183 users: 4.3 / 5
1 experts: 95 / 100
Terrain: Road / Treadmill
Weight: Men 12.3oz / Women 10.2oz
Heel to toe drop: Men 10mm / Women 10mm
Arch support: Neutral

Verdict from 5.8 hours of research from the internet

7 reasons to buy

  • The Gel Cumulus 21 GTX is comfortable, according to many users. 
  • Several runners mentioned that the shoe is supportive. 
  • A few people highlighted the quality of materials used in the shoe. 
  • Many purchasers appreciated the shoe’s waterproof features. 
  • Some buyers said that it can keep the foot dry and cool for an extended period. 
  • It is perfect for long-distance runs, based on some reviews. 
  • A couple of users admired the lightweight structure of the shoe. 

2 reasons not to buy

  • The shoe is a bit narrow, said some commenters. 
  • A wearer complained that the outsole is not durable enough. 

Bottom line

Asics Gel Cumulus 21 GTX is a neutral running shoe that works for mild pronators or people who supinate. This waterproof running shoe is equipped with advanced features that aim to enhance comfort and running speed. It is specially designed for running on hard surfaces and keeping the foot dry and comfortable no matter how soggy the terrain.  

Tip: see the best running shoes.

Expert reviews:

User reviews:

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  • The Asics Gel Cumulus 21 GTX is the waterproof version of the Asics Gel Cumulus 21. This running shoe possessed technical features that are designed to provide maximum support and cushioning to the foot over long distances. 
  • The Gore-Tex® fabric is incorporated in the upper unit of the Gel Cumulus 21 GTX. This fabric is responsible for making the shoe waterproof and breathable. It provides reliable protection during extreme weather conditions. 
  • The Gel Cumulus 21 GTX is also designed with a higher toe box, providing enough room for natural foot movements. 
  • Other notable updates in the Gel Cumulus 21 GTX are the inclusion of extra foam in the heel collar and new groves in the outsole unit. 

Featuring the removable sockliner and lace-up closure, the Asics Gel Cumulus 21 GTX guarantees a comfortable in-shoe feel. This running gear utilizes the standard sizing measurement, although it is advisable to test the shoe first to ensure a perfect fit. 

The Asics High Abrasion Rubber (AHAR®) outsole is incorporated in the Gel Cumulus 21 GTX. This material is composed of carbon rubber that is also used for car tires. The AHAR® material is positioned in critical areas of the outsole unit to enhance the platform’s durability. The AHAR® outsole is also featured in other Asics running shoes like the Asics Gel Venture 7 and Asics Gel Quantum 360.

The new grooves under the heel allow for a softer landing. They also help improve the outsole’s gripping performance.

The I.G.S® (Impact Guidance System) technology combines the interlinked sets of the shoe’s technical features to function together, enhancing the foot’s natural gait from heel-strike to toe-off. 

A lightweight foam construction called the Flytefoam® Propel technology in the midsole unit provides high energy return. This material delivers a softer and bouncier running experience. 

Providing supreme cushioning is Flytefoam® Lyte technology. This component ensures a lightweight running feel without sacrificing durability. 

The Asics' Guidance Line™ is integrated into the shoe to help enhance gait efficiency. This component is designed to guide the foot while running to maintain balance and consistency. 

The RearFoot and ForeFoot Gel® cushioning helps to minimize shock caused by impacts. This cushioning system helps prevent muscle strain and other injuries.  

This road running shoe also comes with a removable sockliner for additional comfort.

The Gore-Tex® fabric used in the upper is responsible for making the shoe waterproof and breathable. This component shields the foot during extreme weather conditions. It effectively keeps the water out of the shoe while allowing the heat to escape, providing enough ventilation to keep the foot cool and dry. 

To allow for natural foot movements, the designers have added more height in the toe box. This provides enough room for a more accommodated forefoot fit. 

The seamless upper construction helps prevent irritation while the Personal Heel Fit in the heel collar provides a more customized in-shoe feel and additional comfort. Additionally, the lace-up closure allows the user to control the tightness or looseness over different sections of the shoe. 

The reflective details on the upper provide additional protection by allowing the user to remain visible even in the dark. 

Size and fit

True to size based on 37 user votes
Small (22%)
True to size (70%)
Large (8%)
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Same sizing as Asics Gel Cumulus 18 GTX.

Calculate size

Forefoot fit
Narrow Wide
Heel fit
Narrow Wide
Tight Roomy

How Gel Cumulus 21 GTX compares

This shoe: 92
All shoes average: 86
58 99
This shoe: $130
All shoes average: $119
$40 $350
This shoe: 12.3oz
All shoes average: 9.5oz
3.5oz 16.2oz
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.