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Under Armour Speed Tire Ascent Mid Performance Review – A Better Fat Tire

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Under Armour’s Fat Tire featured new and innovative tooling designed for a very specific purpose: trail running. Now, that tooling has made its way into the high-fashion UAS line and onto the feet of a number of UA athletes — and regardless of its aesthetic appeal, it works. The Speed Tire Ascent Mid is the necessary update to the original Fat Tire, with the added bonus of a Boa Closure System. I beat this shoe up over almost 100 miles, so let’s get into it.


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Traction – Excellent. The Michelin Wild Gripper rubber outsole compound is durable and offers traction on almost any surface — wet trails deep in the woods, snowy mountain passes, concrete, cobblestones, etc. The uncertainty of a rock scramble disappears when you have traction like this.

The only time I slipped was in men’s public restrooms, and there are obvious reasons for that that I will not explain here (my forehead missed the urinal by an inch).

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Cushion – The improvements begin here. The cushioning used on the Speed Tire Ascent Mid is a combination of the full-length Micro G midsole and removable Charged Cushioning sockliner (that is antimicrobial), and it is sublime.

Micro G may be the best, but the real winner here is that this Fat Tire features a slimmer, lower-profile tooling with much less bulk. The Speed Tire Ascent Mid is considerably lighter and much less bottom-heavy than the first Fat Tire Low. At times, the original Fat Tire — while supremely comfortable — simply felt like a lot to lug around on-foot. That is gone with this update, and no comfort is relinquished for a thinner setup.

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Materials – You may not make it into the Marquee in New York or any London nightclub with these on (which I learned), but what you sacrifice in aesthetics you’re getting back twofold in function. The Speed Tire Ascent Mid utilizes a durable synthetic soft-shell upper that is a bit stiff but will eventually crease where your foot needs it too. The inner neoprene bootie, that the shell upper wraps around, is stretchy and durable; it has shown no signs of wear after all these miles.

The upper is coated in a DWR finish that repels water and keeps things breathable. Short of submerging your foot in a body of water for a length of time, your feet will be kept very dry in this shoe. Muddy swamps, deeper-than-you-thought NYC puddles, snow — your feet will stay dry. The Speed Tire Ascent Mid is kind of like a wetsuit for your feet.

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Fit – Yes, it is a difficult shoe to get on, but once it’s on you’re locked in with or without tightening the Boa system — and this system should be the standard for almost every shoe.

However, the one glaring issue I had was that the Boa Closure System on the right shoe sat right beneath my lateral malleolus (outside ankle bone) and just ground away at it — it was terrible. I’ve got a scar there now, and now that I’m done testing these, I only wear them for short outings with thick socks. I would definitely try these on, because the minute I did I felt that issue. Otherwise, the fit was great, it’s just my foot shape.

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Support – This iteration of Fat Tire tooling has a much flatter base than the rather round and bulging original. With that, the shoe feels much more secure, and less like you’re standing on a big pillow. There is some arch support (that will improve as your foot forms the sockliner), and the thick tooling provides torsional rigidity.

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Overall – Besides for the fit issue due to my foot shape (just the right one), the Speed Tire Ascent Mid is an excellent example of what you can do with modern synthetics and a closure system superior to traditional laces. It is a shoe that is comfortable enough to wear for as long as you need, and it will last a good long while. Moreover, it’s a significant improvement to the original Fat Tire. Even if you never run trails, this is a great option for $140 (and it’s .

Buy the Under Armour Speed Tire Ascent Mid

under armour speed tire ascent mid scorecard

  1. I was very curious about how these lower fat tires would perform. I’m getting a pair now. Good performance review by Noah.

        1. imo, the mid is the one worth buying. The neoprene bootie offers insane protection against the elements, and it was only my right ankle that had that issue — was flawless on the left. Let me know how you enjoy the lows.

  2. Do you happen to know what physical stores carry these? I’ve been looking for a new hiker/trail runner and these look very intriguing.

      1. Thanks. I can’t find these in stores anywhere. Do they have a heel counter? I need that ankle support for trail runs and hikes.

  3. Great review, are you planning to review the fat tire 2? Wondering how that would compare since it also uses the Boa system.

  4. Hmm, love the look, idea, and flatter sole. How is the lateral support? Wondering if I could use them​ cross training. Currently using the Under Armour Micro G Limitless, (which is phenomenal) but it has very little traction and is designed for the gym. Now that spring is approaching, I was looking for a more all terrain type shoe for outdoor training etc.

    Thanks for the review and any advice. So happy to see Micro G in a higher end shoe.

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