Kiprun KD900X 2 Review: An Affordable Carbon Speed Shoe That Punches Above Its Price

Introduction

The Kiprun KD900X 2 sits at the more affordable end of Kiprun’s carbon shoe range, which also includes the LD version aimed at long-distance running and the Kiptorm Lab, the brand’s new pinnacle racing shoe. Priced at £120-£130 and currently reduced to under £100 in the UK, it promises a full-stack carbon-plated ride at a fraction of the cost of most premium racers.

We put it through a demanding first test: a double-threshold day with 10 x 1k reps in the morning and a 10k steady tempo effort in the afternoon, close to 30k of running in total.

Specs and Construction

The KD900X 2 uses a full stack of 40 mm at the heel dropping to 32 mm at the forefoot for an 8 mm drop, and it is very lightweight at 205 g (7.2 oz) in a UK 8.5 / EU 43 / US 9.5.

The upper is a very thin mesh with a thin tongue, light padding around the heel, and a small internal heel counter. The midsole is V foam, believed to be an aliphatic TPU, with a full-length carbon plate running through it. Rubber coverage extends the full length of the shoe with a small cutout in the middle, so heel and forefoot are well protected, which bodes well for durability.

First Run: A Double Threshold Test

The first session was 10 x 1k reps at under 3:25/k pace with 60 seconds recovery, roughly marathon pace for those efforts, run in the dark on an early start.

The shoes feel good. They do not have the aggressive sink-in and bounce of some super shoes, feeling more like an earlier generation of carbon-plated design, with a lightweight and nippy character. They turn over very quickly, feel light and natural on the foot, and are quite stable for a carbon shoe. It is essentially a classic lightweight speed shoe with modern additions of fancy foam and a carbon plate, giving a modest amount of assistance without discomfort.

The second run, a 10k steady tempo in the afternoon, was smooth and controlled. The shoe stayed responsive even on tired legs, and it proved as protective as some higher-stacked super trainers now exceeding 40 mm or softer super shoes. Around 30k in a single day, the legs felt reasonably good afterwards, which suggests real protection from the platform.

Fit and Sizing

Sizing runs small. The tested pair went half a size down from normal UK size, an 8.5 UK where the usual size is 9, and also a half size down on EU sizing (a 43 instead of a 43.5 or 44). Using the centimeter measuring tool on the brand’s site is the most precise route, but as a general guide, go half a size down.

The fit is excellent: good room around the toes, a secure hold around the heel and midfoot, and a simple, lightweight upper. Kiprun uppers have occasionally felt firm in past shoes, but this one has no pressure points, with soft, flexible material around the lacing area. It is very comfortable for a lightweight, speed-focused upper.

How It Fits Into a Shoe Rotation

There are two ways to look at this shoe. The first is as a replacement racer for premium models, most of which cost over £200. For A-races, dedicated racing shoes like the Asics MetaSpeed Sky Tokyo or the Kiptorm Lab may still have the edge, but the KD900X 2 delivers a very high level of performance at a much lower price.

The second, and arguably more compelling, use is as a value speed trainer. Shoes like the Hoka Mach X3 or Asics Megablast offer more versatility across run types, but if you already have an easy-day shoe sorted and need a dedicated speed trainer for your rotation, the KD900X 2 is faster thanks to its lightweight, racy design, and considerably cheaper.

Things to Consider Before Buying

Early testing suggests this is not a big all-rounder. It feels very dedicated to speed and does that job very well, so it is best suited as a workout and racing shoe rather than a daily easy-run option.

Longer runs are still untested, and further testing is planned to compare it directly against a full-blown carbon racer in the same session. Based on early testing, though, it may be the strongest option in the Kiprun range tried so far in terms of value for the performance delivered.

Buying Advice

If your rotation already covers easy days and you want an affordable shoe to absorb your speed sessions, this is one of the most sensible options available right now. If you are hunting for a budget race-day shoe for faster events, it also fits that role well. Check the under-£100 sale pricing in the UK if you can, and use the centimeter sizing guide for the best fit.

Conclusion

The Kiprun KD900X 2 is a fast, light, poppy carbon-plated shoe that held up impressively over nearly 30k of hard double-threshold running. It does not have the wild bounce of the newest super shoes, but its quick turnover, stable ride, solid protection, and outstanding value make it a genuinely exciting option for speed training and racing alike.