Epic REACT Mods and Carbon Fiber experiments

[Four by Six]

Eddbud has been discussing lately the pros and cons of high stack, soft foam shoes. The pros are legs feel fresh after long runs, and cons they create unnatural muscle movements like wearing platform shoes.

Here is a screengrab from Kofuzi's latest video, where i captured a dangerous shin/calf motion during landing to toe-off with Nike's latest Invincible ZoomX shoe. This might have been caused by the strong winds he was counteracting. You can actually see the muscles shifting and trying to keep him stable, though admittedly the fisheye distortion of the lens and water drops do exaggerate the effect.

 

[Four by Six]

I've been excitedly awaiting the availability of the Saucony Freedom 4, as it switches from beaded TPU to beaded Pebax midsole. I am hoping this will be a great compromise shoe - the energy return and pop of a Pebax midsole with the stability that a lower stack height and offset gives.

A brand promo video came out recently that concerns me the midsole might be too hard. Here is a screen grab of a runner jumping off stairs and landing flat. That is not much compression for a hard landing.

Here is the same runner in a fast run. This looks a little bit better, with good landing and toe-off, but still I would want a bit more foam compression.

The Saucony foam designer recently said in an interview that they have started to pack the beads tighter together to help maintain the pop for more miles and help stability. However, this makes the midsole stiffer on day one.

The Saucony marketing guy in charge of the Freedom4 was pitching it for weight lifting, HIIT, and CrossFit, so it looks like they are trying to transition it from being a minimalist runner to a general purpose workout shoe.

A shoe reviewer that evaluated an early sample noted that the heel bevel is gone. The heel bevel prevents the back corner of the shoe from scraping the ground later in a run when the legs are tired and/or when going down steep hills. However, the heel bevel causes instability during workouts, especially when doing weights. This would also suggest Saucony is trying to transition the Freedom4 from a running to an all purpose workout shoe.

 

[Four by Six]

I am also awaiting the New Balance Rebel v2. It is an entirely new shoe, so I'm not sure why NB is calling it Rebel v2. It is a plateless shoe with Pebax and a lower stack height of midsole foam. It could be a great compromise shoe as well. However, due to covid related delays, it missed its launch date.

Here is a screen grab from Believe in the Run's review of a preproduction prototype. Looks pretty good. A bit sloppy in the upper, and a bit wild in the heel, but not bad.

 

[Four by Six]

I hate to sound like a broken record, but nothing comes close to the Nike VF. Plated shoes have proliferated like crazy, and there are plenty of options out there, but still today nothing comes close to the VF. While I deeply respect the intellect and hard work of the other shoe companies, they simply do not understand the elements that make the VF work so well.

Here is screen capture from SJD's latest VF2 update. OMG, that shoe is perfect. Note the heel making early contact, even with a forefoot strike; the gentle roll towards forefoot. The nearly maximum compression of the ZoomX; the release of the compressed foam at the right time of toe off; the ice cream scoop shape directing the pop off in the horizontal vector; the huge hang-time after toe off. If you ever use a shoe pod when running with the VF, you will be amazed at the long ground contact time, and the even longer hang time per stride. Both the shoe and Seth's stride is amazing!

 

[Four by Six]

New Balance Rebel v2. It is a plateless shoe with Pebax and a lower stack height of midsole foam.

I misspoke when I said the Rebel v2 is Pebax. One review says nitrogen infused TPU, so basically Boost with less weight. Another review says autoclaved TPU/EVA blend. NB doesn't directly say. They just say their FuelCell foam can be anything and varies from shoe to shoe.

Interestingly, I found one article where a NB shoe designer said they are able to use different densities of the same foam to increase stability without a plate, but didn't clarify which shoes have the feature. He said in one shoe (not specified) he used denser FuelCell around the edges and bottom as a container to hold a lighter bouncier FuelCell pad in the middle where the foot strikes.

Though the Rebel v2 missed its launch date, it is now due out mid April.

 

[Four by Six]

While my Turbos are my slowest shoe by about 4%, they are still my favorite daily trainers. I don't know exactly how many miles I have on them, as my Nike Run app burped during an iPhone update. But it is at least 500km.

The outsole is holding up great. There is only a little bit of wear in the middle of the forefoot and where I toe-off.

There is a lot of wear in the outside rear of the heel, but this is not from heel strike or foot landing. On my longer runs, the muscles that lift my legs get tired and I start to drag the heel a bit when I am returning my leg to the front position.

