Sunday, December 31, 2023

361° Karios 2 Review: 6 Comparisons

Article by Jeff Beck

361° Karios 2 ($140)


The Kairos 2 is an “inherent stability” trainer. By inherent we mean that instead of firmer foam posts or plastic support pieces it relies on its platform width, geometry and outsole rubber for its stability and support. It sits in the rapidly emerging more inherent stability category with shoes such as the ASICS Gel-Kayano 30  and Nimbus 26 and Puma ForeverRun Nitro compared at the end of the review.

It has 361’s excellent lively Engage TPE foam which we first experienced in the more neutral but still quite stable Centauri late in 2022 (RTR Review)


Comfortable upper holds the foot well, nice toe box width: Jeff

Subtle stability might as well be neutral: Jeff

Midsole has plenty of give without going mushy: Jeff

Runs lighter than the scale would say: Jeff

Soft rubber of the outsole is very grippy: Jeff 


Weight on scale will scare weight conscious runners off: Jeff

Somewhat pedestrian ride: Jeff

Tongue is a little short: Jeff


Weight: men's 10.7 oz  / 303 g (US9)  /  women's 9.5 oz / 269 g (US8)

  Samples: men’s 12.13 oz / 344g US 10.5D,  oz / g US

Stack Height: men’s 38mm heel / 30mm forefoot ( 8mm drop spec) 

Platform Width: 102 mm heel / 88 mm midfoot / 123 mm forefoot

$140  Available 2/1/2024

First Impressions, Fit and Upper

Jeff: The Kairos 2 is one of those shoes that don’t look overly big in any way, but is really a massive shoe in about every way. Its proportions work to make it look like your standard daily trainer, but with a 38mm heel stack, there’s so much shoe coming out of the box. Aesthetically they aren’t the most striking shoe, but not every car gets to be a Ferrari.

The fit is very generous widthwise, with a robust platform that sets a wide stage with the upper far from restrictive. The upper is made from recycled yarn, like several other 361 shoes,with 70% recycled materials, primarily plastic water bottles. 

The upper isn’t quite luxurious and plush as some others on the market, but it is very soft and the toebox space is incredibly ample for a shoe not made by Topo or Altra. 

Because it’s a road shoe there’s not much in the way of overlays to give extra support, and the toe bumper is near non-existent. 

The heel counter is pretty solid as well, while it isn’t bulky and is all interior build up, there’s not much give to it and it even includes some exterior TPU type strapping , which is to be expected as part of their stability line. 

The tongue is gusseted with thin nylon supports on each side, and the thickness is just enough to prevent lace bite, but again, not what I’d term as “plush”. While I like the texture of the top of the tongue (say that five times fast), the tongue ends a few mm shorter than it probably should. I didn’t have any issues, but could see some runners having some rubbing issues because of the tongue depth.

Midsole & Platform

Jeff: The midsole is made from 361’s Engage Foam, which is my second shoe with Engage, the first being the Futura trail shoe. It is is a gigantic slab of TPE foam. Durability seems very good, the TPE compound is dense without feeling overly heavy. It is the same foam as the most recent 361 Centauri.

As a neutral runner who supinates, I appreciate the more subtle approach to stability 361 has gone with. With a wide and stable platform runners get stability and support if they need it, but nothing overt if they don’t need the added stability. And it is a very broad platform front and back  of about as wide as it gets 123mm at the forefoot, a relatively svelte 88 mm at the midfoot and broad 102mm at the heel so between the ASICS GEL-Nimbus 26 and Kayano 30 


It’s hard to encapsulate the feel of a midsole, especially one that’s 38mm thick and also stable, but I’d say it’s a soft firm. Longtime runners may remember for years Mizuno was incredibly firm in everything they did, this could compare to a very soft Mizuno. It’s not a hard landing shoe, but it also isn’t pillow soft either. And it’s well balanced, with the forefoot and heel both feeling well cushioned.

Considering how thick the midsole is, there’s a surprising amount of flex under foot. You won’t confuse it with anything from the Nike Free line, but it also isn’t anything like the Saucony Endorphin Shift.


Jeff: The outsole rubber doesn’t have any identifying marks. It is soft and is pretty grippy. There’s a large slab of rubber covering the midfoot forward on the medial side (helping with stability)  with a small gap toward the lateral side, with the heel having two separate pieces of rubber, leaving a small gap of exposed midsole in the center of the heel as well as near the back of the midfoot on the lateral side. Much like the overall shoe’s performance, the outsole works very well. The medial heel rubber patch feels slightly firmer than the other two pieces, clearly contributing to the shoe’s inherent stability.

