In this product guide:
- 1. Flexible daily trainer without a heel counter: Nike Flex Experience 12
- 2. Cushioned marathon racer without a heel counter: adidas Adios Pro 4
- 3. Cushioned marathon racer without a heel counter: Saucony Endorphin Pro 4
- 4. Flexible daily trainer with a collapsible heel: Nike Free RN 2018
- 5. Flexible daily trainer with a collapsible heel: Nike Free Run 5.0
- 6. 10K/5K racer without a heel counter: Nike Streakfly 2
- 7. Speed Trail shoe without a heel counter: Hoka Zinal 2
- How we selected
The Flex Experience 12 is inspired by the Nike Free. Like the Free, the deep flex grooves of the midsole make the shoe very easy to bend, allowing the foot to flex naturally. The foam midsole is also cushioned enough for everyday runs and in-gym use.
The midsole isn’t the only thing the Flex Experience borrows from the Free. The soft mesh upper is an exercise in deconstructed minimalism, so the lack of an internal counter makes the heel fully collapsible.
Many things have changed on the Adios Pro 4, but the upper still has a soft and collapsible heel. The forefoot update includes a softer mesh, attached tongue, and tweaked lacing for a smoother fit.
What else is new for this year? The highlight of the Pro 4 is its softer and bouncier foam. This version of Lightstrike Pro feels livelier and more fun to run in. There’s a noticeable springiness that was missing on the previous version. The rocker midsole has been fine-tuned to produce a stronger roll-forward effect. It’s easier to roll off the foot than the Pro 3; the bouncier foam also helps. On the flip side, the softer heel – which includes a deep cavity that wasn’t there on the Pro 3 – makes the shoe far less stable. Take note, heel strikers and heavy runners. The long-term durability of the softer midsole is also currently unknown.
The changes aside, our verdict is that the Adios Pro 4 is an excellent marathon racer. The super-foam midsole delivers the ride experience that a runner expects at this price. The 39 mm and 33 mm stack heights provide all the comfort a marathon needs. The thin Lighttraxion outsole is also new for 2025. The lugs on the soft rubber outsole grip well, even on damp surfaces.
- adidas’s marketing pitch: Designed to optimize running efficiency.
- Upper: Lightweight mesh with attached tongue. Semi-collapsible heel.
- Midsole: Full-length Lightstrike Pro foam with Energy rods. 6 mm heel drop.
- Outsole: Continental and Lighttraxion rubber.
- Weight: 200 gms/ 7.05 Oz for a half pair of Men’s US 9/UK 8.5/EUR 42.5/CM 27.
- Stack heights: 39 mm (heel), 33 mm (forefoot).
- Available widths: Single, D – regular (reviewed)
- Previous model: adidas adios Pro 3.
- Country of origin: China.
- Recommended use: 10K, half-marathons, marathons.
- Footstrike orientation: Midfoot/forefoot (full contact).
- Orthotic compatibility: No.
- Median lifespan: 400 miles.
- Recommended paces: Quicker than 5:30 min/km (8:50 min/mile).
- Recommended temperature range: Warmer than -0° C/32° F.
Pros
- Soft and bouncy comfort
- Propulsive rocker effect
- Outsole traction
- Upper comfort
- Speed-friendly ride
Cons
- Unstable heel
- Long term durability is unknown
- No optional width(s)
The Saucony Endorphin Pro 4 is comparable to the Nike Vaporfly 3, because of its similar form factor and materials. Like Nike’s signature racing shoe, the Endorphin Pro 4 has an S-curved Carbon plate inside a PEBA foam midsole. The Endorphin Pro blends snappy responsiveness with a cushioned ride. While it’s been completely redone for 2025 with a brand-new midsole and upper, it has the same qualities that made the first three versions successful.
The ‘hanging’ end of the plate makes the rearfoot snappy, whereas the stiff forefoot rocker helps with quick transitions. The high-volume PEBA midsole makes high-mileage runs less punishing on the feet. This being a racer, the upper strips away unnecessary components – and that includes a stiff heel counter. It’s worth mentioning that the Endorphin Pro 4 offers better stability than the Speed 4 because of the latter’s (more flexible) Nylon plate.
Seven years after its release, the Nike Free RN 2018 is still going strong. We can see why; it’s the next best thing to our favorite Nike shoe – the 2014 Free 4.0 Flyknit. The lightweight mesh of the one-piece upper creates a distraction-free fit experience. The large pores on the forefoot and tongue also allow the air to circulate. And of course, the elastic heel can be folded completely flat.
This 7.5-ounce shoe isn’t just about the soft heel. The dual-density midsole is extremely flexible and comfortable enough for runs up to 10K. This makes the Free RN 2018 an ideal running shoe for travel.