 

[Four by Six]

I'm starting to wonder if the upcoming NB FC Rebel v2 will live up to the hype. The extra wing or flair they put on the lateral side of the forefoot, and lack of support on the medial side of shoe seems to create a wicked ankle motion, as seen in this screengrab:

 

[Four by Six]

My NB Rebel v2's came in... I got the two tone red/black CW. My plan was to try and remove the contrasting baby blue NB logo, if possible.

Here is before any modifications:

I tried my usual solvents, hoping I could peel the sticker away, but it appears the logo is melted into the weave of the upper mesh.

The blue is a very weak paint, like nail polish. It came off very easy. The black "shadow" of the font is much tougher. Here is with only the blue removed:

The black took much more solvents and rubbing, but eventually came off in little balls of black. Here is with the black removed.

Of the three options, I prefer the black shadow lines the best. The weird blue clashes with rest of upper (though the bottom outsole has some rubber the same color). The clear glue only looks a bit odd, and I bet it picks up dirt, so eventually I will have a dirt NB logo. The black matches, and is a bit more subtle.

Just walking around the house, the shoe leans toward the medial side, and it also collapses toward the medial side when any weight is put on it. The shoe feels like an "anti-stability" shoe. I think maybe NB should have made the shoe perpendicular to ground with no cant, and maybe built up the medial side a bit more or used slightly firmer foam there.

Next I'm going for a 10K run to try them out.

 

[Four by Six]

Back from my 10K run. Set a new PR for both 5K and 10K, and not by a little either, by 3%. However, this does not necessarily mean the RebelV2 is fast. My heart rate was substantially higher than normal, so it just means I worked harder. I typically limit my HR to threshold or lower, but I felt like seeing what the new shoes could do, and the weather was great for a change. I will need lots more run data to draw any conclusions on run efficiency.

The shoes are definitely bouncy. They do not give the long hang time in the air like CF plated supershoes. So I tried to increase my cadence. They also do not give the pop like CF shoes, it is more of a bounce. At least you can feel the energy you put in coming back out. With my Turbos, they soak up all the foot impact and then you never feel it coming back - it just dissipates.

I'll give some comments on the shoe design in next posting below...

 

[Four by Six]

The RebelV2's are a lightweight, bouncy, fun shoe for daily training. They do have two design shortcomings though.

First, the medial side simply collapses under weight. If you look at the midsole design, it appears there is additional foam and a medial "posting" included. However, I think it is just for show and there isn't a real support feature. Or maybe it is a real feature and it would be much worse without it.

Second, the "wing" or "flare" they add to the lateral forefoot is a terrible feature. They greatly reduced its size from V1 to V2, due to lots of criticism.

RebelV1 wing:

RebelV2 wing:

My first km in the shoes was terrible due to the wing. I eventually figured out I needed to move my footstrike rearward, from mid foot strike to mid/rear strike. I needed to land on the start of the wing to pre-load it. Then I got a nice foot transition and a lot of pop out of the midsole. However, this was difficult to do and very tiring. My ankles did hurt after the fast run.

I am already considering modifying the shoes by simply cutting off this wing and seeing what impact that will have on foot transition.

 

[Four by Six]

I went ahead and cut the wing off my Rebels. After playing with various power tools in my workshop, I decided the best approach would be to just use a scalpel. These new superfoams are tough to work with. The midsole actually has a curved line molded in that shows where the curve would be without the added wing, so I just followed that line.

Here is the new curve from the bottom outsole view of shoe:

Here is the end result on both shoes from top view:

I've very happy with the end results. I hope this mod works!

 

[Four by Six]

After trimming the wings off, I thought it would be a good time to dye the midsole black. I've always been a fan of black midsoles, especially with the Epic Reacts, and I think this colorway screams black midsole needed. Here are some pics after the first of several coats of black:

 

[Four by Six]

I went ahead and cut the wing off my Rebels... I've very happy with the end results. I hope this mod works!

I ran 10K this morning with my Rebelv2s, and I'm very happy with the shoe mod. The heel to toe transition is now very nice. I had no trouble maintaining good foot form during the run from beginning to end.

 

[Four by Six]

EDDBUD recently wondered what the NB Rebelv2 would feel like with a plate, either nylon or carbon fiber. He assumed it would feel just like the TC or RC.

So I figured, why not try it out and see!

I pulled my carbon fiber plates from one of my pairs of Epic Reacts to see if they would fit the NB Rebelv2. While not a perfect fit, it was close enough to try out.