Ride, Conclusions and Recommendations

Jeff: The Kairos 2’s ride has a nice, but subtle, bounce to it. It’s far from the quickest shoe around, but as a stability focused daily trainer, that’s not what you’re likely looking for. The bounce is enough to make the ride feel modern, without losing control of your stride at any point. It’s a deceptive shoe, because it has width and cushioning that would make the early Hoka Bondi’s jealous, but because it’s large in every dimension no single aspect looks very wide or very cushioned, despite being incredibly generous in every way. And all of that volume means that weight has to be a concern - unless they used a flimsy midsole that wouldn’t hold up to hundreds of miles of daily training. 

Ultimately the Kairos 2 really doesn’t get anything wrong, the upper, midsole, and outsole are all independently very good components, and the result is a rock solid daily trainer. It’s not going to move the mercury in the hype department, but I’d imagine stability runners are used to that. But for $140 you’re getting a shoe that’s going to hold up over hundreds of miles, and while it might not have runners leaping for joy, it will give most stability runners a decent smile.

Jeff’s Score: 8.6/10

Ride (50%): 8 Fit (30%): 9 Value (15%): 10 Style (5%): 8  


6 Comparisons

Index to all RTR reviews: HERE

361 Centauri (RTR Review)

The Centauri has the same Engage foam sitting on a 36 mm heel (measured) / 27mm forefoot (9mm spec drop) platform so slightly lower than the Karios 2 at 38mm heel / 30mm forefoot ( 8mm drop spec). Its platform is 10mm narrower at the heel and forefoot and 5mm narrower at the midfoot. It has less medial rubber for stability but is still a stable ride but a more neutral one than Karios.

361 Spire 5 (RTR Review)

Jeff: The more neutral focused Spire has a very similar fit upper to the Kairos, but under foot the Kairos is substantially wider, making the inherent stability stick out. The Spire has a similar but different TPE midsole that’s softer and bouncier, although the narrow platform is more noticeable than the compound difference - not to mention the extra 5-6mm of stack height. 

ASICS GEL-Kayano 28/29 (RTR Review)

Jeff: It’s been a few years since I ran in the Kayano 28, but it’s stability elements are much more pronounced. The recent versions seem to have streamlined things, similar to the Kairos’ inherent stability philosophy. The 361 midsole is much more lively, and absorbs the ground much better, while also boasting a wider toebox.

ASICS GEL-Nimbus 25/26 (RTR Review)

Jeff: Not many shoes can make the Kairos look and feel lacking, but the Nimbus 26 and its immense heft does exactly that. It’s only a few mm, but you can feel the difference, especially since the ASICS is so much softer underfoot. The Nimbus isn’t nearly as stable, so if you need lots of stability I’d still lean toward to the Kairos over the Nimbus, and the Kairos also has a wider toebox than the Nimbus. But if you only need a little stability and toebox width isn’t a huge concern, definitely give the Nimbus a shot as well.

Puma ForeverRun Nitro (RTR Review)

Jeff: One of the most surprising shoes I’ve ever run in - it was the first stability-centric shoes that’s actually fun to run in. While it doesn’t have nearly the massive stack of foam the Kairos does, it’s still well cushioned, though much more narrow in every part of the foot than the 361. I favor both the Puma midsole and outsole materials, but the extra stack height of the 361 nullifies the material advantage of the ForeverRun Nitro.

Nike ReactX Infinity Run 4 (RTR Review)

Jeff: Nike’s subtle stability shoe got a new flavor of React midsole foam for the 4th iteration, and it softened things up quite a bit from the stale React that had celebrated quite a few birthdays. While it has a similar stack height on paper, the Nike feels much more cushioned in the heel, and much less cushioned in the forefoot. It’s also much softer, I’d even say it’s borderline mushy, while not feeling all that stable.

The Karios 2 releases January in speciality run retail stores and more broadly February 2024.and

Samples were provided at no charge for review purposes. RoadTrail Run has affiliate partnerships and may earn commission on products purchased via shopping links in this article. These partnerships do not influence our editorial content. The opinions herein are entirely the authors'.

Comments and Questions Welcome Below! Please let us know mileage, paces, race distances, and current preferred shoes

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