Adidas Adizero Prime X Strung 3.0 Introduction

With sub 6 oz (170 grams) racers becoming the norm, is there still a market for a racer that weighs 70% more? With a gigantic 50 mm heel stack height, it’s impossible for the Adidas Prime X to weigh as little as a legal long-distance racer.

I’ve raced about 8 marathons since the Prime X was launched and I’ve never seen one pair being used in a marathon. Yes, it’s illegal for official World Athletics races but even so, that won’t stop amateur runners from using it if it provides enough speed assistance.

The Prime X is one of the few illegal, carbon plated racers currently on the market. The other similar product is the PUMA RB Nitro Elite which is 58 mm in the heel but it’s a lot more expensive and a lot harder to buy than the Prime X.

2023’s Prime X 2 was the heaviest Prime X to date. It was also the most stable version. It provided a really high level of speed assistance but its 10.4 oz (295 g) weight cancelled out a lot of the speed assistance. I never used it for racing- only intervals and long runs at moderate paces.

Will the Prime X ever be light enough to race in? Version 3 weighs 9.9 oz (281 g), substantially lighter than version 2. It measures 50 mm in the heel and 43 mm in the forefoot (the same as v2). It also costs $300, the same price as v2.

Adidas Adizero Prime X Strung 3.0 First Impressions

My first run was an all out 10K race. My first thought was how aggressive the rocker felt. It was the most aggressive forefoot rocker I’ve ever experienced. The toe spring felt much higher than in v2.

The other thing I noticed was the softer ride. The foam felt a little more squishy than the foam in its predecessor. As a result of this, the stability also felt lower.

I was able to run close to 39 minutes which wasn’t a personal best but it was only a few seconds off. I started off fast but by the 7th kilometre, the substantial weight of the shoe had started to slow me down.

I raced another 10K two weeks prior to this in the Alphafly 3 and I found that it was much easier to maintain a fast pace towards the end of the race in the lighter Alphafly.

Adidas Adizero Prime X Strung 3.0 Upper

The Strung material is hard and it doesn’t stretch at all. It’s innovative but I wish Adidas would use the standard Micro Fit material that the Adios Pro 4 and Adios 9 use. There’s no advantage using Strung over regular mesh.

It’s a bootie construction but unlike v2, you can’t tie a runner’s knot. Foot lockdown is still very good though. The Strung material isn’t as soft as v2 and it doesn’t conform to your feet as well. Breathability is average.

I recommend buying your normal size. The fit is very narrow up in the front and on one occasion when I wore thick socks, the narrow toe box squeezed my feet so much that I got uncomfortable rubbing between my toes. It’s not a shoe for wide feet.

Adidas Adizero Prime X Strung 3.0 Sole Unit

The Prime X 3 has very high top end speeds. When I’m leaning forward and pushing down hard into the road with my toes, I achieve speeds that I can normally only dream of. The only caveat is that I can’t hold that pace for long periods due to the 9.9 oz (281 gram weight).

The ride of the Prime X 3 is closer to the Adios Pro 3 than the Adios Pro 4. It has a firmer ride than you’d expect for such a tall midsole of Lightstrike Pro. I do wish that it was a bit softer and more squishy because the ride feels harsh with the stiff plate being so close to the foot.

The entire midsole of the Prime X 3 is made of Lightstrike Pro but the layer above the plate and the Energy Core are a softer, lower density foam (the same as in the Adios Pro 4). The bottom layer is the older, firmer Lightstrike Pro.

The Prime X 2 had no Energy Rods (only 2 plates) but in the X 3, they switched back to Rods like in the Prime X (original) and the Prime X Strung (version 2). The big difference in the X 3 is that the carbon plate is on top and the rods are below it.

Adidas say that this distributes the pressure more evenly across the layers beneath the plate but in reality, it makes the ride harsher. The rods are supposed to be closer to the foot so that they can move vertically independently, along with your metatarsals.

Even though it has 50 mm of foam in the heel, I can’t run long distances in it. The combination of the plate and Energy Rods make it extremely stiff with absolutely no flexibility. The longest run I did was 24 km and it wasn’t a comfortable one. The stiff plate being so close to the foot doesn’t feel pleasant during long runs.

All the components of the Prime X 3 don’t quite seem to gel together. The extreme stiffness, the soft top layer and the firmer bottom layer all feel like they aren’t working together to deliver a cohesive ride.

When it comes to stability, the Prime X 3 is unstable but it’s not extremely unstable like the Mizuno Wave Rebellion Pro or the HOKA Cielo X1 2.0. I have to slow down when cornering or when running on uneven surfaces but it doesn’t kill my ankles when doing medium or long runs in it.

Traction is great in all weather conditions. It has also been upgraded to Lighttraxion rubber like the Adios Pro 4 and it still has Continental in the forefoot for grippy toe offs.

Durability is decent but not as good as the Prime X 2 which had a firmer midsole foam. I can see some wear in the middle of the rearfoot on the areas not protected by rubber.

Adidas Adizero Prime X Strung 3.0 Conclusions

The Prime X 3 is a fun shoe to use with its extreme forefoot rocker that propels you forward but it wasn’t the update I was hoping for. While it is softer, faster and more aggressive, it’s still too heavy for racing.

The high level of speed assistance is cancelled out by its substantial weight. It’s also not comfortable for long runs because of how the foams and plate/rods are set up.

It doesn’t quite feel as polished as the previous versions which were still heavy but had smoother, more comfortable rides. They need to make the next version lighter by changing to a traditional upper and they need to use Lightstrike Pro EVO foam in a portion of the midsole to reduce the weight.

$300 is a lot considering there are faster, cheaper options for marathon racing. It’s a very niche offering which most runners won’t be able to find a place in their rotation for.

The cheaper Adios Pro 4 is much lighter and holds fast paces much easier. The EVO SL is a long run alternative which feels more comfortable and is half the price of the Prime X 3.