After a 10K run, it was very eye opening. The CF plate definitely stabilizes the foam. Gone were some of the knee pains the shoes give me. The plates do not give the pop or air time that the TC or RC give you, as the shape has to be different for that. The pop and air time effect needs the plate to begin on top of heel midsole and transition to the bottom of forefoot midsole, preferably with a complex curve. However, the shoe transition felt very natural whether at a slow, medium, or all out pace.

I didn't feel faster, so I assumed my times would be average. Much to my surprise, I set 6 new achievements in Strava, including 2nd fastest 10K:

The plates are definitely staying in the shoes, at least until I can make a custom pair for them. With the two mods of cutting off the "wing" and adding the plates, this is now my favorite training shoe. I'd still pick the VF4%FK for race day though.

 

[Four by Six]

I've never been a fan of the Phantom 2's, but the stores are getting low on stock and I doubt there will be a Phantom 3. I found a pair of black/whites on the wall at the Nike outlet. They were not reduced much, compared to other pairs on the wall, but I thought why not and got them.

My main gripe visually with the P2's is the front pull tab being extended all the way down the tongue area. I just think it looks awkward. I got these P2's with the goal of seeing if I could remove the bottom part of the front pull tab with a seam ripper tool.

Here is a pic before trying the mod:

There were no guarantees this would work. The elastic bands might terminate under the pull tab strip, or there might also be permanent glue in addition to the thread seam. It turns out the elastic bands do continue under the pull tab unbroken, there is a nice wider loop of flyknit there, and there was only weak double sided foam tape which was easy to remove. I think the tape was to hold the fabric strip in place while the seam was sewn on a machine.

Here is a pic after the mod:

I like the look much better now and they feel the same.

 

[Four by Six]

I still run every morning, usually a 10K, and my current running shoe rotation:

1. Nike Epic REACT Flyknit version 1, triple black. Mods: Stiff carbon fiber plate added under insole, removed inner rubber strap between forefoot and heel, hole drilled in forefoot midsole.

2. Endorphin Speed, 1st gen, but second manufacturing run. Mods: None! I could not think of any way of improving these. The beaded Pebax midsole is a bit stiff, and I read that they got complaints it was too soft so they stuffed the beads denser in second manufacturing run, though that might just be an internet rumor.

3. New Balance Rebel version 2. Mods: Cut underpronation wing off midsole/outsole, added flexible carbon fiber plate under insole, painted midsole black.

My race day shoes continue to be Nike VaporFly 4% Flyknit. While my modified shoes can at times be faster than the VF, nothing is as consistently fast as the VF. And I prefer the flyknit upper and lower stack height, compared to the newer Next% versions. My current Half Marathon PR is with this pair.

I've retired my Turbos to recovery runs and daily casual wear, as they are just too slow for anything else.

I'm considering retiring my OG Epics, as I've noticed the midsole foam getting stiffer with age. I think the synthetic rubber in REACT foam gradually hardens with age. I wish I did not glue the carbon fiber plates into the shoes, as I'd love to put them in new pair. I currently can't make any more CF plates as I'm out of supplies and my mold is wore out.

 

[Four by Six]

You probably guessed what was coming next... The elastic bands were a bit tight and I wondered what the Phantom2s would look like without the contrasting white stripes. If the elastic had been black, then perhaps I would have kept them.

Without the elastic bands, the shoe still feels okay, not sloppy at all. The P2s were never good enough for anything athletic anyway, so if they are going to be casual wear, they might was well be very comfortable too.

 

[smithma388]

Updates to my favorite thread. Glad you're brave enough to tinker with your shoes.

 

[Four by Six]

I prefer black midsoles, especially for work shoes. The white draws too much attention at first and then yellows and looks dingy. The black Phantom 2's scream they need a black midsole. Since the upper has white accents, I thought I would try to keep at least the white line between the upper and midsole.

Here are pics after 2 coats of black. I use Hes' technique of cleaner, black dye, black paint, clear coat.

I like the results enough that I think these just became my new work dress shoes. The camera just doesn't do the lofted flyknit justice. The lofted flyknit looks amazing in real life.

As for removing the elastic bands, they are much looser now, but I haven't had any problems with stability or the shoes wanting to come off. There is a bit of heel lift, but they had that before I removed the elastic as well.

 

[Four by Six]

I'm considering retiring my OG Epics, as I've noticed the midsole foam getting stiffer with age.... I wish I did not glue the carbon fiber plates into the shoes, as I'd love to put them in new pair.

