Preface
Last September, Codoon launched its first generation of smart running shoes, the 21K, which received an enthusiastic response and sold out quickly during the crowdfunding phase on JD.com. It also won the 'Top Ten National Running Shoes' award at the China Marathon Expo. I had the privilege of reviewing the first generation 21K; the shoes were good but not suitable for me.
After more than six months of collecting feedback and optimization,
This summer, Codoon released the upgraded second generation of smart running shoes, the 21K, which features many innovations compared to the old model.
The company even conducted a crusher experiment to test the cushioning performance of the second generation 21K!
Crusher Challenge for Codoon Second Generation 21K
Unboxing Overview
Codoon Green
First of all, the packaging does not use the previous quick-release zipper original color box. The second generation 21K's packaging box is similar to most shoe companies, using a regular shoe box to reduce costs and benefit more runners.
Overall, the workmanship is excellent, with even stitching, comparable to international brands.
The most noticeable difference is that it is much lighter than the previous generation. I weighed a size 42 at 283 grams, while the official website states 240 grams, which I assume is for the smallest size.
Men's size 42 weighs 283 grams per shoe.
The anti-collision toe is more upturned and the shoe last is narrower than the first generation. The upturned anti-collision toe reduces rolling resistance, and the narrower shoe last provides a tighter fit.
The shoe upper is different from the common sandwich upper. The 21K uses a double-layer breathable upper. When I tried it on, the breathability was acceptable, but I hope the next generation 21K will improve this aspect.
The printed lines on both sides of the shoe provide support and wrapping.
The double-stitched heel fits better, and the TPU support piece in the heel enhances wrapping performance while also stabilizing running posture. The R-21K uses reflective material, making night running safer.
This time, the 21K uses the American ORTHOLITE high-elastic insole. The biggest advantage of the ORTHOLITE high-elastic insole is its excellent rebound and sweat-absorbing performance. I tested it in temperatures over 30 degrees Celsius, and my feet remained dry after a half marathon. This insole adds a lot of points to the 21K.
The insole is 5mm thick at the forefoot and heel.
The midsole is a crucial indicator of whether a pair of running shoes is truly exceptional. The 21K uses a DUO-HEE elastic midsole, which has good rebound. Combined with the ORTHOLITE high-elastic insole, the on-foot feel is soft and bouncy, giving you the sensation of stepping on clouds!
DUO-HEE elastic midsole
The GEL energy-absorbing cushioning gel in the outer heel provides protection against overpronation.
The EVA cushioning outsole is somewhat innovative. The forefoot and heel outsoles use a segmented cushioning design. This is easy to understand: the heel, which bears more weight, has a harder outsole, while the forefoot, which aids in propulsion, has a lighter and more elastic outsole.
The heel outsole is denser and harder than the forefoot.
The forefoot outsole is light and elastic.
The smart chip is located under the insole of the left shoe. Compared to the first generation, this generation's smart chip has been significantly optimized and is more intelligent. The first-generation chip was not smart enough and did not record accurately. For example, it would start recording distance and steps as soon as you put on the shoes, including warm-up time, which would lower the pace and step frequency, making the data almost useless.
The second-generation chip is much smarter. It does not include warm-up time in the total exercise distance. Moreover, if you pause for a long time, it will automatically upload the data. For example, if you run for 5 minutes, take photos for 2 hours, and then continue running, it will record it as two separate activities. So don't stay in one place for too long. My half marathon was recorded as two activities because I took too long taking photos!
As shown in the picture below
The 21K's smart chip can analyze simple running dynamics such as stride length, step frequency, forefoot and heel landing, ground contact time, and impact force.
With intelligent scoring and voice systems, the 21K can conduct fitness tests and provide online training from beginner to marathon levels.
Performance Test
Before running, my biggest concern was foot heat. The heel padding and tongue are thick, and the breathable mesh is not very large. Moreover, it's midsummer, and the static feel was quite stuffy, especially outdoors, like stepping on two fire wheels! However, after running a half marathon, my feet were surprisingly dry. Although there was still a sense of heat, it was not stuffy. I think this is thanks to the ORTHOLITE insole!
Running on the track, in a word, it is soft and bouncy, suitable for most runners. However, for speed running, the forefoot is too soft and lacks power.
Performance on the road is good, with moderate softness and hardness to reduce ground impact. The high-rebound DUO-HEE midsole provides direct power and reduces ground contact time, unlike some running shoes that lack rebound and make you feel like you're sinking with each step!
Summary of Pros and Cons
Pros: Compared to the old model, it is lighter. The DUO-HEE elastic midsole and EVA cushioning outsole are very bouncy. The ORTHOLITE high-elastic insole adds a lot of points to this 21K.
Cons: I personally think the breathability needs improvement. The tongue and heel padding could be made thinner to reduce weight to under 250 grams, which would be perfect!
Recommendation
The Codoon Second Generation R-21K has the workmanship of international brands and costs only 269 yuan. It is suitable for general runners for training and competition. However, for those who pursue speed, it is not lightweight enough.