Latest revision as of 09:57, 23 January 2018

The Nike Vaporfly 4% is a much-hyped shoe, which is based on the shoes Nike developed for their attempt to break the 2-hour marathon. It's an expensive shoe, retailing for $250, and even at that price it's hard to find. There are rumors that Nike are restricting supplies to drive up interest. The shoe is unusual in that it has a carbon fiber plate running through the midsole. Given all the hype, I was not expecting much from the Vaporfly 4%, but there are aspects to the shoe that have really impressed me. I'd say it's a mixture of the awesome and awful, though not in quite the ways I expected.

• The shoe has remarkable cushioning for its weight, with my measurements putting it close to the top of the table. I ran with a Hoka Clayton on one foot and the Vaporfly on the other and the Clayton felt hard and dead by comparison. The Vaporfly uses a new type of foam made of Pebax, a compound that has previously been used in harder materials like Mizuno's Wave Plate. It will be interesting to see this foam in other shoes, especially something closer to a "racing flat". There is a rumored Reebok Floatride Racer using Pebax foam, but no details, and I've reviewed the Reebok Floatride Run which uses Pebax.
• When you wear the shoe, it has an amazing amount of bounce. It's far more than you get in TPU shoes like the Altra Escalante, and feels like there's a spring under your foot. It seems like the carbon fiber plate is acting more as a spring for the rear of the shoe than for toe off. This bounce is immediately obvious, even walking around, and feels different to every other shoe I've tried. Even at the end of a marathon length run the bounce is noticeable and helped me keep up the pace. (Check out my review of the carbon fiber VKTRY Insoles for comparison.)
• I couldn't detect much difference in toe off from any other shoe, which was disappointing. The forefoot is quite stiff compared with other shoes, but given the forces involved at toe off, this doesn't seem to be enough to make much difference. Of course, a tiny difference in efficiency won't be noticeable immediately, but could make quite a difference to your finish time.
• When I ran it the Vaporfly using a pure forefoot landing (without any heel contact) I found the Vaporfly lost all the bounce and felt very dead. (If you're a pure forefoot runner, I'd look elsewhere.)
• The Vaporfly claims a 10mm drop, and my measurements showed 12mm, but this is reduced to 8mm when loaded. This is normally way more than I can tolerate, but I had few problems in the Vaporfly.
• The rear of the shoe feels quite unstable, rather like I'm on a balance foam mat rather than a shoe. It's like the shoe is only supporting me heel directly under the ball, which is rather disconcerting.
• The forefoot of the shoe is even worse, with the area under the ball of the foot lower and softer than the rest of the forefoot. This means that the shoe forces your foot to pronate more than it naturally would. I measured the area under the ball of the foot as 1-2mm lower than the rest of the forefoot under load. I suspect that the carbon fiber plate does not extend under the ball of the foot for some reason, though it's hard to prove. If I try bending the forefoot of the shoe with my hand the area under the ball of the foot doesn't seem to be as stiff.
• I found that I had a tendon pain in my ankle as my calf muscle subconsciously attempted to limit my foot rotation. I had to consciously relax and allow my foot to rotate in, which is rather disconcerting to say the least. Normally I only get this with worn out shoes. After an adaptation period of sore ankles, I found my legs adapted fine to the additional stress, though I've always been aware of the instability.
• Initially, the outsole had surprisingly little grip, feeling slick and unsure on anything that isn't a firm surface. After I'd put some miles on them, the grip seemed to improve and was remarkably good, except on gritty asphalt where the grit acts like marbles.
• I found the toe box was not as bad as I expected, though running 20 miles without cutting open the toe box resulted in a minor blister.

Overall, I feel like I'm faster in the Vaporfly than other shoes by a noticeable amount, which is quite astonishing. This is hard to confirm, but my Heart Rate and perceived exertion seem noticeably lower for a given pace and Stryd Power Estimate. On the other hand, I feel like the Vaporfly has a real risk of injury, adding stress on to ankles and knees. After many hours of consideration, and hundreds of miles of running, I've rated the Vaporfly as "best of the best" in spite of its many flaws. It's expensive, almost impossible to find, and risks injury, but it's just so good that I think if you can handle the extra stress, it's worth it. (I use The Science of Running Shoes as the basis of how I test running shoes and what you should look for in a running shoe.)

