Color: Core Black/Black
adidas's marketing pitch: Greatest running shoe ever.
Surfaces tested on: Road, ambient temperature of 25° C/77° F.
Upper: Primeknit stretch mesh, closed stretch mesh, plastic midfoot cage.
Midsole: Expanded Polyurethane Foam made by BASF-adidas. 10 mm heel to toe drop.
Outsole: Single perforated sheet of soft rubber.
Weight: 333 gms/ 11.74 Oz for a half pair of US11/UK 10.5/EUR 45.3/CM 29
Widths available: Single, D-standard (reviewed).
US MSRP: $ 180
adidas’s North American headquarters is situated on N. Greeley Avenue in Portland, Oregon. If you were to drive straight out of Greeley and then further west on Hwy 26 for another 80 miles or so, you’ll hit land’s end, or the mighty Pacific ocean. The entire coastline is dotted with magnificent rock formations and beaches, battered by millions of year’s worth of weather elements, bird droppings and angry waves.
All these places are great to spend a lazy afternoon on. There’s plenty of variety too; some stretches are sandy, while others are gravelly, with giant logs of driftwood deposited by rivers flowing from deep inside the enchanting Pacific Northwest. The water is always freezing, yet proves to be a poor deterrent for people who come and visit. If they’re lucky, they might find an orange Sea Star to take a picture of.
It is inevitable that you’ll strike up a conversation with one of the locals, and it is also very likely that your new friend might point at a huge monolith and say something like, ‘this is the most photographed rock in the United States.’
You realize that he means it; but you also know that can’t be possibly true. Most of these collosal sea stacks are formidable geological formations and truly deserving of local pride, and it could be the most photographed rock in Oregon and Washington state. Ok, maybe on the entire length of West Coast. But the continental United States? Nah.
So when adidas says things like that the Ultra Boost is the ‘greatest running shoe ever’, it might be because of two reasons. The first is genuine chest thumping anchored in the knowledge and pride that they have a stellar thing going with the Boost foam. Similar to how our friend on Oregon’s rocky shore felt, and hence the former analogy.
The second could be synthetic (and intentional) trumpet blowing, meant to allay the angst of shareholders who want adidas to perform better both on the Wall Street and North America. adidas urgently needs a slew of products which can command not only coolness but also respect, and what better way than to pin your hopes on the successful Boost platform?
You might think we’re dissing the Ultra Boost; we’re not. The newest $180 intro is a very good shoe, blending two of adidas’s newest and most marketeable – the Primeknit upper construction and a high volume Boost midsole. But throwing around the ‘greatest’ hyperbole isn’t exactly the smartest move; there is no running shoe in the world which is a universal fit for all.
Like most running shoes, there are a number of things we like about the Ultra, at the same time counter balanced with areas which could do with a leg-up. So calling a shoe ‘greatest’ is setting it up for a case of over-promise and under-deliver.
So far, adidas hasn’t made a strong showing of its Primeknit upper in its performance running line, except for the occasional release like the Primeknit Boost. The German sportswear giant is attempting to change that, with more releases making use of the knit upper. The Ultra Boost is one, and we’ve starting to seeing pictures of a Primeknit Boston Boost, so these are obvious clues hinting at the future shape of what may follow.
On some level, the Ultra Boost is similar to the Energy Boost 2. The two models can be compared on shared traits like a compressive upper, plastic midfoot cage and heel, and a prodigious chunk of exposed midsole hewn out of bouncy Boost foam. Even the plastic ‘Torsion’ shank dams up on the Ultra Boost’s medial heel the same way the EB-2 does. At the same time, the two differ on the quality of fit and cushioning behavior, and as always, we’ll talk about it at length before the sun goes down.
This might be a good time to momentarily touch upon the topic of the annual Energy Boost refresh. After being consistently refreshed for two years, there’s radio silence on whether a third iteration of the Energy Boost will follow. Is the Ultra Boost the replacement for Energy 2? That thought is not far fetched, for a couple of reasons. One, it looks like Primeknit (in its multiple avatars) is going to be featured on a lot more models going forward, and the Ultra kicks that journey off in style.
