If you’re looking for a cheap racing option which is light and snappy, the KD900X could be for you. It has a scratchy upper but is extremely durable and feels more natural than other super shoes due to its flexible carbon plate.
If you’re looking for a soft, cushioned super shoe which is propulsive and comfortable, look elsewhere. The KD900X falls short of most of the other super shoes in most areas.
The affordable carbon-plated super shoe isn’t a new concept. The 2 Hoka carbon-plated shoes (Rocket X and Carbon X 3) are both priced at $200 but the leader in this segment by a long way is Atreyu’s The Artist which comes in at a very attractive $100. The Artist however is only available to be shipped to a very few select countries.
Decathlon is a French sporting goods retailer which operates in over 65 countries, making it one of the largest sporting goods retailers in the world. Kiprun is one of Decathlon’s very own in-house running brands.
I’ve never run in a pair of Decathlon trainers. I have tried various models in the store and they have all felt firm, flat and not very comfortable.
The KD900X is Decathlon’s first high performance running shoe for both training and competition. It’s equipped with a Pebax midsole and a full-length carbon plate.
They state on their website that one of their athletes ran a time of 1 hour and 2 minutes in the KD900X in the Lille half marathon which is lightning fast. They also advertise the shoe’s durability, stating that one tester ran 1200 km in it so it sounds very promising.
The KD900X weighs 7.8 oz (221 g) for a men’s US9 with stack heights of 37 mm in the heel and 29 mm in the forefoot so it has really competitive specs.
My pair cost 575 Malaysian Ringgit which when converted is 125 USD so you’re basically getting a carbon-plated racer for the price of a daily trainer.
My first run was a 20 kilometre weekend run at a moderate pace. In the first half of the run, I must have stopped about 8 times to redo the laces because the fit felt so uncomfortable.
I had to use a runner’s knot to get a secure lockdown but at the same time, the forefoot felt too tight so I had to keep loosening the bottom of the laces. The bottom of the tongue where it’s connected to the upper also felt very uncomfortable: it poked into the top of my foot for the entire run.
The ride did feel fast. The carbon plate felt very flexible compared to other carbon plates so the KD900X didn’t feel as stiff as other super shoes but the forefoot still felt very snappy. It was easy to increase my speed below 4 minutes 30 seconds per km (for short bursts) and transitions felt smooth. It didn’t feel as fast as a top-tier racing shoe though because there was no rockered ride and there was no strong springboard propulsion.
The ride also felt very firm- the firmest running shoe that I’ve run in all year. This is surprising considering the midsole is Pebax and Pebax is normally softer than EVA/TPU foams.
I still managed 20 kilometres but I was glad that the run wasn’t any longer. It wasn’t a great first run impression.
The KD900X upper is horrible;
there is no other way to put it. It feels really cheap and scratchy, even for a $125 running shoe- it’s by far the worst upper I’ve experienced on a running shoe. I spent so much time trying to adjust the lacing to get a comfortable fit during every single run because the front of the shoe is so narrow while the toe box ceiling is very low.
The tongue which is flat and not gusseted has wings which fold when you put the shoe on, so you have to stick your fingers into the lacing area to uncurl the tongue sides or else it won’t lie flat against the top of your foot. The stitching where the bottom of the tongue is attached to the upper pokes into your foot if you don’t wear really thick socks. I’m not sure how they didn’t pick this up during the testing of the shoe.
There is no heel counter but there’s no heel slippage so long as you use a runner’s knot. The upper mesh is very breathable but I had to wear really thick socks to protect my feet from the rough upper so I didn’t benefit from the porous mesh.
The sizing is off. It runs long so you have to go down a half size at least. It has a really narrow forefoot and toe box so I don’t think it’s suitable for wide footed runners.
Decathlon partnered with a French chemicals company named Arkema to create the midsole foam which they named VFOAM. It consists of tiny pellets which have been compressed and glued together, similar to Saucony’s PWRRUN PB which is also a Pebax foam.
It’s no surprise that it feels like PWRRUN PB underfoot but a firmer version of it. It doesn’t compress much and it doesn’t provide much rebound so it doesn’t possess much long-distance comfort.
The ride is firm and it has plenty of ground feel; it reminds me of old school racing flats like the Takumi Sen 7 and I struggled to find the willpower to put mileage onto the KD900X because it has such a bland, flat ride. Even though it has a high stack height of 37 mm in the heel, the KD900X feels like a medium stack shoe because of how firm and unresponsive the VFOAM midsole is.
When it comes to design, I can see what the designers were trying to go for. They wanted a “Vaporfly”, springboard type of propulsion but there are 2 main reasons why the KD900X falls short and doesn’t feel as fast.
The KD900X is only suitable for fast paces below 5 minutes per km (8:03 minutes per mile). Easy runs are not comfortable because of how firm it rides so it’s not a versatile shoe.
Stability is also not great due to how narrow the midsole is so it’s definitely not a shoe built for slow running. I mainly used it for tempo runs and interval workouts but it’s not as fun to use as the more expensive super shoes because I had to work harder to increase my pace.
The thin insole is glued down in the forefoot but not in the rearfoot. When I pulled it out to air it, the place where it was glued down in the forefoot ripped a small chunk out of the bottom of the insole so now there’s a piece missing from the insole. That’s the kind of low quality that you have to deal with in the KD900X.
The outsole of the KD900X is the highlight of the shoe for me. The entire forefoot is covered with thick rubber and the high wear areas on the rearfoot are also protected with thick rubber. The midfoot doesn’t get rubber protection but the foam is so tough and abrasion-resistant that it doesn’t need coverage on the midfoot section.
After the testing period, there is some discolouration on the midfoot foam section but the rubber shows very little signs of wear so I can easily see this outsole lasting over 1000 kilometres- it’s very impressive for a racing shoe.
Traction in the KD900X is also decent. I ran after it had just rained and I didn’t have any problems with grip on tar, concrete and wood surfaces.
$125 for a carbon-plated racer is cheap but you have to put up with a lot of caveats: the upper is extremely uncomfortable, the ride is not as propulsive as other super shoes and it isn’t really suited to distances beyond a half-marathon. Is it worth the price? I don’t think so.
I’m disappointed with the KD900X because for a company as big as Decathlon, they could have done a much better job with the amount of resources they have. The KD900X feels half-baked and rough around the edges; it still feels like a prototype.
I won’t be using the KD900X in my rotation. It’s too firm for racing a full marathon and as a training shoe, the upper is so uncomfortable that I can’t wait to take it off everytime I wear it.
If you want a carbon-plated shoe which feels similar to a flagship super shoe, the Magic Speed 2 is your best option.
It has the stiff carbon plate, rigid midsole and a fantastic upper. Yes, the Magic Speed 2 is slightly more expensive but you get what you pay for. You get a much higher level of cushioning with better long-distance comfort.