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  Nike Vaporfly 4% top

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  Nike Vaporfly 4% outside

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  Nike Vaporfly 4% bottom

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  Nike Vaporfly 4% inside

This review was made possible by readers like you buying products via my links. Sadly, I don't have a link to the Vaporfly as it's so hard to find. However, I don't only review products that I have affiliate links for, and I buy all my gear at the same retail outlets you do to avoid even subconscious bias. I'd like to thank the many readers who buy products through the links on the left-hand navigation bar. Your funding for this site helps enormously.

1 Characteristics

• Cushioning . The cushioning of the Vaporfly is impressive, but the numbers on my comparison chart below don't really convey the level of shock absorption and bounce. One way of conveying this is that the Vaporfly is to a Hoka what a Hoka is to a racing flat. This sense of bounce is immediately obvious when you first put the Vaporfly on. You can tell the difference just standing in them, and the difference when walking can be a little disconcerting. I've found the bounce is helpful to me even at the end of a marathon length run, when normally fatigue makes any shoe seem less cushioned than at the start. This cushioning is not without its issues however, and the Vaporfly feels quite unstable. It's like your foot is balancing on a ball rather than a block of foam. The height of the sole exacerbates this instability, and taking fast, tight corners requires some care. The instability also creates extra stress on my ankles, and I've found some discomfort around the Achilles, as well as tender calves.
  
  

  Comparing the Vaporfly with the Hoka Clayton.
• Drop. Normally the massive drop of the Vaporfly, which I measured at 12mm, would cause me all sorts of issues when running, but I've got on surprisingly well with it. Part of this might be that the 12mm drop is reduced to 8mm when worn, and might be even less under the impact of running. I have had issues with my heel scraping during the float phase of my stride, but this is not as bad as other shoes. If I'd have had to guess at the drop (something I can generally do fairly well), I'd have put the drop at about 4-5mm. That's more than I'd like, but not problematic.
• Structure. The structure of the Vaporfly comes from its carbon fiber plate. There doesn't appear to be any attempt to reduce pronation, and the carbon fiber plate actually seems to actively increase pronation. I have not dissected my pair, but it feels very much like the carbon fiber plate doesn't extend under the ball of the foot. Instead, it seems like the plate runs the full length of the shoe, but only under the four outside metatarsal bones. Towards the end of a marathon length training run the edge of the plate can become quite uncomfortable, and I've had some soreness from it. Under load, the ball of the foot is lower than the other four metatarsal heads, something I normally find when a shoe is worn out due to the midsole foam collapsing.
  
  

  This is the edge of the carbon fiber plate, which seems to be about the same on either side.
  
  
  

  From the side, the profile of the carbon fiber plate follows the purple line I've drawn, not the black line that you might expect.
• Flexibility. The Vaporfly's carbon fiber plate obviously reduces its flexibility. It's far from the least flexible shoe I've tested, but the carbon fiber plate makes it more of a spring, where most maximally cushioned shoes tend to be rigid. As noted above, I'm surprised how little I noticed the toe off spring. I've tested the VKTRY Insoles, which is an aftermarket carbon fiber plate that you can put in existing shoes. I found the benefits of VKTRY were hard to notice, but it's hard to detect things that can make a significant difference to your running performance. After all, 1% difference in running economy can be the difference between success and failure in a race, but I doubt you'd ever be able to perceive the change. The carbon fiber plate in the Vaporfly is fairly deep in the midsole, so there are no issues with it feeling hard under foot, which is a major downside to the VKTRY insole.
• Outsole. You can see the hard rubber outsole as the black areas on the sole of the Vaporfly. The outsole seems to be fairly hardwearing, and after some miles it's fairly grippy. It's not as good on gritty asphalt as the plastic nubs you get on Japanese racing shoes, but it's better than I expected. The outsole is placed so that most of the contact areas are protected, but there's still a lot of exposed midsole that's softer.
• Shape. The Vaporfly shape doesn't match the human foot, so the toe box compresses the toes. I found the Vaporfly is not as bad as most running shoes, but it did give me toe blisters until I cut open the toe box. (I recommend cutting open the toe box of virtually all running shoes, with the exception of a few shoes like some Altra shoes. When you have some worn out shoes, you should try cutting open the toe box. I've found that it's a big improvement, allowing my toes to move naturally and engage for toe off, as well as reducing the possibility of blisters.).
  
