Nike InfinityRN 4 Review

Nike didn’t change much in the first three generations of the Infinity running shoe, and while it was never a particularly exciting option, the Nike Infinity Run 3 was a stable and durable cushioned shoe that was a solid option for easy and long runs.

A lot has changed with the Nike InfinityRN 4, including the mildly annoying way the name of the shoe is styled. A new ReactX midsole changes the feel of the shoe and, for the most part, not in a good way. The InfinityRN 4 falls short of the standards of the best running shoes, and while it may have appeal as a crossover lifestyle/casual running shoe, better cushioned running shoes are not hard to find.

Nike InfinityRN 4 Review: Price And Availability

The Nike InfinityRN 4 launched in July 2023 and costs $160 in the US and £155 in the UK. This is a price rise of £10 in the UK from the launch price of the Nike Infinity Run 3, while the US price has stayed the same. Within Nike’s range of cushioned shoes it’s cheaper than the Nike Invincible 3, but more expensive than the Nike Pegasus 40.

How I Tested This Shoe

I’ve run 25 miles (40km) across four runs with the Nike InfinityRN 4. Three have been easy runs outdoors with the longest being just shy of 10 miles, and the other was an interval treadmill session. I’ve also tested every generation of the Nike Infinity Run line, along with most Nike running shoes and a wide range of the best cushioned shoes on the market.

Design and Fit

The biggest change to the Nike InfinityRN 4 is the midsole, which is now made from ReactX foam instead of the React material used in previous versions of the shoe. Despite the minor name change, ReactX is significantly different from React: softer, bouncier and more environmentally friendly. Using ReactX instead of React has reduced the carbon footprint of the midsole by 43%, according to Nike.

That all sounds great, but another difference is that ReactX is heavier. Along with other changes to the shoe, this results in the InfinityRN 4 gaining weight compared with its predecessor. The shoe now weighs 12.2oz/345g in my UK size 9, up from 10.9oz/310g in the same size for the Infinity 3. Weight isn’t everything with running shoes, but this is one of the heaviest road running shoes I’ve tested.

The InfinityRN 4 has a stack height of 39mm at the heel and 30mm at the forefoot for a 9mm drop, and it’s wide too, which helps ensure it’s still stable despite the high stack of soft foam. While the new shoe doesn’t have the large external plastic heel clip used in previous models to create stability, the InfinityRN 4 does have sidewalls of foam within which your foot sits to add support. As with previous Infinity models, the shoe has a rocker design to roll you onto your toes.

The Flyknit upper is well padded around the tongue and collar and has a snug fit, to the point that Nike recommends going half a size up. I found the shoe fitted me well in my normal size, but I have a narrow foot, so if you have a wider foot then going for the bigger size may be advisable.

I found that while the upper held the foot well at the heel, the midfoot was sloppy and my foot slid around laterally at times during runs. This was especially the case when rounding tight corners or running at speed. I’d prefer more support around the midfoot, which the older Infinity shoes did provide.

The shoe has a full rubber outsole with a waffle pattern, which gripped well for me and looks like it will be highly durable. The Infinity line has been renowned for its durability up until this point, though part of that is down to the longevity of React foam and it remains to be seen if ReactX can live up to that precedent.

Running Performance

While I never truly loved the Nike Infinity line, it was a shoe with a clear purpose: to be a stable and long-lasting option with a smooth, rockered ride. The firmer feel of React foam complemented this role, and although it wasn’t an exciting ride, the Infinity worked well for easy and long runs. It was a shoe I’d often use in the latter stages of a long marathon training plan because the stability and rockered ride was great for rolling through easy runs on tired legs.

The InfinityRN 4 is a much softer shoe, and while it does also have more bounce, there isn’t enough springiness to counter the mushy feeling of the foam. Your foot sinks in and then the rocker is negated and you don’t get much bounce back off your toes. The result is a sluggish ride that doesn’t feel great even for easy runs longer than five or six miles because the shoe almost starts to sap your energy.

On shorter runs it felt fine, though it’s not a quick shoe because of its weight and the slow transition from heel to toe. The midsole protects the legs well and heavy runners will appreciate the high stack of cushioning, but it is also less stable than previous models.

Is The Nike InfinityRN 4 Worth It?

I don’t think the Nike InfinityRN 4 is an improvement on the Infinity Run 3, with the new midsole making the ride less smooth and enjoyable. It’s a good-looking shoe that may appeal to those who want a shoe to use for the odd 5K run, as well as lifestyle use. However, if you want a cushioned shoe for more extensive use, there are better options.

Within Nike’s range, I much prefer the Nike Vomero 17, which has a comfortable ride but is much more versatile than the InfinityRN 4. The Nike Pegasus 40 is much cheaper and a better shoe for any type of run as well, though not as soft as the InfinityRN 4. If it’s softness you’re after, however, then the Nike Invincible 3 delivers that, with a soft and springy ZoomX midsole that’s more impressive than the ReactX used in the InfinityRN 4.

Outside Nike’s range you can find better cushioned shoes for less than the price of the InfinityRN 4, like the Puma Velocity Nitro 2. If you want a max-stacked cushioned shoe then the Asics Gel-Nimbus 25 is much more enjoyable to run in, and the Saucony Triumph 21 is a comfortable and more versatile option.