Good to know

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.


How Asics Gel Cumulus 21 Knit ranks compared to all other shoes
Bottom 18% road running shoes
All road running shoes
Bottom 18% Asics running shoes
All Asics running shoes
Bottom 19% neutral running shoes
All neutral running shoes


The current trend of Asics Gel Cumulus 21 Knit.
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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.