The Free Run 5.0 is Nike’s modern interpretation of the flexible shoe concept, but it stays true to its roots. The EVA foam midsole is generously grooved for a high level of flexibility, and the sock-like upper has a soft yet snug fit.
There are meaningful differences between the Free RN 2018 and Free Run 5.0. The newer model isn’t as deconstructed, and has a narrower fit due to the last shape and sock-like entry. The heel is lined and padded with foam for comfort, but is completely foldable as it lacks a heel counter.
The Streakfly 2 isn’t meant for everyday mileage. It’s designed to go fast, preferably at speeds of 4:00 min/km (6:30 min/mile) and faster with forefoot striking. This lightweight racing shoe has a full-length carbon plate for heel-to-toe stiffness; it behaves like a track shoe, but for the road. The ultra-stiff forefoot has zero flexibility, so the Streakfly 2 is limited to landings and take-offs. The waffle rubber outsole and midsole rocker enable faster speeds.
The two layers of ZoomX foam make the Streakfly 2 comfortable enough for up to a 10K. For a minimalist racer with a lightweight upper and tight fit, the heel is surprisingly comfortable. The heel collar is padded with a thick foam pocket, while the absence of a stiff counter keeps the pressure off the Achilles.
Here’s a unicorn. Really. We have never come across a trail-running shoe without a solid heel counter. But as they say, there’s always a first time. The Hoka Zinal 2’s soft counter allows the heel to fold over itself. This heel design is fitting for the Zinal, given how minimal the rest of the shoe is. This is one of the lightest trail running shoes on the market, and the minimal upper design helps the Zinal achieve its 8-ounce weight. The heel opening is an elastic sock-like entry, and fused overlays add some durability over the upper.
The low-to-the-ground EVA midsole is attached to a Vibram Megagrip outsole with 5 mm lugs. Since the New Balance Summit Unknown, there haven’t been many low-profile trail shoes, so the Zinal 2 adds value to the outdoor footwear landscape. If you wanted a lighter and softer version of the Saucony Peregrine, but with a collapsible heel, then the Zinal 2 is the shoe.
How we selected: What to look for
Most running shoes have a reinforced heel for a good reason. A molded counter addresses a couple of performance needs. Unless the shoe is poorly designed, an internal or external counter minimizes heel slippage during runs. A stiff counter also locks the foot over the midsole. Without a supportive heel, the foot could push through the back (during uphill sections), and that will affect the ride quality and may also cause blisters.
Standard daily trainers like the Asics Nimbus 27 use a hard heel counter.
However, stiff heel counters are an ancient feature that arrived long before running shoes did. It then transferred to the earliest versions (think the 70s and 80s) of board-lasted running shoes, because at the time, running shoes were built using dress shoe techniques.
On most running shoes, a hard heel counter works together with the padded collar to make the heel fit better.
Heel stiffeners were indispensable before high-performance fabrics (like Nike Flyknit) were invented. In modern times, a secure heel fit can be achieved just through knit uppers alone. For example, elastic mesh uppers like adidas Primeknit and Nike Flyknit grip the heel extremely well. Also, textiles with different stretch (or non-stretch) properties can be used together to create a snug heel fit. Like everything in life, the merits and drawbacks of a heel-less running shoe can be debated ad infinitum. Nonetheless, this being a buyer’s guide for running shoes without a heel cup, we’ll focus just on the advantages.
A running shoe without a heel counter is an excellent recovery shoe
Running-related injuries like Achilles Tendonitis can be frustrating. While a running shoe without a hard heel counter doesn’t make the recovery process quicker, it certainly makes it more comfortable. A running shoe with a foldable heel is less likely to create a pressure hot spot. A soft heel counter is particularly helpful for runners with Haglund’s deformity, also known as ‘pump bump’.
A running shoe without a heel cup is easier to wear
There’s something freeing about a running shoe without a hard heel cup. Some running shoes like the Nike Free Run 5.0 and Free RN Flyknit 2018 have a semi slip-on upper, so you can leave the laces in a fixed position and take advantage of the elastic heel to slip on the shoe. This way, you don’t have to fight the laces every time you wear the shoe.
A running shoe with a soft heel means distraction-free comfort
Heel counter or not, the modern approach to designing a running shoe is rooted in minimalism. Just a decade ago, a typical running shoe upper was crowded with stitched and fused overlays. The midsole had various cushioning inserts and plastic shanks. Today, a running shoe has a knit upper with very few seams. The sole design now relies on superior foam materials rather than layering and clunky TPU shanks. As a result, the upper fit is smoother and so is the ride quality. The moral of the story is – the fewer the components, the lower the probability of irritation. The same applies to heel counters as well.
A running shoe with a collapsible heel is travel-friendly
A running shoe with a collapsible or foldable heel has a huge advantage during travel. It can be packed nearly flat to save precious space inside a checked bag.
(Related read: The best running shoes for travel)