Epic REACT Mods and Carbon Fiber experiments

[Four by Six]

In Nike’s Phantom press release today they are claiming they strategically placed elastic threads in the Flyknit upper, suggesting it is different than just an Epic upper without laces. I’m a bit skeptical it is different as I can feel elastic threads in the both Epic and Rise uppers. Once I get my hands on a Phantom, I’ll compare the uppers.

 

[Four by Six]

I intended to wear my grey pair of Rise for hiking, but somehow had my Triple Blacks with me on my last trip. After >20K steps per day, thousands of vertical feet ascended and descended, over sidewalks, cobblestones, crushed rock, sand, and even a raging river - I can honestly say the Rise is the best lightweight hiking shoe you will ever find. Here is a pic of the aftermath with absolutely no cleaning whatsoever - other than being a bit dusty, they held up well:

A similar trip I took 2 years ago in Pegasus Triple Blacks destroyed the shoes by the end, and I had to throw them away.

The only shortcomings I found were two:

1) Obviously, traction was an issue as I expected. However, not where I expected. Fine round pebbles on a harder surface caused me to slide, sometimes scarily close to a drop-off into the abyss. And whenever there was a thin layer of water on pavement, they would hydroplane like on ice, potentially twisting an ankle or knee in the process. Otherwise, traction was acceptable on most surfaces.

2) When descending high steep hills, there is nothing to keep the foot from sliding forward and crushing the toes into the nose of shoe. There are no laces, no flywires, and no midfoot lockdown to stop the foot from slipping inside the flyknit. The only thing that stops the foot sliding forward is the toes mushing together. Eventually, the toe nail on the pinky toe on both feet cracked and bled and needed taped up. However, I have plenty of hiking boots that have the same problem. My Pegasus with flywires did not have this issue though.

After hiking through knee deep water with them, I simply removed the insoles and hung them to dry out. The leather takes a bit longer to dry, but overall the shoe dried well overnight. In fact, I used the Rise without insoles barefoot as a water shoe at the beach for a few days. When I was done, I rinsed them in clean water and hung them to dry again.

 

[Four by Six]

In honor of the upcoming release of the Nike Epic Phantom Flyknit, I thought I would give an update on my original prototypes.

I've now logged well over 300 running miles in them, and countless additional walking miles. I'd have even more running miles, but I bought additional Epic shoes for my rotation and some Turbos for recovery days.

Here they are after only a water wipe down to remove mud from this morning's run:

Reviewers continue to make a big deal out of "how long will the REACT last?", even though many shoe reviewers crossed 300 miles with little to no wear on the exposed foam.

Here are my soles, both outsole and exposed midsole foam:

The only wear on the exposed foam is a small amount of "burr" like a rubber eraser makes. The area exposed from this burr feels just like all the other foam, so I don't think there is any loss of properties due to it. Considering the mileage, this is a trivial amount of wear.

Here is a pic of the "strikepad" where the sole takes the most load and wear and tear. You can see Nike was smart to make it more solid than the rest of exposed midsole.

The only part of the shoe that shows any wear is the insoles. They have completely flattened with no give whatsoever any more. The red Nike swoosh has begun to peel off both insoles.

I attribute the extreme wear on the insoles to the fact I had put carbon plates between the insole and midsole (I'll get to that next).

 

[Four by Six]

For those of you following this thread for the carbon plate experiments, I did indeed buy more carbon fiber supplies and continue to experiment with layups, resins, and infusing methods.

Here is a pic of my first carbon fiber plate that came out actually usable:

I have alternated with and without these plates over the 300 running miles of my uncaged Epics. So, that means these plates easily have over 100 running miles in them. And they show no signs of wear or losing springiness.

I have experimented with lots of different designs and have found there is a tradeoff between comfort and speed. I am able to make very stiff plates that yield well over 5% improved times, but they are too hard on the joints, tendons and muscles to be viable. I am also able to make a very flexible pair that yield no improvement whatsoever, but they somehow make the Epics disappear on your feet and you feel like you are floating over the pavement. The plates shown are my compromise plates. My fitness tracker data shows about a 2-3% improvement in times, and all my PRs were set with the plates in these shoes. I also use a pair of "floaty" plates in my daily wear Epics just because they are so comfortable. I liked them so much I made a pair of "floaty" plates for one of my pairs of Rise.

 

[Four by Six]

I've added a poll to the top of this thread... I want to fine tune my designs, but I'm not sure what people prefer. As I mentioned, there is a tradeoff between comfort and speed. At one end of the spectrum is super stiff plates that can shave over 5% of time off a race but are hard on joints/tendons/muscles. At the other end is super flexible plates that work with the react foam to feel like you are floating on clouds, even after a long day on your feet. And then there are compromise plates in the middle that feel really good and still shave about 2-3% off times. Please vote accordingly.