Secondly, the Energy Boost’s price was unchanged for two years at $160, and assuming there was a 5% retail price increase, the imaginary EB-3 would have been around $170. That would have placed it uncomfortably close to the Ultra, and would have made no merchandising sense at all. But if the $160 price point is eventually vacated, then there will be a huge pricing vacuum between the $130 Glide Boost and the Ultra. What adidas should do is to replace the Energy Boost with a new $150 model which will go head to head with competitors such as the Asics Nimbus 17, Nike Vomero, Brooks Glycerin and Saucony Triumph. Might also be a good idea to thrown in a ‘stability model’ while at it.
Coming to think of it, this is the first time we’ve come up close and personal with adidas Primeknit on solereview. We were always curious to find out how adidas Primeknit compares against Nike’s version, which by the way, comes in different iterations. Like the super compressive Nike 3.0 Flyknit, or the more easy going version on the Flyknit Lunar. For now, we can only judge Primeknit based on its use in the Ultra Boost, but as time goes by, we should be exposed to more variants.
The Ultra Boost upper isn’t pure Primeknit, but rather a hybrid which uses elastic-knit in forefoot and midfoot, and a bootie construction in the rear which relies on traditional stretch fabrics.
If you own or tried on a pair of Energy Boost 2, then it is easier to draw a parallel from a material standpoint; this is akin to Techfit stretch in the front and a traditionally designed rearfoot.
Like engineered meshes, the single piece Primeknit has multiple zones of stretch. Meaning, it feels more elastic in places like the top of forefoot, while the edges and toe bumper have a closed knit construction for better structural support.
Ventilation is also based on zones; the forefoot top is more porous and breathable, which also makes it more accommodating to stretching.
Push up on that area with your fingers, and one gets an idea of compression levels. The elasticity is more relaxed than tech-fit, and also shoes such as the Nike Free Flyknit. But the forefoot isn’t 100% Primeknit.
There is an internal toe stiffener lined beneath the fabric, and that’s something you can feel when you wear the shoe or when simply running your fingers along the inside edges. It’s hard to see it from the outside, so we’ve included a picture of that later in the review.
The Ultra Boost upper abandons the use of a regular tongue and collar design, and instead adopts a full bootie construction, which means that the walls of the rearfoot opening run broken. To make it easier for the foot to slide in, the collar fabrics are elasticated, coupled with an exaggerated Achilles area.
The mega pull tab is a visual oddity yet functionally effective, and comes in very handy when putting the shoe on. Talk about reflectivity, and there isn’t much to show for. There’s the tongue label which semi-shines in low light, and that’s that.
Collar is comfortably cushioned with foam, and so is the upper part of the tongue. Actually, the entire upper lining of the midfoot is padded. This helps dull the lacing pressure and prevent the corners of the plastic cage from potentially rubbing over.
Speaking of the plastic cage, don’t you think the contrast is a bit odd? On one hand, the Primeknit’s solitary goal is to deliver an accommodating or custom level of fit, its elastic fibers shaping around the contours of the foot.
On the other hand, a hard plastic cage is the polar opposite of Primeknit, and it is as rigid as it gets. The forefoot and midfoot may be made of the elastic fabric, but practically speaking, the cage kind of dilutes the midfoot Primeknit experience. Midfoot lockdown is taken over by the thermoplastic cage and not the knit textile, and the piece joins a large heel clip with an inwards flare.
Here’s our take on why the Ultra Boost uses so much plastic on what could have been a lightweight upper with unadulterated stretch. We think that the Boost midsole is inherently unstable once the foam volume crosses a certain threshold, and that is why adidas uses one (or sometimes both) of the two things – a plastic midfoot and/or a midsole rim.