In yesterday's run, during the kick at the end, the plate in left shoe came loose. I thought this would be a great time to try and extract them and put them in a new pair of shoes.

I was able to find plenty of ER1s and ER2s still at the outlets, and many priced near retail years after their discontinuation. I went with the closest thing I could find to triple black, the black/grey/black ER2s.

Here is what the new vs old shoes look like. I probably got over 1000 miles on my ER1s, so I got my money's worth.

Here is what the plate looked like after pulling it out. It had separated from the strobel but was still stuck to the insole. These plates have several hundred miles of running on them. There were a few micro cracks near the edges, but they still look in good shape and have plenty of pop left.

I put the old plates in the new shoes and this time used a less permanent adhesive, as I may want to move them to a newer shoe in the future.

 

[Four by Six]

I have a pair of VF Flyknits that I love and they are still my race day shoes. I've never bought a pair of Next 1's or 2's because I do not like the mesh upper and the way it feels plasticy and bunches up when my foot flexes. Yes the high tech mesh is lighter and does not gain weight in the rain or with sweat, but I never cared enough for it to pay the huge price for them.

When the Next2's hit the NbY, I noticed that they offered a Flyknit upper like my VF's have for a $10 upcharge. I zoomed in the picture all the way and it looked like they same material. So I took a chance and ordered a pair with as close to a triple black CW as the design tool would allow.

The shoes arrived today. I have not run in them yet, but they feel great on the feet. The Flyknit was very tight when I first put my feet in them, but it immediately stretched out properly. The shoes are about a half size longer than usual, but I can't go down a half size or they would be too tight and I'm worried the arch would then be in the wrong place on my foot.

 

[Four by Six]

After a week long business trip, I finally got a chance to run on a standard 9K loop I have data on in my new Next2%FKs.

Just the hard data: Last three runs in nonplated running shoes were 5:18, 5:14, and 5:40 min/km averages. The same run in Next2%FKs was 5:05 min/km average. That is about 6.5% faster. If I drop the 5:40 data point, as I had a poor run that day, the Next2%FKs were about 4.1% faster.

Subjective comments: I've noticed in videos of other runners the Next% has a funky long and offset toe that causes the upper to bunch up on toe-off and be a bit longer than previous VFs. I found the same to be true here. The toe is a half size longer than typical, even with proper fitting shoe. The plate ends in the right place, so this is just an oddity. It didn't hinder proper toe-off, but I did notice my left big toe nail was cracked at end of run.

I was hoping the shoe would be more stable than previous plated shoes, but it was just as unstable in the heel. My VFs, Rebelv2s, Speeds, and now the Next%s are all very unstable. Running on smooth level payment is okay, but running on steep downhills, sloped roads, or wooden planked boardwalks is very unsettling.

I will probably alternate between my Speed1s and these Next2%FKs on my upcoming runs to get comparison data. I'm not sure if the Next2%FKs will replace my VaporFly Flyknits as my race day shoes, as the VFs are much lower to the ground, lighter, and more stable and give the same 4% gain. I do have some helpful mods in mind for the Next's, but I'm not quite ready to cut into these expensive shoes yet.

 

[Four by Six]

Yesterday I ran a HM in my new VFNext%2 Flyknits. About a 2 hour run, so not fast, but about all I'm capable of these days. The shoes did great but were a bit scary on the wooden planks of pedestrian bridges. I noticed in the last few km, the plate in the left shoe started vibrating like a tuning fork at toe-off. The right one did not do this. Both of my VF4%FKs resonate at toe-off, so it wasn't a huge surprise. And my right big toe nail cracked, just as my left did previous run. I noticed that at toe-off all the force is on my big toe rather than spread out among all the toes like in my VF4% and Speeds.

 

[Four by Six]

Let the mods begin!

I don't care for the Elfish shoe point at the rear of Next%'s, and during steep downhill portion of runs, the point does catch on the ground a bit. So, I took a knife and cut a line from the seam between ZoomX layers, downward, just missing the Nike symbol imprinted on the heel outsole:

I also don't like how Nike uses the midsole paint scheme to accentuate the curve of the plate inside. The plate is at the seam between the two layers, there is no need for such silliness:

So I ordered the CW with the front midsole and transition line painted black, with plans to manually paint the rear part of top layer of the midsole to match. Now only the bottom half of the ZoomX midsole/outsole is white. Everything above the seam is black:

I think the end result looks much better:

 

[wayniac211]