If you’re a runner with strong ankles and you want a fast shoe with no ground feel, the Prime X Strung is the shoe for you. The Prime X can feel unstable at slow paces but feels fast and propulsive when you pick up the pace.
If you’re a runner who needs stability and you enjoy fast shoes with minimal rides, then the Prime X Strung is not for you.
Now, New Balance also has one in the SC Trainer and ASICS has one in the Superblast so it looks like the jumbo stack height trend is not a fad; it’s here to stay. The Prime X stands the tallest with a gargantuan 50 mm stack height.
When I reviewed the original Prime X last year, I was blown away by its aggressive rocker and its fun, experimental ride. I had never before experienced any super shoe this cushioned, efficient and unstable.
The Prime X is an example why World Athletics banned shoes taller than 40 mm in stack height or with more than one rigid plate or similar device in its midsole. I concluded in my review that the Prime X does give you an unfair advantage over regular super shoes.
When I first ran in the Prime X, I found it extremely unstable- a sensation similar to walking on stilts however the more I ran in it, the more I got used to it and the stronger my ankles became. Over the past year, I have regularly worn the Prime X for tempo runs and interval speed workouts. It’s by far the most fun super shoe in my collection.
I really enjoy how the extreme rocker throws you forward at toe-off and how much lightweight cushioning the Lightstrike Pro midsole provides. There’s no other shoe like it on the market.
The one weakness of the Prime X was its upper, specifically the lacing area. I found that there wasn’t enough padding to protect the top of my feet from the eye stays at the bottom of the lacing area so it caused uncomfortable pressure.
The Prime X Strung is only an upper update. The new Strung upper is a new textile innovation from Adidas. The Prime X Strung weighs 255 g (9 oz) which is heavier than the original version which weighed 251 g (8.9 oz). The Prime X Strung costs a jaw dropping $300 which is $25 more than the last version. In Malaysia, the Strung version costs the same as its predecessor.
The first time I saw the Prime X Strung, it reminded me of the Nike Alphafly Next Nature which is also an expensive super shoe with an advanced, experimental upper. When I reviewed the Alphafly Next Nature, I felt that the new upper didn’t offer any advantages over the original and it cost more so it didn’t make sense to me.
My first run in the Prime X Strung was a strength workout consisting of 2 x 4.8 km intervals. The ride felt exactly the same as the previous version and I really enjoyed the workout. It felt cushioned, very fast due to extreme rocker, and slightly unstable at slow paces.
The new upper felt a lot more comfortable than last year’s version. It conformed to my foot better, felt softer and didn’t have the poking sensation on the top of my feet from the eye stays.
The Prime X Strung felt a lot bigger and bulkier than the Adios Pro 3 which I’ve been using recently. It felt less streamlined and more like a training shoe due to the thicker outsole rubber and the comfortable upper.
At first, I was skeptical about the innovative Strung upper but I can now say that it has improved the Prime X and I prefer it to the plastic-like, Celermesh upper of version 1.
The upper consists of partially recycled threads which are individually placed and concentrated where more structure and support is needed on the upper. There are tiny holes between each thread but breathability is not as good as the original Prime X.
The flat tongue is attached on both sides so there’s no tongue slide and they’ve also fixed the uncomfortable eye stay problem of v1. The eye stays now stick outward so there’s no irritation on the top of the foot.
The heel tab can either be worn up or down. I mostly fold mine down so that I don’t feel it against my achilles. There’s no heel counter but heel lockdown is still very good and I didn’t get any heel slippage. There are padded strips on the inside of the collar so the area around the ankles feels comfortable- the original version didn’t have these pads.
The fit of the Prime X Strung is very roomy but I still recommend going true to size. The forefoot and toe box are spacious so it feels comfortable and like a training shoe upper. Wide footed runners should be fine in the Prime X Strung.
There are 2 factors which make the Prime X Strung illegal for official World Athletics races; these 2 factors are also what make the Prime X Strung so unique and fun to use. It has a midsole which measures 50 mm in the heel (10 mm above the limit) and it has 3 additional carbon blades below the Energyrods to make the forefoot extra stiff.
I wouldn’t recommend the Prime X Strung to you if you haven’t used a super shoe before or if you have weak ankles because it has a very narrow rearfoot and midfoot so stability could be an issue. It’s for those runners who are used to super shoes already and who want additional cushioning/efficiency without the stability.
In the New Balance SuperComp Trainer, another jumbo above 40 mm stack height super shoe, your foot sits inside the midsole so it doesn’t feel unstable. In the Prime X Strung, your foot sits above the midsole- there are no midsole sidewalls or other stability elements.
I use my Prime X Strung for intervals of any distance, as well as tempo runs and faster long runs so it’s fairly versatile- as long as you’re running faster than 5 minutes per km (8:03 per mile). The Prime X Strung shines most when you’re up on your toes and engaging the rocker, that’s when it feels the most efficient and energy-saving.
The midsole of the Prime X Strung is made of pure Lightstrike Pro so there’s no shortage of cushioning depth. I find Lightstrike Pro to be one of the most balanced super foams: it’s not overly squishy (like NB’s FuelCell) and it’s not brittle (like Nike’s ZoomX). It feels incredibly energetic and bouncy with excellent durability.
Unlike the Adios Pro 3 with full-length Energyrods, the Prime X Strung still maintains a carbon plate in the heel with Energyrods in the midfoot and forefoot which are not connected to the carbon plate. Ride transitions are still very smooth and you can’t feel the plate or rods underneath your feet because they are buried underneath so much midsole foam.
The Prime X Strung doesn’t feel extremely propulsive like some of the other super shoes with aggressive carbon-plated setups. It feels fast because it’s so efficient and energy-saving; it’s smooth and effortless, not punchy.
The Prime X Strung has an outsole which is more durable than the average carbon-plated racer. The Continental rubber is thick and the exposed midsole foam is very durable- it doesn’t scuff or chip easily. Grip is very good in wet weather because the forefoot outsole rubber is ribbed.
The Prime X Strung is an improvement over last year’s version. Its upper no longer digs into the top of your foot and it’s made of a softer, more flexible material which makes it much more comfortable.
Is it worth $300? I don’t think it is. There are cheaper options for $250 which are lighter and more versatile. The Prime X is however (in my opinion) the most fun, fast shoe you can buy.
It features the most heavily rockered ride on a running shoe ever so it feels extremely efficient and it has a ridiculous amount of cushioning which keeps your legs fresh on any distance. There’s a reason why such tall racers were banned from competition and once you’ve run in the Prime X Strung, you’ll understand why.
I wouldn’t recommend the Prime X Strung to runners who are looking to buy their first super shoe: it’s much too tall and unstable. I would recommend it to you already have a carbon-plated racer and you’re looking for a supplementary durable, fast trainer that you can do workouts or long runs in.
You can also race in the Prime X Strung if you’re not a professional runner who competes in World Athletics events. I might do so for my next marathon.