I currently only have a single size 10 mold for Epics, as that is the size of my feet. I have plenty of leftover test plates size 10 of various designs. I haven't made any other sizes yet as the molds are very expensive.

 

[Four by Six]

All my size 10 leftover samples are spoken for. For those of you who asked about price, they are free as I'm only looking for feedback at this point. For those who asked about fit, they will fit the ER1, ER2, Rise, and upcoming EP. I might do another run of them, but I will probably wait for early feedback before using up my remaining supplies of CF.

Since no-one answered the poll yet I'm probably going to just make all future plates my "best compromise" version. Now I'm wondering if I should get a couple more molds of different sizes, maybe US size 9 and 11? I tried to edit the poll to be a question on size, but it won't let me, so I just added the sizes as additional poll choices and enabled multiple choice.

 

[Four by Six]

I have been experimenting with CF plates for my Turbos, but I'm still playing around with layups and flex points. Since the internal shape and strobel board of the Turbos are so different than the ER, they would require a different mold.

 

[Four by Six]

I have been experimenting with CF plates for my Turbos

I realize this is an ER thread, but I've received some questions on why a plate in the Turbos.

I think the Turbos should be called "slow-downs". I love my Turbos and think they make a great recovery run shoe, as they are so cushioned. They also have amazing energy return. The problem is this energy return is directed vertically up/down, not horizontally in the forward direction. If you watch videos of people running in the Turbos, their head or legs are bobbing up and down. The shoe has great bounce and pop, but the shape of the shoe does not translate that energy return to forward motion.

The Epics and any of Nike's shoes with same midsole shape do not have this issue. While the React has much less energy return than the ZoomX, the shape of the midsole/strobel board in the Epic naturally throw that energy forward.

I find it ironic that a shoe called "Turbo" is my slowest shoe. According to my fitness tracker data, I am consistently 2-4% slower in Turbos than any other shoe in my rotation. However, the shoe has amazing "pop", so I am just trying to redirect that "pop" downward into forward motion, while still maintaining the cushioned comfort I love.

 

[Four by Six]

The shoe has great bounce and pop, but the shape of the shoe does not translate that energy return to forward motion.

If you look at this image I previously posted elsewhere, you can see the toe-off of the Turbo. When the foam is compressed, it then rebounds, and with the Turbo most of the energy is back up again. (Note: Not my original picture, only my edits to my screen grabs from another members video)

If you compare to the Vaporfly's toe-off, the foam is compressed, and by the time it rebounds, most of the energy vector is pointed forward (though still a bit upward).

Both shoes rebound up and forward, but the plate in the Vaporfly helps re-direct more of the energy forward during toe-off. The Vaporfly achieves this with the "ice cream scoop" shaped rigid plate. The Epics' shape naturally does this without any plate needed, though my plates help the foot store more energy during the compression phase.

If Nike put a thin layer or inner core of ZoomX in the Epics' React midsole, that would be unbeatable.

 

[Four by Six]

My first Phantoms arrived. Comparing the flyknit upper to Epics, I can see no difference between them in stretch. So, Nike's claim to put more elastic threads is just Marketing.

They fit tts for me. While other reviewers claimed a looser fit than Epics, for me they fit as tight in forefoot as ER1s.

The inner heel reinforcement in the Phantoms is a hard synthetic rubber of some kind. I'm not taking these apart, as I paid full retail for them. I noticed the surface is rubberized and grabby. It seemed to grab my sock and skin where it meets the flyknit. I won't know if this is a problem until I run lots of miles in them.

The inner reinforcement in the ER1 was a thin sheet of open cell foam that was folded over 3 times and then compressed very thin, covered by a piece of synthetic suede. I know because I fully took apart a pair of ER1s. Great support but also soft.

 

[Four by Six]

Ran in the Turbos without any CF plates this morning, as I wanted the cushioned comfort, the same 10K loop as always. When I looked at my run data afterwards, I was shocked. For the same average heart rate, my time was a whopping 12% slower than the PR I set yesterday in my ER1s with my fastest CF plates. Of course, my fastest plates are brutal on my muscles, tendons, and joints. Which is why I needed the soft Turbos for today's run.

I think I know why the Turbos are so slow (at least for me). The ZoomX almost seems to fight my stride, almost like it is pushing back a little. The flex point of the shoe seems too far rearward toward the heel. And there needs to be more offset to force the foot to roll forward and off the toes. I have to force myself to be on my forefoot, leaning forward, and physically fight the midsole to get to a good toe-off.

