Asics Gel Nimbus 21 review: heavier than the Nike ZoomX Next%, but almost as fast

Gotta go fast? Feel like the blue hedgehog running with the Asics Gel Nimbus 21 super-fast running shoes

Asics Gel Nimbus 21 review
(Image credit: Future)
T3 Verdict

The Asics Gel Nimbus 21 is one crazy fast running shoe for neutral runners and it delivers speed and comfort on a whole different level. We wish it was a bit more stylish so it could be worn for something else than just running, but this is one for the purists.

Reasons to buy
  • +

    SERIOUSLY fast

  • +

    Comfortable and breathable

  • +

    Firm hold in midfoot area

Reasons to avoid
  • -

    Not much style going on

  • -

    If masses of support not speed is your thing, move on

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When a manufacturer claims that a running shoe is fast, I approach said shoes with caution. I mean, how can running shoes be fast? You are the one running in them, so surely, it is you running fast, not the shoes, right? The ASICS Gel Nimbus 21 would beg to differ.

If you are a neutral runner – meaning you land on the outer sole – the Asics Gel Nimbus 21 will most likely make you a faster runner. If we were to compare it with another running shoe, one that comes to mind is the silly-fast Nike ZoomX Vaporfly Next%. The ZoomX is way lighter than the Gel Nimbus 21 (6.6 oz and 10.9 oz respectively), but it feels almost as fast. 

The Gel Nimbus 21 has excellent energy return that will propel you forward like a cheetah when you run. Crazy as it sounds, you will find it difficult to hold it back.  

It also delivers this speed without compromise. Running a 10k feels like a breeze and at no point it feels like that the shoe is putting too much pressure on your feet. The Gel Nimbus 21 holds is just right; not too roomy and not too tight either.

No wonder the Asics Gel Nimbus 21 is in the second place on our best running shoes list. It would probably in the first place if it had a bit more style to it.  

The Gel Nimbus 21 follows the usual serious running shoes style guide (along with the likes of Brooks and Saucony) and just looks like any other running shoe on the market. No one will look at it twice, unfortunately so, because if they did, they'd see a brilliant running shoe with excellent cushioning.

Asics Gel Nimbus 21 review

Asics Gel Nimbus 21: high-tech shoes for long distance runners

(Image credit: Future)

Asics Gel Nimbus 21 review: the Tech

We haven't got enough space here to detail all the technology that went into the Gel Nimbus 21. It is PACKED with rocket tech that makes your runs more responsive and comfortable.

The Impact Guidance System (I.G.S) helps your heel-to-toe transition and transforms your impact force into forward propulsion. The I.G.S divides the gait cycle into three stages: contact, midstance and  propulsion, and puts technology in pace so that the conversion between stages are smooth and energy is forwarded accordingly.

The famous GEL cushioning in the rear and the front of the shoes reduce impact shock and and makes you bounce off the ground as you move forward.

The midsole has been outfitted with Asics' very own Flytefoam technology. This lightweight foam formulation has a special high-energy return elastomer helping to put a spring in your step.

Even the insole was designed for a better bounce: the SpEVA technology adds a bit more oomph to your step. To balance all the bounce, the Trussic system, located just under the midfoot, provides more stability by preventing twisting.

Asics Gel Nimbus 21 review

The Gel Nimbus 21 feels ergonomic and well-cushioned

(Image credit: Future)

Asics Gel Nimbus 21 review: the Ergonomics

Without a doubt, the Gel Nimbus 21 delivers a comfortable running experience, thanks to all the high-tech cushioning all over your feet. The Jacquard mesh upper is highly breathable and even after a few miles down the line, you won't feel any rubbing (unlike running in the otherwise brill Nike Joyride Flyknit), nor will be there much moisture, all wicked away through the mesh. 

Once you slipped into the shoes, you'll instantly feel the GEL areas on the sole, and not in a bad way. They feel like those retrofit gel-insoles you place in really uncomfortable shoes, but in the Gel Nimbus 21, they are there add even more comfort.

The Gel Nimbus 21 is still not as soft and bouncy as the pre-19 Nimbus era shoes, but in return it is definitely more responsive. The sole is definitely not as hard as the On Cloudswift's Helion. 

The toebox is spacious enough so your feet won't feel squashed (something that's been an issue with the last few iterations of the Gel Nimbus). The shoes curl back around your feet and hold them in hard turns, providing a secure feel, even if you run on uneven surfaces.

The lacing holds the midfoot area firmly but doesn't suffocate your bridge at all.

Asics Gel Nimbus 21 review

The all black colourway makes the Gel Nimbus even more featureless

(Image credit: Future)

Asics Gel Nimbus 21 review: the Aesthetics

Where the Asics Gel Nimbus 21 lacks the most is the visuals. It just hasn't got much of a character to it. Don't get me wrong: it is not a fashion shoe. Not all shoes have to pop and have the most eye catching aesthetics going for them.

That being said, in a saturated market like running shoes, you can't just rely on tradition and running dynamics, due the fierce competition, you have to deliver in every segment in order to stand out. You don't have to design the most handsome shoes, but you have to add at least some detail that will make the shoes a bit more memorable.

The tested Black/Dark grey colourway is literally as plain vanilla as it gets, a step up from the looks of any no-name Chinese brand. The Asics logo is well recognised among runners, anyone else will just think it's just a funny looking hashtag. Take the logo away, and there isn't really anything else to look at the shoes.

I personally like the contour of the Jacquard mesh upper contrasted against the wider, light-coloured sole looking down from above, but it is a view not many people will appreciate, apart from of course people wearing the shoes.

Asics Gel Nimbus 21 review

Japanese precision applied to running

(Image credit: Future)

Asics Gel Nimbus 21 review: the verdict

The Asics Gel Nimbus 21 is a comfortable and fast running shoe.

Compared to the Nike ZoomX Vaporfly Next%, it is heavier and admittedly less attractive-looking, but on the upside, the Gel Nimbus 21 delivers a speed that matches the ZoomX for a much lower price tag.

The I.P.S system will make sure you land softly and leave the ground in an explosive fashion. During the tests, the biggest issue with the shoes were slowing them down; the lack of control over speed can result in higher heart rates and therefore tire you out sooner. As soon as you get comfortable with the Gel Nimbus 21, though, switching from jog to run will be as easy as pie.

The strategically positioned GEL-areas provide cushioning in all the right areas, all the while the Flytefoam midsole gives firmness and responsiveness to the shoes.

The Jacquard upper mesh is breathable and leaves ample amount of space in the toebox, a definite improvement since the last iteration of the Gel Nimbus. The Gel Nimbus 21 doesn't hold your feet, it surrounds it from all angles and supports it in all the key areas.

One area it definitely lacks is aesthetics; there isn't much going on visually and most people won't look twice at the Gel Nimbus 21.

All that being said, if you want a cushioned, firm but not uncomfortable, and – above all – fast running shoe, the Asics Gel Nimbus 21 is just the right choice for you. If you need a running shoe purely for an excellent running experience, you won't be disappointed with these running shoes. On the contrary.

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Matt Kollat
Section Editor | Active

Matt Kollat is a journalist and content creator who works for and its magazine counterpart as an Active Editor. His areas of expertise include wearables, drones, fitness equipment, nutrition and outdoor gear. He joined T3 in 2019. His byline appears in several publications, including Techradar and Fit&Well, and more. Matt also collaborated with other content creators (e.g. Garage Gym Reviews) and judged many awards, such as the European Specialist Sports Nutrition Alliance's ESSNawards. When he isn't working out, running or cycling, you'll find him roaming the countryside and trying out new podcasting and content creation equipment.