The Supernova Glide Boost feels the most balanced when it comes to cushioning and support, and it uses a firmer rim over the Boost midsole. The Energy Boost 2 used both the cage and rim; the adios, Boston and Tempo Boost all use harder midsole edges. In addition to all this, most performance running models need the Boost midsole to be formed with a ridge – meaning a narrower Boost section molded on a wider base. This little noticed (and intentional) design feature makes the shoe more stable.
What happens if you remove the cage, rim and midsole sculpting? You end up with something like the adidas Pure Boost, which was a really terrible running shoe. No stability at all. Boost might be a superb cushioning platform, but far from perfect on its own. It best performs only when teamed up with supplementary design features.
To reinforce our point, a Boost running shoe needs to feature at least one of the stability elements. Either a plastic cage with midsole ridging (Ultra Boost), or a harder support rim with midsole ridging (Glide Boost). In our opinion, the midsole rim is the lesser of the evils, providing support while keeping the Boost ride signature intact. We were never fond of the plastic midfoot in the first place, and running over 30 miles in the Ultra Boost has done nothing to change that impression.
The silver lining here is that the Ultra Boost’s inflexible midfoot surrounding isn’t as bad as Energy Boost’s. The design allows you to have a greater amount of control over fit pressure compared to the Energy.
You see, there were a couple of factors at play on the Energy Boost which made the midfoot cage feel so restrictive. It was stitched tight and flush to the compressive upper, so it felt and behaved like an inseparable part of the shoe. The pressure over medial midfoot was particularly noticeable, regardless of how you laced the shoe.
On the Ultra Boost, the cage is stitched to the upper only in the front, where yes, the pressure feels slightly uncomfortable. But rest of the plastic has a floating structure and anchored only to the midsole edge. The first row of eyelets also rise up higher than their counterparts on the Energy Boost, giving them more liberty to move around at will.
The detached design helps the plastic cage dynamically adjust and move its position along with foot movement, and we think this was smart. You still feel the hard shell, but without the invasiveness of how Energy Boost felt.
A word of caution, though. The midfoot cage will become a problem if you fasten the laces too tight. So the key is to go easy on pulling those gold tipped laces, and keep things a bit relaxed.
Remember that the Ultra Boost has a sleeved upper, so let that do most of the midfoot lockdown instead of delegating that job to the TPU panel. This will also ease off top down lacing pressure.
Ultra Boost is short-laced, with only four rows of eyelets against a regular five or six. The chances are, you won’t miss the last row of cinching. The bootie sleeve like design of the tongue and collar delivers a level of wrap which few will find flaws with.
Plushness is foam packed under the lining, and the inwardly molded heel counter works together with the high Achilles lip to prevent heel slippage. It is worth underscoring that the plastic heel piece leaves the area running along the Achilles uncovered, a design aspect which runners with sensitive Achilles will love.
Upper forefoot is very shallow and has an extreme taper around the toe bumper. There’s less space inside the forefoot by default, and then the insole eats into whatever’s left. Like the Response Boost, the footbed sits on the midsole instead of in a cavity.
The net result is your big toe being pressed down by the Primeknit upper, though visually it looks like there’s plenty of space ahead of your toes. As far as sizing is concerned, we’d buy the exact same size as the Energy Boost Techfit.
We did not find barefoot use of the Ultra Boost particularly comfortable, for two reasons. The super snug upper medially rubs against the small toe over time, and will end up in blisters or skin chafe.
There’s also an internal toe puff which has the tendency to catch on the small toe – you can see that in the image above (the black strip right in the front). With socks, there are no issues, and the upper feels smooth and seamless.
When compared to the Energy Boost, the Ultra forefoot feels much more roomy, or should we say, conducive to adjustment. There is no open space, yet the Primeknit upper is better able to expand and fit around the foot. The Ultra also has a lower toe spring, which we also think contributes to the relatively forgiving nature of the shallow toe-box.
One area where the compressive forefoot adds value is in enhancing ground feedback; the midsole front is much thinner than in the back, and the upper does a great job at driving a better connection between the foot and running surface. This design also makes the forefoot extremely flexible, easily the highest level among all the Boost models reviewed here.