I'm not complaining, as a recovery trainer should be slower and more comfortable. However, despite the Turbo name, this shoe is slow for my stride and foot strike type. YMMV.

 

[Four by Six]

Ran my 5K loop this morning with my fastest plates in ER1s. My time was 12.5% slower than my PR set in same shoes. You have to work your muscles harder with these plates for them to make you faster. My muscles were just too fatigued from the last two days to get up on my toes and flex the plates to load the React foam up.

 

[Four by Six]

The inner heel reinforcement in the Phantoms is a hard synthetic rubber of some kind. I noticed the surface is rubberized and grabby. It seemed to grab my sock and skin where it meets the flyknit. I won't know if this is a problem until I run lots of miles in them.

I sent my first Phantoms back to Nike and received my refund already. The rubbery inner heel cup rubbed the top of my achilles where it meets the flyknit and caused a blister, as reported by other NT members, even with thick running socks. I think Nike made it rubbery to help hold the heel in place. This is a shame.

I've ordered several pairs of the Nike by You versions of Phantoms, since based on the web tool and pics here on NT, I think they might actually be laceless Epic React 2's instead of Phantoms and not have the problem. I received a shipping notice from Nike that the first pair will arrive this week, so I should know soon if they have the suede or rubbery inner heel reinforcement.

I'm taking a bit of a gamble/risk here, but I wanted to cop the custom Phantoms before they are gone.

 

[Four by Six]

I think they might actually be laceless Epic React 2's instead of Phantoms and not have the problem.

I received my first pair of NbY (IDs). I can confirm that they are indeed laceless Epic React 2's, and not Phantoms. That is a good thing.

Here's a pic. The triple black upper option is a much more lighter grey than it appeared online. It almost has a blue tint to it. But it then fades to a very dark solid black. I think it looks great.

Why do I say they are "laceless ER2's" instead of phantoms?

They do not have the plastic piece to prevent mid foot spillover (which isn't needed and rubs the foot). See above pic.

The upper flyknit pattern has the voids for lace holes, showing this is a ER2 upper without holes punched in them, rather than the phantom upper which does not. This is a good thing, as the ER2 upper feels better in the top forefoot:

The rear outer heel cup is much lower in the back. The phantom goes much higher, the ER2 is much lower. This is a good thing, as the higher hard cup is not needed.

And finally, most important, it has a softer less grabby inner heel reinforcement. I noticed is is black, instead of white, but it is softer and not grabby:

I am very happy with these laceless ER2s. I own a huge assortment of running shoes, and I think these are simply the best running shoes you can buy at any cost. Especially when I add my carbon fiber plate to the insoles. And for casual wear they are super comfortable, and quick to slip on and off.

 

[Four by Six]

My blue IDs came in...

 

[Four by Six]

No turning back now. I just permanently glued my floaty plates in my blue IDs and my compromise plates in my black IDs. I’m thinking about getting a pair of red IDs to permanently glue my fastest plates into. I found in previous experiments that they work better glued down as they are held in contact with the react foam. Without gluing them down the plate can separate from the foam during extreme toe off. They still work, just not as well.

 

[Four by Six]

I'm still getting questions on the difference between a Phantom and what I am calling a laceless ER2. Here is an annotated pic, with the laceless ER2 in black on left, and the Phantom in white on the right. Hope this helps...

 

[Four by Six]

If the buzzword / marketing gimmick of 2018 was "energy return" foams, then I guess the buzzword / marketing gimmick of 2019 will be carbon fiber plates. It seems like all the manufacturers will be releasing a shoe with carbon fiber plate before years end, and consumers are paying top dollar for them and they are selling out day of launch. So much hype.

Well, having looked at what is available thus far, only Nike really is using the Carbon Fiber correctly. The others are just adding a CF plate to the shoe and hyping it. But only Nike is putting the right plate, of the right kind, in the right location, with the right foam to really work correctly. One manufacturer is putting a flat plate with EVA foam. Another is putting a rigid curved plate. Another is putting a curved flexible plate. None have actually modeled what is happening. Except for Nike. After a year of experimenting with my own carbon fiber plates, I think I finally understand the foot dynamics, and what the CF plate does and does not do. My laceless ER2s with my hand layup custom carbon fiber plates are the best running shoes I've ever used - on par with my flyknit Vaporflys, just more stable and versatile. But don't waste your money on the other guys/manufacturers. I am confident they will eventually figure it out, but they haven't yet.

I'm not being a Nike fanboi here, I'm just stating what I've discovered in my experiments. Nike really got it right with their Vaporflys. Everyone else is just guessing for now.

 

[Four by Six]

OK, it's been too long... time for more crazy shoe mods!

