Adidas Ultraboost 5X ($180)

Introduction

The Ultraboost 5X is a brand new take on the UB focused first and foremost on running performance. Well known for its iconic styling, Boost midsoles, knit uppers, plastic midfoot cages and underfoot plastics this new UB loses the cage and simplifies the midfoot plastic support to a tried and true X shaped Torsion system. Adi “boosts” the Light Boost 9mm front and back and still loses about 0.5 oz / 14g in weight to come in about 9.85 oz / in a US9. 

That is light for its big 39 mm heel / 29mm forefoot stack height and full combination Continental and crystal type rubber outsole. It is about 1 oz / 30g lighter than what I see as its closest competitor the slightly lower stack height Saucony Triumph 22 while sitting on the same width 95 mm heel / 75 mm midfoot / 115 mm forefoot platform. 

The result is yet another 2024 hit from adidas in its long neglected everyday running category. It joins the lighter and livelier Adizero SL 2 (RTR Review) and slightly lower stack height and somewhat more stability focused Supernova Prima (RTR Review).

By freeing Boost Light foam from its prior cages, adding more of it while losing weight, adidas has “boosted” the energy level of the ride at any pace while increasing cushion and comfort. Please read on for my impressions after a first faster 6 mile run today.

Pros:

• Highly energetic pleasing ride- Boost Light foam shines!  - Sam, Jeff
• Consistent feel and cushion at all paces - Sam, Jeff
• Versatile; pretty much any pace or distance run except short tempo or intervals.
• Well held for a stretch knit upper
• Tenacious and noticeable Continental traction even on dry roads. Expect great durablity. - Sam, Jeff

Cons:

• Time to rethink the knit upper: stretch knit upper adds weight, requires thick overlays and underlays and a plastic clip, doesn’t quite keep up with the far higher performance platform underfoot. - Sam, Jeff
• Higher end pricing for a trainer- Sam, Jeff
• Loose knit doesn’t make for a secure hold - Jeff

Most comparable shoes 

Saucony Triumph 22 (RTR Review)

361 Eleos (RTR Review)

Supernova Prima (RTR Review)

Nike Pegasus 41 (RTR Review)

Ultraboost Light (RTR Review)

Stats

Approx. Weight: men's 9.85 oz / 279g

Prior Version Weight:  men’s oz /  g

  Sample Weight: men’s  9.62 oz / 273g US ,  10.26 oz / 291g US10.5

Stack Height: men’s 39 mm heel /  29 mm forefoot ( 10mm drop) 

Platform Width: 95 mm heel / 75 mm midfoot / 115 mm forefoot 

First Impressions, Fit and Upper

Sam: Classic Ultraboost styling, modernized and streamlined. Gone are the bulbous lines, plastic cages, and showy underfoot plastics of the 2023 Ultraboost Light (RTR Review).  A stunning clean and striking design.

Without visually appearing to be so, up goes the stack height of Light Boost by 9mm and down goes the weight by about 0.5 oz / 14g. 

The upper is the customary stretch Primeknit. I believe seen on Ultraboost since day one.

It is a most comfortable upper as in lieu of the infamous cage the midfoot is held on both sides by thick “3 Stripes” overlays which, by the way, are highly reflective. And that is not all as inside we have laminated underlays at midfoot. All to keep the stretch in check when actually running..and that is what 5X is focused first and foremost on.

The tongue is a decently thick unpadded stretch knit. For a knit upper midfoot hold is adequate for my medium to low volume feet with the lace up easy and secure. .  

The heel and collars are well padded with not only pillow type pads but a molded padded achilles and far rear of the shoe which is quite pliable. To support the foot at the rear, a plastic clip surrounds the heel area rising on both sides. Comfortable with good hold.

The toe box is not super broad, or high, but the knit stretches, more vertically in the center than at the sides and toe bumper where the knit is denser for support. The toe bumper is pliable.

As often customary with Ultraboost, the silhouette is “long” I have a full thumb and a bit of front space which. given the low very front of the shoe, is correct and presents no problems. I was true to size for my low to medium volume feet. Very narrow low volume feet might consider sizing down half a size. 

While a fine Primeknit upper. and the best yet for an Ultraboost for me, I think it is time to reimagine the upper and materials as it does not quite keep up with the new much higher actual run performance profile of the overall platform underfoot. 

Jeff: I agree with Sam on a number of items. Bulbous is absolutely the best way to describe the previous version, and even though it was called the Ultraboost Light, it wasn’t all that light, especially considering how thin the forefoot felt. First impressions are a substantial performance improvement, and while they stuck with the Ultraboost’s longtime formula of comfort, as a running shoe there aren’t caveats like we’ve had in the past. There’s no need to try to qualify it, this is an actual honest-to-goodness running shoe. 

I’m with him that the upper is made from a comfortable knit, but I’ve found it has stretched quite a bit. I’ve only put about 30 miles on them, and I already can’t get a dialed in fit leading to several minor ankle rolls. It’s not an inherently unstable shoe, but the upper feels much more casual focused. If they’d have gone with the midfoot cage I’m not sure if it would perform better. That stretchy upper does make the adequate width toebox effectively even wider, but it doesn’t hold the foot that well (which is why I’m not confident a built up midfoot cage would help).

The only part I’d disagree with Sam is the sizing of this model. In the past the length did seem off, but this time around the length seems accurate - my standard size 10.5 gives about a thumb’s width from my largest toe. That said, he’s spot on about narrow footed runners likely needing to size down.

Midsole & Platform

Sam: Unlike recent Ultraboosts,  the star of the show here is not the styling or added underfoot plastics but the Light Boost midsole foam and lots more of it, 9mm more front and back to come in at a max heel of 39mm and forefoot of 29 mm. The prior Ultraboost with Light Boost felt “thin” and firm upfront not only due to less foam height but due to its more extensive plastics above the outsole as shown below.

To put it politely, it was a quite rough front ride. 

Not so here!  To stabilize the midfoot for those that land there and move the transitions along, and they are easy and smooth at any pace, adidas goes with an X shaped yellow Torsion System. 

Torsion is proven and I find effective. We also get a flex point at the ends of the X and a lively somewhat bouncy toe off which is stabilized by the full front rubber coverage.

Heel landings are smooth with lots of energetic rebound with the transition well decoupled even though there is no deep decoupling groove. Quite different from the Supernova Rise where the similar design heel felt firmer, stiffer and harder to roll off of. 

This midsole is big smiles for me. The Light Boost foam is more pulled together and is less bouncy soft as old Boost was, requiring EVA layers to keep it under control and stable. Here the feeling is of lots of “energy” returned but never in a wild manner yet which is also nonetheless super fun in feel. 

Adidas did a great job balancing a ‘pure” all foam experience with enough stability from the broad platform, X Torsion System and especially the outsole which provides plenty of response. 

Compared to adidas new Dreamstirke+ supercritical foam in the Prima and Rise, the Light Boost feels a touch softer and bouncier. a bit slower to return, maybe less dense but yet more pleasing.  Light Boost feels closest to Saucony’s PWRRUN Pb in the new Triumph 22 but with a more effective overall “drive train” given Torsion and outsole design and is less ponderous and lighter.