  

  The toe box cut open.
• Upper. The upper is nicely breathable and light weight. There's no padding in the upper except for around the ankle opening, though the upper material doubles over to support the laces. I've found the upper quite comfortable up to marathon distance (I've not run further than that in them so far.)
  
  

  The doubling over of the upper to form the eye holes for the laces.
  
  
  

  The upper backlit to show the breathability.
• Tongue. The tongue is a traditional style, without connections to the upper except at the base. It's thin and unpadded, but comfortable and I had no issues with pressure from the laces. I did find that the tongue tends to slip to the side a little, which is an annoyance, but nothing more.
  
  

  The tongue slipping to the side.
• Lacing. The laces work well and remained tied.
• Heel Counter. The Vaporfly has no heel counter, just the stiffness of the upper to keep it's shape.

2 Other Breaking-2 Shoes

Nike's highly publicized attempt to break the 2-hour marathon was documented in the National Geographic "breaking 2" (freely available on youtube.com). That failed attempt used the Nike Vaporfly Elite, a shoe you can't buy. This Vaporfly uses the same ZoomX foam and a carbon fiber plate in the midsole as the Vaporfly Elite. There is also the Nike Zoom Fly which looks superficially identical to the Vaporfly, but is radically different and vastly inferior.

3 Is It Really Faster?

A study "A Comparison of the Energetic Cost of Running in Marathon Racing Shoes" looked at the performance of the similar prototype shoe to the Nike Vaporfly. This study included researchers working for Nike, as well as the University of Colorado, and it used a shoe that not actually the Vaporfly, so use caution in interpreting the study. The picture below gives some insight to the construction of the Vaporfly, but also suggests some differences from the prototype which appears to have a full with carbon fiber plate.

The prototype Nike

The prototype was compared with the Nike Zoom Streak 6 (NS) and the Adidas adizero Adios BOOST 2 (AB). It's nice to see that they disclosed the actual shoes they compare it to. The researchers added small weights to the two Nike shoes so they were weight matched with the Adidas. A mechanical check showed that the prototype shoe was twice as well cushioned as either of the other shoes, deforming 11.9mm versus 6.1 and 5.9 mm. They prototype also had more bounce, returning 87.0% compared with 75.9% for the Adidas and 65.5% for the Steak. The study then compared the Running Economy of sixteen male high-level runners in the three different shoes. The runners have a VO2max of ~72, which is translates to a marathon time of about 2:20. They tested them at 14 kph (6:53 min/mile), 16 kph (6:02 min/mile), and 18 kph (5:22 min/mile), all below the Lactate Threshold of the runners (4 mmol/l, which is good enough for this study.) The running economy of the prototype shoe was 4% better than either of the other two shoes, which had similar running economy. The study noted that the prototype shoe was slightly better for rear foot landing runners (~4.7%) than the forefoot landing (~3.6%).

4 Update After 100 Miles

Normally, I would give an update on a pair of running shoes once I'd put rather miles on them. However, the vapor fly as something of a reputation for fragility, so I wanted to track its progress carefully. Even after this short distance, there is some evidence of the foam midsole braking down. If you look at the profile picture below, you can see some increases in the midsole appearing, and there is a noticeable indent under the ball of my foot. On the underside of the shoe, there is only a small amount of abrasion on the exposed foam. The hard rubber outsole (the black areas) are completely unchanged, suggesting that they are surprisingly hard wearing. The grip has improved over the course of the 100 miles. The main abrasion area on the exposed foam midsole is on the outside rear edge, where I occasionally catch my heel on steep descents. It should be noted that my running biomechanics are fairly efficient, and I'm typically quite gentle on my shoes. The upper is doing fine, even where I've cut open the toe box.

