bimai 42k running shoes from 21k to 42k upgrade
This year, I was fortunate to receive a set of black Bmai running gear (T-shirt, shorts, compression calf sleeves) for review at the Chongqing Marathon. Wearing the purple Bmai 21K from last year's Codoon review, I unexpectedly achieved a personal best at the Chongqing Marathon. Therefore, when Codoon launched the 42K review, I immediately applied and wrote, 'Applying for the black 42K to complete the full set of black Bmai gear for the race.' Thanks to Codoon, my wish came true!
21K + full set of Bmai gear for Chongqing VS 42K + full set of Bmai gear for Lanzhou
This review mainly compares the 42K with the 21K.
Appearance
(1) Unboxing
Unlike the traditional paper shoe box of the 21K, the 42K uses a brand-new inflatable plastic shoe box, providing ample protection for the shoes while impressing with its design.
21K VS 42K
In addition to the shoe box, the inside of the shoes also uses inflatable plastic bags for protection and support, unlike the previous random stuffing of paper. This can be used long-term and helps maintain the shape of the shoes.
(2) Color
The 21K's main colors are purple (unisex), sky blue (men), and pink (women), which are very bright. The 42K's colors are not gender-specific, mainly black, purple, yellow, and white, offering a wider range of choices. Since I chose black for the Bmai T-shirt, shorts, and calf sleeves in the previous review, I chose the black 42K this time to complete the full set of black Bmai gear.
21K
4 color options for the 42K
Unlike the bright pink laces and tongue of the 21K, the 42K maintains a low-key black color consistent with the shoe body. The logo on the tongue naturally changes to 42.195K, and reflective materials are added to the logo and laces to enhance safety during night runs.
21K VS 42K
(3) Material
The upper and body of the shoe are similar to the 21K, mainly using mesh breathable material to ensure breathability, which is very important for marathon running shoes. The difference is that the 21K lacks shaping material in the forefoot area, resulting in insufficient wrapping when worn. The 42K improves this by adding two shaping materials in the forefoot, enhancing the overall wrapping and stability of the shoe.
21K VS 42K
The toe cap has hard material to protect the toes, and both the toe cap and the shoe collar have reflective materials to increase safety during night runs.
21K VS 42K
The 42K's reflective performance is excellent.
The arch area has Arch Support high-strength plastic material to enhance the support of the sole. Comparatively, the 42K's support material is lighter.
21K VS 42K
The 21K's heel rubber material is different from the forefoot, with the heel's black rubber being more wear-resistant. The 42K uses wear-resistant black rubber throughout, with deeper grooves to increase sole friction, significantly improving the 21K's previously reported insufficient slip resistance on wet surfaces.
On-foot Experience
Following customer service advice, I chose a half size larger for the 21K, size 44. The overall feel was good arch and heel wrapping, with ample space in the forefoot.
For the 42K, I chose my normal size, 43.5. Due to the addition of two hard shaping materials in the forefoot, the overall wrapping was good, and the forefoot wrapping was also strong.
21K VS 42K
Performance Testing
After receiving the shoes, I first ran a 10K on the track for break-in, then took them to Lanzhou for a full marathon. The main experiences are as follows:
(1) Breathability
Excellent. After a 10K run, there was little sweat, and the inside of the shoes was basically dry. During the Lanzhou Marathon, the weather was hot, and I sweated a lot and poured a lot of water on myself to cool down, with water running into the shoes along my legs. However, the shoes' good breathability ensured no stuffy feeling inside, and the moisture was quickly expelled.
(2) Comfort
Both the 42K and 21K felt very comfortable when worn, with no flaws in the parts that fit the foot. The heel and sole also had good adaptability. The first 10K road run had no discomfort, and the second full marathon run, although causing foot soreness due to the long distance, did not cause any discomfort from the shoes.
(3) Cushioning
As I am slightly overweight, I pay more attention to cushioning performance when choosing running shoes. The 21K's cushioning performance already satisfied me, with noticeable rebound and no discomfort in the knees after running. The 42K performed even better, with a full marathon run showing significant rebound effect and no knee discomfort.
(4) Slip Resistance
Under normal weather conditions, the 21K's slip resistance on asphalt roads was good, with strong grip and no issues on turns or slopes. However, due to the shallow grooves, many runners reported average slip resistance on wet surfaces. The 42K's sole rubber material and groove depth were greatly improved, and it passed several wet areas during the Lanzhou Marathon without any slip issues.
(5) Durability
Generally, the durability of running shoes depends not only on the material but also on the runner's gait, road surface, and environment. My running shoes always wear out the outer heel the most, and both the 21K and 42K were no exception.
After the first 10K road run, there was some wear on the outer heel and toe, but the wear on other parts was not significant, exceeding my expectations for durability. Comparatively, the 42K's durability was better than the 21K, with almost no wear on the rubber grooves.
After the second full marathon test, the 42K's rubber grooves showed some wear, related to the asphalt road conditions. However, the wear was not severe, and the original rubber grooves were still visible.
After long-distance testing, apart from significant wear on the sole, neither the 21K nor the 42K showed signs of delamination or thread breakage, indicating the excellent durability of the Bmai series.
Wear condition of the 21K after 10K test (heel) VS wear condition of the 42K after 10K test (heel)
Wear condition of the 21K after 10K test (forefoot) VS wear condition of the 42K after 10K test (forefoot)
Wear condition of the 42K after full marathon test (forefoot and heel)
Summary
As a cushioning running shoe positioned for full marathon races, the Bmai 42K's performance in all aspects has left me very satisfied. The wearing experience is not inferior to major brands like Asics and Adidas. The two reviews of the 21K and 42K have given me a deeper understanding of the Bmai brand and products. In the future, Bmai will be my first choice for marathon running shoes.
Thanks again to Codoon for providing the review opportunity and to Bmai for their excellent products! Looking forward to Bmai launching racing shoes soon!
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