First some background info. Some long term Epic React shoe reviewers have noted a "hot spot" in the middle bottom of the foot where the creases meet. I also notice what feels like the foam "bunching up" there, limiting foot motion a bit.

And if you look at the wear pattern after several hundred miles, it does appear to be most worn in that spot:

Furthermore, if you look really close you can tell Nike already made the grooves in the REACT foam deepest there. They must already realize the foam has to flex more there than elsewhere.

So where is this spot on the foot? I circled it in red here:

Apparently, Nike already realizes this is an important location in the shoe, as there is a small hole in the strobel board at this exact location, as shown here:

The location of this hole matches perfectly with the following location on the bottom of mid/outsole:

You can see how the outsole and midsole are perfectly shaped to the anatomy of the foot. Nike really put some thought, research, and engineering into the Epic shape, which is why I am such a big fan.

OK, enough background info. Time for the crazy mod...

When running with my Epics, I can feel the foam bunch up in this location. Not too bad, but noticeable. When I add my carbon fiber plates, I can feel it much more pronounced. It dawned on me I could help the situation by removing some foam here. Engineers call this a "relief cut" as it gives a place for excess material to go when something is bent.

Ideally, the relief cut would be a diamond like this:

However, I wasn't confident in my ability to cut a nice diamond shape through such thick resilient foam. So I though about it a bit and decided a circle would be a nice approximation, and might actually make a better relief shape. So I used a coring hole saw to make the following relief cut:

Notice, I did not try this on my new IDs. I used my oldest pair of triple black ER1s that already have over 200 running miles on them. Here is what the cores looked like when I was done:

Here's a pic of the crazy hole from the inside of the shoe:

So, you might be thinking, "what if you step on something sharp?", but remember I wear a carbon fiber plate over the hole.

It was already late when I finished, but I couldn't resist trying the shoes out on a quick run around the block. So how does it feel? Terrific. The tight area where the foam bunched up is gone. The ball and pads of the foot feel more free to move and flex during all the stages of foot strike and toe off. It feels like you are wearing a Nike Free shoe now almost.

My initial impression is I could have made the hole much smaller and achieved the same effect. I chose the size based on the wear pattern on the shoe, but it feels like maybe it is a bit too big. I will try them again on tomorrow's full run.

 

[Four by Six]

I did my morning run in my Epics with the relief cut.

I first did my warmup without the carbon fiber plates. I put a piece of Kevlar braid over the hole to protect the bottom of my feet in case I accidentally stepped on something sharp. My impression was the same as last night - I think the hole might be a little bit too big.

Then I put in my fastest CF plates, as that is the only pair I have left that is not glued into shoes. During and after the run I came to the conclusion the hole is perfectly sized for use with the CF plates. It did not feel too big, like without the plates, nor would I want it to be any bigger. Just right.

How did it feel? Amazing. Throughout the entire stride from foot strike to toe off, and all run paces, it felt better with the hole than without. I have over 200 running miles in these shoes without the hole. This felt better.

 

[smithma388]

Thanks for all of the updates and experiments. Very informative as well.

 

[wayniac211]

Repped for consistency

 

[Four by Six]

Thanks, guys... Unfortunately, I've run out of donor shoes to do experiments with. I tried two Nike outlets last weekend with no luck. I'm gonna take a road trip this weekend and try to find some cheap ER2s on sale. If I'm going to be destroying shoes with my experiments, I don't like to pay over $75 for them. I'm not going to risk my $200 iDs.

After over 30 running miles in the crazy hole ER1s with carbon fiber plates, I still think they feel great, but I want to try a smaller hole.

Also, I've run out of my CF plates (guess I gave too many away), so now I need to make more. I'm out of CF supplies, but there is a new type of CF from a supplier in Japan I want to try out. It should be even better, and I'm already using the same stuff SpaceX, NASA, and Formula One uses. I'm trying to find a plate design that gives me the speed of my fast plate (currently in crazy hole shoes) with the comfort of my compromise plates (currently glued into my black iDs).

 

[Four by Six]

I sent my first Phantoms back to Nike and received my refund already. The rubbery inner heel cup rubbed the top of my achilles where it meets the flyknit and caused a blister, as reported by other NT members, even with thick running socks. I think Nike made it rubbery to help hold the heel in place. This is a shame.

I just looked at a pair of Phantoms in a Nike store that were a later CW, and the inner heel cup appeared to be the soft white suede I like, so maybe they corrected the heel rub issue with the original CWs.

 

[Four by Six]

Ran 7 miles this morning in crazy hole shoes on mostly crushed gravel to see if any rocks would build up or get stuck in the hole. Nope, hole was very clean at end. I still like the feel of the hole better than no hole.