Summary

We spent 8.5 hours reading reviews from experts and users. In summary, this is what runners think:

8 reasons to buy

  • Many of the testers appreciate the plushness of the Asics Gel Cumulus 21. 
  • It offers a responsive ride, expressed several runners. 
  • According to quite a few buyers, the running shoe has ample support. 
  • There are some purchasers who appreciate the durability of the shoe. 
  • The neutral running shoe is made of high-quality materials, hailed numerous reviewers. 
  • It has enough room for natural toe splay, commended multiple customers. 
  • Some commenters laud the snug wrap of the shoe around the foot. 
  • Various users admire the versatility of the running shoe.

4 reasons not to buy

  • A number of athletes dislike the bulk of the shoe. 
  • The outsole of the road running shoe is too stiff, remarked some wearers. 
  • Quite a few have observed that the shoe has mild tongue slippage. 
  • According to several experts, the road running shoe lacks breathability.

Bottom line

The Asics Gel Cumulus 21 is a performance running shoe that boasts unparalleled speed and comfort. It provides plush underfoot cushioning when worn during long-distance runs. Loaded with the brand's top-tier technologies, the road running shoe flaunts high-strength qualities and premium energy return. With its generous cushioning, foot protection is also amplified, preventing strain or injury. Overall, the design of the Gel Cumulus 21 does not compromise both style and function.

Tip: read our review of Asics Gel Cumulus 21, or see the best running shoes.

Facts

Rankings

A top rated Road running shoe
A top rated Asics running shoe
Top 8% most popular running shoes
It has never been more popular than this August
Better rated than the previous version Asics Gel Cumulus 20

Reviews from around the internet

Expert reviews:

User reviews:

Shoebacca, Sun and Ski and 14 other shops don't have user reviews

Video reviews and unboxing

  • The successor to the popular Asics running shoe, the Gel Cumulus 20, has now been made even better. The Asics Gel Cumulus 21 features an even more improved level of comfort and support by integrating Asics’ innovative technologies in this neutral running shoe that will cater to everything that any runner needs.
  • The Gel Cumulus 21 has now added the use of the FlyteFoam Propel technology.  This technology combines a lightweight foam formulation with a high-energy return elastomer for increased bounce and unparalleled toe-off that offers a better performance in every stride.
  • This 21st version of the Gel Cumulus also features the Impact Guidance System which combines interlinked sets of technical features that work together for more natural foot movements during the run.
  • Also found in this shoe is the more refined stretchable Jacquard mesh upper which has been modified for enhanced breathability, comfort, and fit. It now has enough perforations that allow efficient airflow, thus keeping the foot cool and dry.
  • The ComfortDry Sockliner is also incorporated in this shoe. It helps regulate the overall shoe temperature with its unique dual-layer cushioning system that combines the support of the base foam with the slow recovery foam for a more customized insole.
  • Even more updates to the Gel Cumulus 21 are showcased in the shoe’s midsole with the Rearfoot and Forefoot Gel cushioning system.  It is the technology responsible for the shoe’s premium shock absorption and cushioning.
  • And last but not least is the improved function of the FluidRide technology. This exceptional shoe tech is a weight reduced two-layered sole that gives the shoe its improved cushioning and incredible bounce.

The Gel Cumulus 21 comes in medium size D for men and medium size B for women. This neutral Asics road running shoe’s base fits those who have the standard medium sized heel. Also with the sizing of this shoe, going a half size higher than one’s actual size will ensure that the shoe will not be too tight when worn.

Similar to the well-known Asics Gel Quantum 180 4, the outsole of the Gel Cumulus 21 is made of the light AHAR sponge rubber outsole. The AHAR is an acronym for Asics High Abrasion Rubber, and it provides excellent abrasion resistance,  and traction. It is placed in critical areas of the outsole to provide exceptional durability.

Meanwhile, found in the shoe’s forefoot is the DuraSponge outsole material which is a blown AHAR rubber that enhances both the cushioning and durability in the forefoot. The DuraSponge also functions as a shock absorber throughout the run, making the ride more enjoyable than ever.

The midsole area of the Gel Cumulus 21 is packed with the most innovative Asics technology. It features the reduced weight FluidRide® which provides the right combination of bounce back, durability, and cushioning.

The shoe also uses the FLYTEFOAM™ Propel technology which is Asics’ energetic foam formulation that provides excellent bounce and energy return. This midsole technology is made of a unique elastomer compound that offers great responsiveness no matter the duration of the run.  It also utilizes organic super fibers that help lessen packing out the that usually happens with softer, low-density foams.

The use of Asics midsole technology continues with the SPEVA™ foam in the Gel Cumulus 21. The SPEVA™ foam is a spongy layer between the sole and upper designed to absorb shock and improve the shoe’s cushioning performance.

Also adding to the shoe’s midsole power is the I.G.S® or better known as the Impact Guidance System technology.  This midsole technology is based on Asics’ design philosophy which is they aim to complement and not change the natural movement of the legs and feet. It combines four different types of technology for the cleanest stride possible. An external heel counter minimizes ankle movement while Trusstic technology keeps your foot in place and aids in smoother landings. The Guidance Line technology also increases stability, and the DuoMax technology dynamically reduces stress and evens the foot plane.

Completing the Gel Cumulus 21’s technology-packed midsole are the Rearfoot GEL™ and the SoLyte Midsole. The Rearfoot GEL™ technology is responsible for attenuating the shock received during toe-off phases, while the SoLyte Midsole which also has a tough material called AHAR+ provides exceptional grip and helps improve the shoe’s durability and cushioning.

The Gel Cumulus 21 is now engineered with the stretchable Jacquard mesh upper which provides the shoe’s breathability, flexibility, and customized fit. The mesh’s elasticity is multidirectional, thus providing freedom of movement. It is also reinforced in strategic areas to offer more support to the shoe.

The shoe also has a reflectivity feature which contains reflective materials designed to enhance better visibility during low-light hours. This enhancement guarantees the runner’s safety while training at any time of the day.

Besides the use of the new jacquard mesh, the shoe’s upper is also covered with the ComfortDry.  It is an anti-bacterial material that creates a cooler, drier, and healthier shoe environment while running for long hours.

The shoe also features the Discrete Eyelets which are independently placed eyelets that aids in dispersing lace tension caused by tightened laces through a single eyelet.  With the use of the Discrete Eyelets, it creates a customized fit feeling resulting in better upper comfort.

Finally finishing off the shoe’s upper is the Seamless Construction,  it reduces the chances for irritation and friction brought by traditional stitches and seams.

Author
Jens Jakob Andersen
Jens Jakob Andersen

Jens Jakob is a fan of short distances with a 5K PR at 15:58 minutes. Based on 35 million race results, he's among the fastest 0.2% runners. Jens Jakob previously owned a running store, when he was also a competitive runner. His work is regularly featured in The New York Times, Washington Post, BBC and the likes as well as peer-reviewed journals. Finally, he has been a guest on +30 podcasts on running.

jens@runrepeat.com