5 Update After 200 Miles

Over the last hundred miles I've come to really enjoy running in the Vaporfly. I've found my calf muscles have adapted reasonably well, and I've not had the ankle issues that I was fearing. My plantar fascia has been a little irritated, but nothing excessive. The foam midsole has continued to collapse, which is made the lack of support under the first metatarsal rather noticeable, and I can feel where the carbon fiber plate ends a little more distinctly. As you can see from the photos below, there's been remarkably little wear on the rubber outsole, and the exposed midsole is holding up pretty well. The Vaporfly is an awesome shoe for faster runs, but it does surprisingly well for Long Slow Distance. So, my initial thoughts of "awesome but awful" remain, and I'd still urge an abundance of caution as I think there is a significant injury risk to the vapor fly, but if you can handle the stress, and you can find a way to obtain a pair, I highly recommend it.

6 Update After 300 Miles

Another 300 miles have gone by quickly and pleasantly. The degradation of the Vaporfly has continued slowly, without any "falling off the cliff" that sometimes occurs. I've cleaned up the shoes a little more carefully for the photos below, and you can see that the midsole has a thin white plastic layer over the slightly more yellowed foam. The level of abrasion of the exposed midsole is surprisingly limited given the mileage. The black rubber outsole is even less abraded, and most of it looks entirely untouched. The midsole foam continues to collapse, but the collapse under the carbon fiber plate is far less than it would be without it. This means that the margin around the outside of the shoe where there's no plate is noticeably lower, and the area under the ball of my foot is depressed several millimeters. It's interesting when I swap back to "normal" running shoes. The extra support under the ball of the foot with fresh shoes is dramatic and feels really weird, but the big difference is how much I miss the spring of the Vaporfly.

7 A Comparison with other Recommended Shoes

If you're looking for "the best of the best" running shoe, here are my top picks. Of course, the answer will depend a little on what you're looking for, so I have recommendations for various categories. Best All Round Shoe. The Altra Escalante is my current all-round favorite. It has plenty of cushioning for its weight, it has a very springy midsole, it lasts well, and it has a shape that's closer to the shape of a human foot than most shoes. It's a great shoe for any runner, including those Starting to run. It's also a fairly easy shoe to find due to its popularity. Best Maximalist Shoe: If you want something massively cushioned, then I'd recommend the Saucony Kinvara 8. It's remarkably light and remarkably cushioned, beating Hoka at their own game. Best Optimal Shoe: For those looking to trade cushioning for speed, the Nike Zoom Streak LT 3 was my top pick, but the latest version (LT 4) falls short of it's predecessor. There are lots of great optimal running shoes, which provide just enough cushioning with light weight and minimal frills, but all have their weak spots. Probably the best option at the moment is the Altra Vanish-R, which offers great cushioning for just over 5oz/150g. Fastest Shoe: If you really want speed, then check out the Nike Vaporfly 4%. It's light, massively cushioned, and has a carbon fiber plate. Nothing comes close, not even the now defunct New Balance RC5000‏‎ or New Balance RC5000v2‏‎. There are a number of caveats; it's really expensive, it's really hard to find, and there's a significant injury risk. Best Minimalist Shoe: Merrell Trail Glove. I recommend the trail glove for road running in spite of the 'trail' moniker. It's not a fast shoe by any means, but it's comfortable and will last well. All Terrain Shoe. For trail running, I've become a fan of Altra, and I think their best shoe is the the Altra Timp, though the Altra Lone Peak is really close. Honorable Mention: It's not really a running shoe, but the Vivobarefoot Ra is comfortable, minimalist and can more or less pass as a dress shoe. I've worn mine to weddings with a suit and they've not looked out of place. You can run in the Ra, but the leather means it doesn't breathe well.

For a more detailed on running shoes see the Recommendations for Best Running Shoes. This table lists the key attributes of What to Look for in Running Shoes. For more detailed information, on the shoes see detailed shoe comparison.

It's not a running shoe, but I love the Hoka Tor Ultra hiking boot and I've tested the Altra Lone Peak Boot, the Hoka Tor Speed 2, and the Inov-8 Roclite 325 hiking boots
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