The last used is also different than EB-2’s, so that must be something to that too. If the last marking on the sockliner is anything to go by, then the Ultra Boost, Boston Boost, Energy Boost and Glide Boost all are based on different upper fit dimensions – at least on paper.
It is hard to accurately pinpoint specific differences just by wearing and trying to compare all, as materials and construction techniques differ (and hence influence fit) vastly.
Midsole design is fairly straightforward, and typical of how most Boost based models are assembled. The Ultra Boost differs slightly by not including any EVA bits. Much like the Pure Boost, the sandwiched layer is 100% Boost foam. A sharp ridge separates the upper and lower half of the Boost midsole, which results in a narrower section of foam molded on to a wider base.
Given the high volume of Boost and plastic use, the Ultra is not featherweight. It tips the scale at 333 grams or 11.74 oz for a half pair of US 11. Pretty much the median for traditional running shoes. To add some perspective, models like the Asics GT-2000 2, Brooks Ghost 6, Nike Vomero 9, and New Balance 1080 V5 weigh the same.
Ultra Boost comes with a Torsion shank – a plastic component which is attached to the underside of the foam midfoot. While we generally see a flat piece glued flush with the outsole, the footbridge here originates in a midsole cavity.
We’ve got a few theories around why this might be. One is that the stability could be helped by splaying of the open area, which should lower the center of gravity on weight loading. At the same time, the Torsion component sits closer to the foot that way, and helps increase the feel of midfoot stiffness. Also have this feeling that adidas designers might have wanted the Ultra to have a consistent soft feel from rear to front, and a flat Torsion shank could have spoiled the fun.
Closer to the upper, a perforated strobel separates the midsole and insole. The strobel is like what the footbed of PureBoost was; a sheet of synthetic leather with angular holes cut punched in.
Boost foam is exposed through these gaps, and if you were to hold the outsole against bright light, a part of the shine will illuminate the foam. This attests to the Boost foam’s expanded (and lighter density) construction, made possible by use of steam molded Polyurethane.
A compression molded EVA insole is used along with the lattice-like strobel. Not as thick as the one on Energy Boost; more closer to the type used on Boston Boost. A smooth fabric lining on top, and a textured underside which mirrors the grid like design of the strobel and outsole.
adidas calls its outsole design ‘Sprintweb’, a single piece of soft rubber with rectangular perforations exposing the Boost midsole. Scores of rounded rubber nubs jut out of its surface, and they grip tenaciously at first.
But there’s a catch; the traction is amazing on asphalt only when new. As time and miles go by, the initial euphoria fades away, along with the lugs getting shredded down to their stubs.
After just thirty miles, most will see the pointy bits completely wear down to their base around the footstrike area, which in our case happened to be the rearfoot. And if you’re forefoot striking, expect accelerated wear in the front. Even if you’re just using the forefoot as a transition area before toeing off, rapid wear still happens, as pictured above.
Based on our experience with many shoes, the rate of wear should subside once the nubs are fairly worn off and the outsole flattens out. But this rate of inital wear is completely unacceptable; why not make the outsole flat to begin with, then? While on topic, the Sprintweb outsole is no match for Continental or Adiwear rubber’s durability, and shoes like the Energy or Glide Boost will last much, much longer.
All that behind us, the most important question is – how does the Ultra Boost ride? Considering that the Boost foam is pretty standard as far as its cushioning behavior is concerned, does this $180 shoe do anything special which the $160 Energy or $130 Glide won’t?
The Ultra’s closest living relative is the Energy Boost 2, so we think that is a good reference to benchmark our ride experience against. We have quite a few thoughts to share with respect to how the Ultra performs, and perhaps the best way to articulate that is to break it down into three chunks – cushioning character, transition, and stability.
The Ultra Boost is soft, much more than lesser Boost models such as the Glide. The heel softness is comparable to the Energy Boost 2 , but with one major difference – the midsole is far more responsive. That is caused by two factors. If you were to look at the midsole heel top down, you will notice that a good portion of the Boost foam sticks outwards, along with the outsole lip.
