We spent 6 hours reading reviews from experts and users. In summary, this is what runners think:

5 reasons to buy

  • The weight of the Asics Gel Cumulus 21 Knit is considered light enough for all-day use.
  • This running shoe apparently has a versatile construction that allows it to accommodate activities other than running.
  • Some users have mentioned that the midsole unit is responsive enough to welcome energized steps.
  • The upper unit is welcomed because it accommodates the natural bending and swelling of the foot as it runs.
  • Breathability is an aspect that has been appreciated due to the presence of the ventilation pores.

2 reasons not to buy

  • Some tearing has been observed near the forefoot section of the upper unit.
  • A restrictive midfoot section has caused some discomfort to a few users.

Bottom line

The overall reaction towards the Asics Gel Cumulus 21 Knit has been positive. This neutral running shoe is welcomed because of its versatile design. The midsole unit’s capacity to provide comfort and responsiveness is particularly highlighted. Conversely, the restrictive and not-so-durable upper is criticized.

Fans of road running shoes can have fun with the Gel Cumulus 21 Knit.


The Asics Gel Cumulus 21 Knit is quite similar to the base Gel Cumulus 21 model in many ways, but if one looks closely, the differences in the design are stark and deliberately unique. While the OG model featured a separate tongue unit, the Knit version has a one-piece opening that evokes a sock-like coverage. The knitted textile almost works exclusively to secure the foot, though there is scant use of printed overlays to reinforce the cover system. The same midsole and outsole components are featured in this product.

Runners can choose the sizes to which they are most accustomed because Asics utilized the standard sizing schemes when they made this product. Still, it is highly recommended to personally test this shoe and its interior environment to ensure comfort and form-welcoming length.

Fit-wise, the elements that work in tandem to deliver security and wobble-prevention are the stretchy and sock-like upper fabrics and the semi-curved shape of the platform. The natural curvature of the human foot is the basis of the overall design.

AHAR® or Asics High Abrasion Rubber is the material that is used for the external pad of the Asics Gel Cumulus 21 Knit. This compound is tasked with protecting the base of the midsole and its contact points from the abrasive nature of the surfaces. It also delivers traction, a trait that is fundamental to the quality of the run and the safety of the runner.

Forefoot flex grooves provide the platform with the capacity to bend along with the foot as it gears itself for the toe-off. Energized liftoffs are what serves as the end-point of these elements.

FlyteFoam® Lyte is used as the base midsole piece. The job of this layer is to absorb impact shock during the landing phase while also ensuring comfort throughout the running session. The lightweight construction helps to prevent any feeling of being weighed down by the shoe.

A FlyteFoam® Propel topsole is meant to offer a snappy performance and a refined forefoot lift. The somewhat stiff structure helps to energize the toe-offs while also encouraging a perception of balance whilst the foot is resting on top of the cushioning system.

GEL® is a shock-absorbing technology that is placed in both the forefoot and heel. This silicon-based feature prevents discomfort by mitigating the landing shock, thus causing a smooth heel-to-toe transition. GEL® is used in many Asics running shoe series, including the venerated Gel Nimbus line.

A knitted textile is used for the upper unit of the Gel Cumulus 21 Knit. The job of this element is to provide a form-fitting and seamless wrap. It has breathing pores for ventilation throughout the run.

Printed overlays cover the sides and the eyestays. These elements are thin yet able to help with the attainment of an agreeable foot-wrap.

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.