My interest in New Balance first started when I saw my brother's modified MT101s. He improved the flexibility and made them zero-drop by removing a portion of midsole and slicing grooves in the outsole. After his positive experience with the shoes, I considered buying a pair for myself to modify, but then New Balance announced the Minimus line and I decided to wait.
The Minimus line of shoes appeared to be exactly what I was after: light, flexible, flat and wide. While I didn't buy the first Minimus Road shoe, the MR10, I watched the line closely and eventually purchased both the MR00 (road) and MT00 (trail).
It is from this line of shoes that New Balance released the Minimus HI-REZ; the most innovative shoe to bare the Minimus name.
- Heel-to-toe Drop: 0mm
- Weight: 3.7 oz, Men’s 9
- Upper: FantomFit – Meshy upper formed from what appears to be two material layers, one soft for against skin, one for a bit of structural integrity.
- Outsole: 42 independent rubber pods, extreme flexibility, solid ground feel, and enough protection for most road surfaces.
As I pulled the HI-REZ out of the shipping bag, I was instantly excited about how light, flexible and fun the shoes looked. A key feature of the HI-REZ is it's unique outsole. Instead of having a continuous rubber/foam/plastic outsole like most running shoes, the HI-REZ outsole consists of fabric base with individual rubberized pods that move independently allowing the entire shoe to flex incredibly well. The HI-REZ folds more like a thick sock than a shoe.
I put the shoes on as soon as they arrived and they felt fast. The light weight made my feet feel nimble and excited to run. While walking around the office the individual pods could be sensed underfoot but were not annoying.
For my first run in the HI-REZ I set out on a MAF 6 mile test (1 mile warmup, 5 mile test). As I started out, I noticed that my footplants felt solid and the sensation of landing on dense rubber versus foam was apparent. I also noticed that the landing didn't feel or sound "slappy". With other minimalist shoes I have noticed that if the outsole is too hard and not sufficiently flexible it sounds and feels like my feet are slapping as they land. I believe the extremely flexible sole allows the HI-REZ to flex with my foot during landing; preventing the slapping sensation.
As is typical when testing a new pair of shoes, I set out looking for interesting surfaces to run on. On asphalt and concrete the shoes performed very well, my landings felt solid but supported and were not at all painful. When I ran across dirt and grass the shoes were a joy. The slight give of the ground seemed to perfectly compliment the shoes' structure. The only surface that wasn't fun to run on was a gravely surface with pointy, medium-sized rocks. As expected - and noted by New Balance on their site - having a soft outsole means that objects can be readily felt through the sole and some of those objects can hurt.
The HI-REZ shoes offer good enough, though not the most, ground feel. While the independent movement of the pods allow differences in height to be easily sensed, they are thicker than other minimalist shoe soles and mute a bit of the ground feel. I personally prefer this balance of protection and feel because sometimes an extremely thin sole feels like a distracting exercise in rock avoidance. With the HI-REZ I get the fun of feeling different running surfaces, without the worry.
The HI-REZ toe box is soft and super flexible though not roomy enough for a thick sock (unless sized up). I believe the shoe is best worn either barefoot or with a thin sock. Since the upper has very little in the form of overlays it fits more like a slipper or a sock. The upper provides little resistance to flexing or folding with the foot. If the upper was more rigid the toe box might be more snug than desired, but since it flexes so well I believe the fit is acceptable.
One of the negatives I have noticed with the shoe is with the sizing - and it might only be a personal problem. I typically wear a size 10.5. With the HI-REZ the size 10.5 felt a little loose, especially without a sock. Specifically, the opening around my ankle was a little looser than desired and allowed debris to occasionally end up inside the shoes. (I think having fairly skinny ankles is part of my problem.)
In an effort to run more sockless miles in the shoes, I requested a size 10 from New Balance. When testing the size 10, the shoe fit better around my ankles but was a tiny bit tighter over the top of my foot than I prefer. Also, when I took the size 10 shoes out for a sockless run I ended up with an irritation on the top of my foot from a corner of material that sits over my big toe. I am not sure whether the irritation was due to my overly soft feet or the design of the shoes. I've since settled on running in a thin wool sock in my size 10 or slightly thicker sock in my size 10.5 if I am heading somewhere where a lot of small debris is likely.
Over the past three months I have run over 150 miles in the HI-REZ. The overwhelming impression I get from the HI-REZ is how fun it feels to run in them. The shoes are comfortable, super light, and perform so well that I often find myself looking forward to my lunch runs when I know I will be wearing them. The HI-REZ has become a favorite shoe on runs between 5 - 8 miles (I could likely go longer in them, but I have another favorite shoe for longer distances). On days when I am planning a MAF, or controlled heart rate run, the HI-REZ are the shoes I want to run in. When I run in the HI-REZ I continue to find that I feel very connected to my run, and very in-tune with how my body is moving. In the HI-REZ each footstrike seems to provide more information to my brain than I get from many other shoes; I can feel my foot easing into a soft, nearly silent, landing.
Over the last couple of months of testing the shoe's performance feels very similar to when I first received them. Since the shoes were already very soft, nothing on them appears to have broken-in, except for maybe a little stretching of the upper on the tighter fitting size 10's. The black rubber on the outsole is wearing and on some pods it has begun to separate from the gray rubber. I am concerned that the soles will only survive a couple hundred more miles - only time will tell. The durability of the outsole is something to watch-out for, especially on a $120 shoe.
The New Balance HI-REZ is a marvelously designed shoe. New Balance set out to accomplish something new with the shoe and they wisely started at the base by designing a very unique outsole. As an engineer, I can only imagine the problems that the fabric/pod based outsole provided the design team at New Balance, but I can definitely appreciate the final product. The New Balance HI-REZ is a shoe that is light, flexible, flat, low, airy, and oh-so-fun to run in.
I will caution runners to be honest about their level of previous minimalist shoe experience; this is not a shoe you can put on and expect to run miles in without first allowing your feet and legs to develop. If however, you are a veteran minimalist runner then you are likely ready for a fun ride. I'm looking forward to future runs in the shoes as I believe they are helping to improve my form and strengthen my feet. I am also excited to see if New Balance applies some of the technology developed for the HI-REZ into more of their products.