With the Curry 3, Under Armour officially joined the woven brigade for performance sneakers, putting its Threadborne material on the lateral side of the shoe. While not as flexible as other wovens on the market, it offered structural stability while still allowing for some freedom of movement. Now, Under Armour brings us the evolution of that material: the Threadborne Slingflex.
Utilizing the same materials as the Charged Controller, the Slingflex also adds Dyneema, the “world’s strongest fiber,” into the mix, to provide even more durability and stability. Does it add up to make a great runner? Only one way to find out. Read on, true believers…
While running shoes aren’t known for traction, if it sucks, you will find out quickly. Take a paved road, add just a little moisture, whether rain or early morning dew, plus a hard rubber traction, and you get a run that turns into a Disney short cartoon real quick. Luckily, the Slingflex doesn’t suck. Solid rubber covers the forefoot and heel with a slight bridge on the lateral midfoot.
However, the rubber only covers the strike points. Segmented areas and voids cover the outsole, making the traction even better – the deep forefoot grooves allow the shoe to flex while striding, giving the shoe more traction grab. Wet, dry, sunny or not, the Threadborne Slingflex worked perfectly.
As far as durability goes, the pair in the above shot has almost 100 miles on it, which isn’t much for runners, yet the pattern looks exactly the same as new. Dirty, but the grooves and details are all there.
This is what Charged should feel like, although the UA Running division has handled Charged Cushioning correct since day one. On the Threadborne Slingflex, the black foam with the Charged label is the more plush top layer — it softens your steps and absorbs the downward forces. The white layer is the stiffer foam — it is responsive and low-riding. The best part? It works as advertised.
The step-in comfort is there from minute one, but soft shoes make your foot tired. That is when the responsive layer springs back and propels. If you look closely, you will see the compression wrinkles in the midsole. Do you notice more creases in the black than the white? That’s the effect.
This may be the second best foam on the market, and compared to the Charged in the basketball line, it feels like an entirely different material — or at least a different combination. There was no jarring or pain on short runs (3-5 miles is about my limit on non-playing days) but anytime I went over I could feel some fatigue setting in. I never felt this on the Gemini 3 (review coming soon), so the thinner layer of Charged in the Slingflex makes this shoe more ideal for short work, sprints, intervals, and speed training.
Freaking lovely. Honestly, and we at WearTesters hate to compare shoes, but this is the closest thing to UltraBoost Primeknit I have felt. The Threadborne is true sock material and feels great on-foot, with or without socks (yuck, I know, but sometimes you want to feel the breeze on your toes). The toebox is amazing because it flexes with every bend and sits right on top of your toes yet never feels restrictive.
In the black section above you can see the white Dyneema threads running lengthwise along the toebox, so flex isn’t compromised. On the side panels, the black is a tighter weave for support and fit so there’s less stretch. The heel is tighter still and features an internal counter that is solid. Most wovens keep the heel counter soft for that sock-like comfort, but if you want a high-intensity performer, that support is needed. The tongue is open mesh and soft padding, but lace pressure isn’t a problem here because the thick laces and good lacing structure will keep your foot happy.
Length is perfect in true to size, about a half of a finger between the big toe and the end of the shoe. That’s just enough for some expansion while running, whether from toe splay or swelling, without feeling sloppy and clownish. Again, the toebox is right there, but never in the way, so rubbing and blisters are good as gone. The midfoot, with the tighter weave, really saddles your foot and holds you over the footbed. The ankle/heel area is lightly padded but in the perfect spot — around the collar to help lock your foot in.
The lacing system on the Threadborne Slingflex is one of the simplest I’ve seen, but simple works best when done right. The thick lace holes keep the laces from sliding out and loosening while running and the placement high up on the foot helps hold it all in. Under Armour has had fit down since the start, and the Threadborne Slingflex keeps it tight.
If there is one area that may be lacking in the Threadborne Slingflex it is support — but only if you need a supportive shoe. For neutral/mechanical runners, there is enough structure in the Threadborne Slingflex to keep you happy.
Again, the heel cup is internal and stiff, but cuts fairly low across the heel so it doesn’t feel clunky or restrictive, it’s just there to lend a hand. The lacing structure is wide enough to lock you in and almost works like the lace straps on the adidas basketball line (Explosive, Boost 2016, etc.).
There is no midfoot shank that I could find, but the stiffer Charged foam is more than enough to hold if short distance running is in your plans. If you have had plantar fasciitis or need that extra arch support, then the Gemini may be more for you. If you enjoy a free-feeling, less restrictive runner, the Threadborne Slingflex is it.
The Under Armour Threadborne Slingflex may be the most comfortable shoe this year. I know I said we don’t like to compare, but we all do it in our heads, so here goes: next to the adidas UltraBoost’s Primeknit, the Threadborne Slingflex uses the best woven upper on the market. The way the upper flexes and moves is magic, and there is a serious tendency to forget you are wearing the Threadborne Slingflex.
If you are in the market for a sneaker with great fit, great materials, and good cushioning for working out, running, and throwing on after the gym, the Threadborne Slingflex is the one. Priced at $100 USD, this is a hard shoe to let go. If you have been waiting on Under Armour to let loose and give us a classic this may be the beginning of a beautiful future.