Nike Infinity Run 4 Review: A Softer, Heavier Update

Introduction

The Nike Infinity Run 4 is the first major update to the Infinity line in a few years, and it arrives with a completely new midsole that changes the feel of the shoe. It costs 155 pounds in the UK and 160 in the US, and it has gained noticeable weight: 346 grams (12.2 ounces) in a UK 9 / US 10, up from 310 grams in the previous version of the same size.

Under the foot there is a 9mm drop with 39mm of stack at the heel and 30mm at the forefoot. The big technical story is React X, a new foam with a lower carbon footprint than previous React. Nike describes it as softer, bouncier, and better at energy return, though it is also a touch heavier, which explains part of the weight gain.

Fit and Upper

The Flyknit upper is still here, but it has changed character. Instead of the old sock-like bootie feel, this is a thicker, more structured trainer upper with lots of small padding and overlay sections, generous padding around the tongue and collar, and a snugger overall fit than older Infinity models.

Sizing is the main talking point. Nike suggests going half a size up, and testers were split. One reviewer with a narrow foot found true to size worked well, with plenty of toe box room and a secure, locked-in feel. Another found the midfoot a bit sloppy at times during faster efforts or cornering. The practical guidance: stay with your normal size if you have narrow feet, and consider going up half a size if you have wider feet or tend to sit at the larger end of your size.

The big plastic heel clip from previous Infinity versions is gone, replaced by a small, flexible heel counter. The toe box has more room than before, thanks to a wider midfoot platform that keeps the shoe stable.

Ride and Midsole: React X Foam

React X is softer and plusher than the React foam used in the previous three versions, and the rocker geometry is retained on paper to keep the ride smooth. In practice, reactions diverged. One tester found the ride smooth, stable, and comfortable, with the rocker creating pleasant transitions, and felt the shoe worked fine even when picking up the pace on steady tempo runs and some lighter trail use.

Another tester found the foam stodgy and slow, with the foot sinking in and losing the snappy rocker transition that made earlier Infinity models feel smooth. At longer distances, that tester felt energy being sapped by the soft midsole, and preferred the firmer, more responsive ride of the Infinity 3.

The fair summary: this is a comfortable, stable, mileage-friendly ride that is not particularly lively. It is not built for speed work, and the extra weight shows if you push the tempo hard, but for easy miles and steady running it does its job.

Who Should Consider It

This shoe suits runners who want a stable, cushioned trainer to soak up a lot of easy mileage each week. If you are newer to running, or you just want a comfortable general-use shoe for the occasional run, the plush protection here is appealing.

It also has genuine crossover appeal: it is a good-looking shoe that works for casual wear and the gym, and one tester noted they would happily keep wearing it outside of running.

Outsole and Durability

The Infinity 4 gets a full outsole with a waffle tread, replacing the blotchy pattern of earlier versions. The intent is better grip and durability, and the Infinity line has always had a strong reputation for longevity, so expectations here are high.

Buying Advice

This is where opinions split most sharply. One reviewer called it their favorite Nike daily trainer of the year, praising comfort and consistency, and pointing to shoes like the Asics Gel Nimbus 25 as comparable “soak up the miles” options. Another considered the update a miss, arguing the shoe lost stability and responsiveness versus the Infinity 3, and recommending alternatives such as the Pegasus as a cheaper, more versatile option, the Invincible 3 for a livelier max-cushion ride, or cushioned rivals like the Asics Gel Nimbus 25, Saucony Triumph 21, and Puma Velocity Nitro 2.

The common ground is clear: if you loved the firm, stable, responsive feel of the Infinity 1 through 3, weigh whether you truly want this much softness. If you prefer softer everyday trainers and want maximum comfort for easy runs, this update may land better for you. And unless you are a dedicated fan of the line, the Infinity 3 remains a compelling alternative at a lower price.

Conclusion

The Nike Infinity Run 4 is a stable, comfortable, well-built trainer that trades some responsiveness and versatility for softness. Runners who want a plush daily trainer for easy mileage will find plenty to like, especially with the improved upper comfort and durable waffle outsole. Runners who valued the firmer, snappier ride of earlier Infinity models may want to stick with the Infinity 3 or explore alternatives. Know which type of runner you are before buying, and this shoe either becomes a reliable mileage partner or a shoe best admired for its looks.