Nike React X Infinity Run 4 vs Infinity Run 3: First Run Impressions

Introduction

The Nike React X Infinity Run 4 is the first major redesign of the Infinity line since it launched. Its purpose stays the same: a stable neutral shoe with lots of cushioning, aimed at easy runs and newer runners who want a protective, comfortable feel underfoot.

Nike’s changes are significant. The React X midsole is the headline, the upper has been reworked, and the shoe has grown wider and heavier. We ran both the new model and the Infinity Run 3 to see whether the redesign actually improves the ride.

First Run Impressions: Nike React X Infinity Run 4

The new midsole is React X, which Nike says has a lower carbon footprint than standard React foam and delivers an extra 13 percent of energy return. On the run, it feels softer and squishier than the older React, though the promised bounce is not obvious. Landing feels like sinking in rather than popping back, which makes the shoe feel bottom-heavy at speed.

The spec sheet shows why. In a UK 9 (US 10), the Run 4 weighs 345 grams or 12.2 ounces, a big jump from the 310-gram Infinity Run 3. The stack height is 39 millimeters at the heel and 30 millimeters at the forefoot, giving a nine-millimeter drop. Cushioning at the heel and midfoot feels generous, but the forefoot feels noticeably less plush, and the cushioning seems to run out quickly at the front of the shoe.

Fit and Upper

The upper is Flyknit with heavy padding around the collar and tongue, and the big plastic heel clip from earlier Infinity models is gone, replaced by a small internal heel counter. Nike says the inside is water resistant, enough to keep puddle splashes from soaking your feet on wet runs.

The fit is wider than the Run 3, especially in the toe box, which no longer tapers aggressively. Wide-footed runners should get on better with this version. Tester feedback on sizing split: one runner found their normal size slightly snug and suggested sizing up if you are between sizes, while another went true to size with room to spare. Nike itself recommends going half a size up on some sizes, so checking fit carefully is worth it.

The shoe also looks genuinely good. The design is clearly different from previous versions while keeping the pronounced rocker, and it presents a cooler-looking package overall.

Ride and Foam Feel

This is a shoe built for easy paces. Sprinting or picking up the pace gets little from the foam, and cruising comfortably while enjoying the heel cushioning is where it works best. The wide base and big sidewalls of foam keep the foot sitting within the midsole, and the base is even wider around the midfoot than before, so stability has not been lost.

On short runs, the cushioning feels protective and the ride is comfortable. Over longer distances, heel strikers rolling through to the forefoot may notice some fatigue at the front of the shoe.

How It Compares to the Infinity Run 3

Wearing both shoes side by side, the older Infinity Run 3 still wins in several ways. Its firmer React foam gives a smoother transition and works better with the rocker geometry, letting you settle into a rhythm across a wider range of paces. Its upper is one of the most pleasant we have experienced on any shoe, especially for narrower feet.

The Run 4’s softness and squishiness work slightly against its rocker, so you sink in and lose some of that rolling sensation. The trade-off is real: React X is a nice foam with a lower environmental footprint, but the ride does not yet clearly benefit from the changes, and the weight gain is substantial.

Where It Fits in Your Rotation

If you love the Infinity Run 3, you will like this. It keeps everything that defined the line: the rocker, the React-family foam and the Flyknit upper. As an everyday shoe, though, its 345-gram weight and calm ride put it up against softer, plusher alternatives, and it is priced at $160 in the US, the same as the previous model, with a jump to £155 in the UK.

Within Nike’s own range, there are shoes with a stronger identity. The Invincible is far softer and springier, and the Pegasus is cheaper while offering a livelier, more versatile ride. The Infinity Run 4 sits in between, which makes it best suited to runners who specifically want a stable, heavily cushioned easy-day shoe from the Infinity line.

Conclusion

The React X Infinity Run 4 is a good-looking, stable, well-cushioned everyday trainer that has not yet shown a clear improvement over its predecessor. The extra width helps wide-footed runners, the stability is intact, and the React X foam is promising, but the added weight and muted energy return hold it back. Fans of the Infinity line will still find a lot to like; everyone else should weigh the alternatives first.