavy-duty backpacking. It’s not that you can’t wear one pair of boots for all forms of hiking, it’s simply that it’s hard to find one pair that does everything well for you. You might wind up with one pair of boots that you don’t love for either dayhiking or backpacking. One pair may save you money in the short term, but possibly not in the long term if you wear them out faster than if you have one pair of shoes for dayhikes and one pair of boots for backpacking.

      But I’ll try to answer your question. Yes, you could wear any of the boots you asked about for both dayhiking and backpacking. The Sintesi, Salomon Quest 4D GTX (which I just noticed has marked down significantly), and the Vasque St. Elias GTX are intended more for heavy-duty backpacking, so they’re heavier, stiffer, and hotter than I prefer when dayhiking. The Salomon Conquest GTX ( and the Oboz Bridger are a bit lighter and more flexible as a crossover boot, as are the Scarpa Tech Ascent GTX (, while still giving you the support and protection for backpacking in wet or snowy conditions. You may also want to consider a boot that’s even lighter and more flexible but has support for backpacking with a moderate load, the La Sportiva Hyper Mid GTX (

      Everyone’s feet are different, so I don’t know how much support you need for backpacking or how much you prefer for dayhiking. You might get lucky and discover that one of these models (or another) is the perfect, all-around boot for you. But as I suggested above, you should consider whether your goal of finding just one pair of boots (and if you have economic reasons, so be it) is important enough that you’re willing to accept one pair of footwear that isn’t perfect for either dayhiking or backpacking.

      You may want to read the relevant advice I offered in this post, answer another reader’s question:

      Good luck.

  2. hello, my name is andrea are very interested in aku sl summary, I found a great deal online means more than my number. I can buy them? thanks Regards

    • Hi Andrea, I’m not quite sure what you’re asking me. But if you’re asking me whether I suggest you buy boots online without having ever seen them, I’d say no. I suggest you try on boots and walk around in them before buying, to make sure of the fit and that you like how they feel.