For indoor bouldering this soft and super-sensitive shoe has a lot going for it, says Rob Greenwood; but it's seriously let down by an issue that many climbers may never even have considered before.

Red Chili feel like they've been progressively upping the ante with their climbing shoes in recent years. The improvements probably started with the Voltage, which we reviewed back in 2019, and have continued ever since. The Sensor brings all of that design and development work into a single top-end shoe. Initial impressions were pretty positive: it certainly looks the business, is well made, fits (me) well, has plenty of rubber around the toe... but - and it's a big BUT - there's a catch. We'll come onto that shortly.

In Use

The Sensor is designed primarily with indoor bouldering in mind. As the name suggests this is the most sensitive shoe in Red Chili's range and is ideal for pasting rubber onto the most marginal of footholds and the most abstract of volumes.

It's a very soft shoe, with a minimalist midsole, but it does have some support around the front, partly from a fairly thick 4mm Vibram XS Grip, which prevents it from folding/creeping on edges. As a result it's a remarkably good all-rounder from a performance perspective, particularly whilst indoors and on steep terrain. Outdoors it would be quite a specialist shoe, but if you are pushing your grade on harder/steeper terrain, then the Sensor might well be suitable in specific applications.

But now for the catch. This can be summarised in three words: line - of - sight.

When you're looking down at your foot, something that's important - but often goes unremarked - is your ability to see where your edge is and place it on the hold accordingly. I would say this is critical, because it allows you to be precise with your foot placements, and no matter how strong you are with your arms, good footwork is vital.

This is where it feels like something has gone wrong in the Sensor's design process, because whilst everything else ticks the box, this quite essential need has not been met. Instead the edges curve away quite significantly underneath the shoe. This is most noticeable around the inside and outside edges, where it's overlapped quite significantly by the rand, so you can't see where it is. As a result, it's really, really hard to place your foot precisely because you don't know exactly where the edge is. Whilst this is something that could obviously be learned, there's always going to be an element of guesswork. 

Fit

The Sensor is at the narrower end of the spectrum and designed to be worn quite tight, with your toes knuckled up against the end. I sized a whole size down from my street shoe size (8.5 > 7.5), but found that to be a bit too tight, at least to begin with. Whilst they did wear in, I think I'd have been better off going a half size down, which is what I'd recommend anyone else do unless they're after a super precise fit. Once they're on they fit like a slipper, but with the bonus of a single, solid strap. The heel feels fairly high volume, but not so much so that it slips off during use, due to the fact it's got a fair amount of tension coming through it in order to push your toes to the front.

Features

There's a nice, generously size toe patch across the front of the shoe, which is both thin and soft so that it doesn't interfere with the shoe's comfort. Due to its relatively slender cut it's remarkably sensitive and you get a lot of feedback through it whilst toe hooking or scumming, which makes it great to climb in.

The Sensor also features a sock lining. This adds to the comfort, but it's extremely lightweight, and where it appears throughout the sides of the shoe it does feel like it'll wear quite quickly. Mine already has holes developing and whilst it isn't critical to the shoe's performance, nobody wants a shoe that feels like it's falling apart!

Summary

In many ways I really like the Sensor. It fits well, it's well made, and seems like a step up from previous Red Chili shoes; however, the issues regarding line of sight are too significant a factor in terms of its performance, as it's very difficult to get a precise foot placement when you're left guessing where the edge on your shoe might actually be. For me, unfortunately, this is the decider.