This is true even for the medial and lateral side of the heel, where the lower section of the Boost midsole spreads out wider. Secondly, a wider flare on lower midsole creates a greater contrast with the upper portion, which then becomes relatively narrower. In short, this was the case on the Energy Boost 2 too, but on the Ultra, this design aspect is accentuated.
We also noticed that the upper half of Ultra’s Boost foam midsole has a smooth texture, compared to a faint ribbing running over the lower section. Could not tell whether this makes a difference on cushioning, but just know that the Energy Boost’s midsole had ribbing going over the entire midsole.
So with the extra foam sticking out and the midsole sculpting built in, a couple of things happen on rear-foot strike – a textbook example of cause and effect. Since there’s more Boost foam available for footstrike, the landing causes the midsole to slightly flex outwards, increasing the springback levels. Secondly, because of the way how the narrow section of Boost is ridged over a wider base, there is a distinct pistoning effect. The effect which has the narrower foam sink in and come back out soon after weight moves forward.
In simple words, it just feels like you’re squishing a larger amount of molded Boost globules under your foot compared to any other Boost running shoe.
Under the heel area, the Energy Boost 2 feels softer than the Ultra, and we can think of two reasons why that is. The insole used on the EB-2 is much thicker than Ultra’s and that makes part of the ride feel softer. The other part at play here is the sheer stack height and midsole design of the Energy Boost.
At its thickest point, the midsole height is greater on the Energy than the Ultra, and by lacking a wider base, foot-strikes on the Energy feel a bit one-dimensional. Personally, we prefer the more dynamic or layered cushioning character of the Ultra Boost.
The Ultra retains the signature ride character of adidas’s much touted midsole foam, but with a few tweaks, it manages to deliver a slightly different take on the experience.
The thing to know about the Ultra Boost is that the front and rear part of the midsole work together as two separate halves. In the back, a very cushioned ride pampers your heel as explained in the cushioning breakout.
The landscape changes as the midsole tapers down to a thinner forefoot, where the focus changes to delivering a higher level of ground feel. It is still cushioned, yes, but a far cry from the last bus stop. The entire shoe nevers get firm anywhere – the perforated strobel and a similar soft rubber outsole allow the Boost foam to transition freely. And softly.
So the transition isn’t effortless, and that is one of the reasons why the Ultra Boost won’t cut it as a shoe for speed-work. It’s definitely a shoe you can do training runs in, with distance no object. If you really need a fast shoe, better to have a pair of Boston 5 Boost to rotate with this fella.
Last but not the least, is the topic of how the Ultra does on stability. The upper might be firmly anchored to a rigid midfoot cage and heel counter, but the midsole does not have the rim which forms a part of models such as the Glide and Energy Boost.
So the Ultra’s ride is a little more bouncy, and more susceptible to encouraging inward foot-roll. The scooped midsole (the part which pistons) helps with maintaining support, but it still feels a bit wobbly compared to Boost shoes constructed with midsole rims.
But at the same time, we have to remember that the Ultra Boost is very much a neutral shoe, and the midsole behavior is well within the boundaries of that. No harm done here, this shoe is no Pure Boost.
After having looked at the Ultra Boost from multiple wear-test angles, our opinion is as follows: The shoe has many things working for it, like the signature ride which is part of the Boost platform, an upper fit which feels snug yet comfortable, and transition quality which feels great for a shoe this cushioned. Yet areas like premature outsole wear, a squashy toe-box and the unwanted pressure from the midfoot cage make a dent in the German brand’s ‘greatest running shoe’ claim.
It is certainly better than the Energy Boost (except for the outsole durability part), that’s for sure. But then, one has to pay $180 for a fresh box of Ultra’s and that sets the bar very, very high. Anyone would expect a truly exceptional product under the circumstances, and we feel that the Ultra Boost still has some ground to cover before it can honestly be called great.
(Disclaimer: For this review, Solereview bought the shoe at full US retail price.)