Kiprun KD900X 2 running shoe

Kiprun KD900X 2 upper

The upper of the Kiprun KD900X 2 running shoe is made from a thin engineered mesh with above-average breathability. The mesh is a stronger, more structured material that’s so thin it’s almost see-through. The whole upper is tuned more for performance than plush comfort. The tongue is thin, wider than average and wraps nicely around the midfoot, but it’s not gusseted, so it can occasionally drift to the side while running. The heel collar only has minimal padding and less structure, so it moulds nicely to the back of the foot and gives a comfortable, close fit. The upper runs long compared to the size chart: for my EU 42, the listed internal length was 26.5 cm, but in reality it’s 27.7 cm, noticeably longer than most other brands in the same size. That makes it hard to judge the true width of the upper; I felt it was on the wide side, but with the correct length I might not have found it as wide. As I mentioned, the upper is built for speed and performance, but the lockdown is not as strong as on other performance-oriented uppers. This isn’t really an issue on straight sections, but in sharper corners you can feel this limitation of the shoe.

Kiprun KD900X 2 midsole

The midsole of the Kiprun KD900X 2 running shoe is a full-length VFOAM compound with an embedded, curved carbon plate. VFOAM is a lightweight, very soft and extremely bouncy A-TPU foam. There are very few midsoles this springy and energetic. The carbon plate running through the midsole further boosts propulsion, and it’s much more flexible than in any other plated shoe I’ve run in (and I’ve tested quite a few carbon shoes). It reminds me most of the carbon plate in the Nike Zoom Fly 6, which also uses a thinner plate, but this one is even more flexible. You can bend and twist the midsole almost as if there were no plate in it at all. The shoe is primarily designed for faster paces, and the Kiprun KD900X 2 really shines on tempo runs and speedwork, but because it isn’t overly stiff, it’s also surprisingly comfortable at lower intensities and for easy runs – as long as you don’t go very long. Once you get past about 10 km, you do start to notice the plate and the shoe feels stiffer than an everyday trainer. The midsole platform has a medium width and the forefoot flex is not aggressive; there isn’t a very pronounced rocker geometry. A stronger rocker would help even more at race pace, but the shoe is still very quick as it is. Because the foam is softer than average and the plate doesn’t lock the shoe down into a very rigid feel, stability is only average. There aren’t many midsoles this good and this versatile – the Decathlon engineers have done an excellent job here.

Kiprun KD900X 2 outsole

The outsole of the Kiprun KD900X 2 running shoe covers a surprisingly large area of the midsole compared to other fast shoes or even full-on racers. The rubber almost completely covers the midsole, with just one cut-out on the inner midfoot, most likely to keep the shoe more flexible and shave a bit of weight. The rubber layer is thinner than average and the grooves are not very deep, but despite the slim profile, durability is excellent – wear resistance is well above average. Traction is also better than you’d expect from such shallow grooves; grip is definitely above average. At first glance the outsole looked a bit cheap to me and I didn’t expect much from it, but in practice it performs really well in both traction and durability.

Who is the Kiprun KD900X 2 running shoe for, and what type of runs is it best suited to?

The Kiprun KD900X 2 running shoe is a fast, lightweight neutral road shoe that’s ideal for race-prep workouts and your faster training sessions. Because it isn’t as brutally stiff as most carbon-plated super shoes, it doesn’t feel uncomfortable at lower intensities, but on longer runs you’ll definitely notice that this is a more rigid, performance-focused shoe. The upper is lightweight and highly breathable, built around speed rather than all-day comfort. The midsole is an absolute highlight: soft, light and incredibly springy with great energy return. The carbon plate is there more to add snap and responsiveness than to create a super-stable platform. Because the foam is so soft, stability is not its strong point. The outsole is also excellent, offering great grip and impressive durability. This shoe is primarily aimed at experienced runners for tempo runs, intervals and race-pace work; I wouldn’t recommend it for beginners, because it’s a lot of shoe and it wasn’t designed to be a comfort-first trainer. And because of the soft midsole combined with the carbon plate, I also wouldn’t suggest it for heavier or significantly overweight runners.