The second-generation Adidas Prime X 2 Strung is a carbon running shoe designed for chasing fast times across a range of distances…

This shoe packs a particular set of skills for conquering marathons and half marathons. The first Strung was exciting, lively and a fantastic rival to the record-breaking Nike Alphafly Next 2. But with a slew of significant changes, is the X 2 Strung an upgrade and how does it stack up against the carbon shoe competition? sent Kieran Alger a pair to find out…

Adidas Prime X 2 Strung


  • Fast, energetic, energy-saving
  • Good, cushioned protection


  • Lacks stability
  • Heavy for a carbon race shoe
  • Narrow ‘booty’ fit is a struggle for wider feet

Speed: 5/5
Stability: 2.5/5
Comfort: 3.5/5

Materials STRUNG upper; Textile lining; Lightstrike Pro cushioning; Continental™ Rubber outsole
Weight 10.4oz (size 11 US)
Colours Lucid Lemon / Core Black / Arctic Night
Heel-toe drop 6.5mm

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Adidas Prime X 2 Strung

That mesh upper is made from at least 50% recycled material

Adidas Prime X 2 Strung design: what’s new?

This shoe now packs an even bigger three-layer stack of Adidas’ light and responsive Lightstrike Pro midsole foam, which takes the already whopping heel-toe stack from 49.5mm up to 50mm. That’s very much not race legal, but unless you’re elite that probably doesn’t matter.

There’s also a new double carbon plate system and a significantly lower 6.5mm drop thanks to that extra wedge of foam under the forefoot.

Up top, there are new booty-style uppers. They still use the innovative Strung tech we saw in the first gen, with strategically placed strands building out the shoe’s support where it’s needed most. The heel collars are still stripped back and minimal, with just a couple of small foam pads to hold the heel.

Flip them over and you get the same covering of Continental rubber in the forefoot, to provide the grip and outsole protection in the forefoot with a couple of strategic pads reinforcing the heel.

Unfortunately that bigger stack means the Prime X 2 Strung is now a chunk heavier, weighing in at 11.6oz / 330g in my test UK 8.5. That’s hefty for a carbon running shoe. In fact, it’s the heaviest super shoe going. The Nike Alphafly Next 2 weighs just 8.7oz / 248g, the Saucony Endorphin Elite is 7.5oz / 11g, while the Nike Vaporfly Next 3 tips the scales at 6.9 oz / 195g.

Adidas Prime X 2 Strung fit

If you’ve got wide feet and high insteps like me, the shift to the one-piece booty-style upper makes it a real struggle to get your feet into Prime X2 Strung. I basically need a shoe horn to squeeze my foot through the narrow opening.

But once they’re on, the fit is generally OK. The uppers hug relatively snug, as you’d expect from a race shoe. However, they’re not quite as secure and dialled in as I’d expect, and I found there was a bit of movement in the heel area that I couldn’t fix by fiddling with the lacing. It’s not loose but it’s not 100% secure either.

Despite that – and my struggles squeezing into them – I’d still recommend going true to size.

Adidas Prime X 2 Strung performance

I’ve done around 25 miles in these, including an all-out mile test and a 90-minute mixed-pace test. My runs were mostly on road with the odd river path thrown in to really test the stability.

Straight out the box, once you’re up on that huge stack of Lightstrike Pro foam, these feel racy, punchy, fast but notably wobbly. For the mile test, I clocked one of my fastest ever miles on pretty tired legs. Moving at all-out pace with a dialled-in form, you can feel the X 2 Strung delivering spring, energy and efficiency.

On the 90-minute run test, I mixed up the miles between 10km, half and marathon pace, along with some slower miles to see how protective the Strung are when you rock back a bit.

The stability wasn’t world-beating, but you wouldn’t necessarily expect it to be on a massive superfoam stack. In my tests, though, I found the X 2 Strung even less stable than its predecessor.

You can feel that triple-layer of Lightstrike Pro extra foam under the ball of the foot as it works to roll you through each step, but that brings a lot of lateral movement. You really have to focus on foot placement to control these wild shoes. I nearly rolled my ankle twice in testing.

They also don’t cope too well in the corners, and I often felt my foot sliding off the base. This happened with the original Strung, too, but because there’s less foothold security, it somehow feels more pronounced in the Prime X 2 Strung.

That said, when you concentrate on landing with precision, these are still excellent. They’re incredibly springy, lively, energetic and fast. It’s a big, bouncy, bounder of a shoe that’s a lot of fun to run in. They deliver a leg-sparing ride that gives back plenty in each step.

Unsurprisingly, I think the X 2 Strung performs best when you’re moving in your best form with real race intent, and though the lack of stability isn’t great, when you slow down on tired legs the big cushioned stack offers plenty of protection from the road and helps stave off the dreaded foot fatigue deeper into the longer runs. That’s a big win over some of the other more direct carbon shoes like the New Balance SC Elite or the HOKA Rocket X2, for example.

Adidas prime x 2 strung outsole

Continental rubber in the forefoot outsole provides grip and there are a couple of strategic pads reinforcing the heel

Is the Adidas Prime X 2 Strung a good shoe?

The Prime X 2 Strung is a bit more of a mixed bag than the first generation Prime X Strung.

I don’t think the upper change works. I much preferred having more control over the fit and lockdown. The bigger stack also makes an already comparatively unstable shoe even more so.

It’s definitely at its best for straight road urban city marathons. The extra weight potentially limits how some runners might use the shoe. It makes it a little less likely as a 5k shoe, for example.

But despite all of that, it’s a fun, wild, crazy-energy ride that definitely has marathon PB potential, on the right day, moving with the right intent. It’s got that energy sparing effect that you need with 6 miles to go in a marathon, same as the Alphafly and the original Strung.

The price hike in the UK is a bit frustrating, though in the US it stays the same, so that’s not an issue.

Like its predecessor, the Strung X 2 is definitely a shoe to rival the Nike Alphafly Next 2. If you’re not bothered about that illegal stack height, this is up there with the very best carbon racers over pretty much every distance – though it really excels on the big straight, flat roads of an urban city marathon or half marathon.

However, if you can find the first generation Strung for its original price or cheaper, I think it’s easily a match – if not better – than this version on many fronts.