I still climb in the original Instinct S, even 13 years after the slipper hit the market. I'm down to my last two pairs: a beat-up pair of 41s with holes in the uppers and a pair of pristine 40.5s that I'm keeping under glass for a project this autumn. For me, the Instinct S (and the original lace) were the perfect shoes: friendly to wider feet but still with a vacuum fit, precise with a knack for staying put on even the smallest holds, and so big-toe-focused that they essentially changed the way I climb. I used the semi-stiff slippers on long, technical pitches, often to my climbing partners' befuddlement: "You're using slippers on an edging climb?"
"Yes. Yes, I am," I'd say. "Get used to it!"
I don't do well when I can't feel the holds, climbing tentatively on thin face where everyone else is sporting TC Pros, Boostics, or Katana Laces. So sure, my calves probably tire out more quickly in slippers, but being able to sense the rock underfoot makes me climb with greater confidence.
I was initially excited when the Instinct S was redesigned into the Instinct SR (version 2.0), a beefed-up Instinct S on steroids, with more scumming rubber and a turbo heel. And I did like them--at first. But I never quite found a home for them like I had for version 1.0; the fit was odd (boxy/clunky) and they felt more niche, less all-around. I still use them, but mainly for vertical face with flat edges and pockets, like at Ten Sleep, and the occasional cavey pitch. They just weren't the same shoe. So it was with some fear, and my own unconscious (alright, conscious) bias that I began testing the new Instinct S: Would they measure up?
Slippers, Slippers, Slippers...
First off, you have to dig slippers to dig the Instinct S. If you're a "slipper dabbler," these aren't for you--they're soft and yielding. However, if you don't mind trading some calf and foot fatigue for top-tier sensitivity, then read on.
I've been climbing in slippers since the original slippers, the La Sportiva Ballerina--designed, like the Instinct S, by Heinz Mariacher--came out in the 1980s. Hell, I even climbed in those weird slippers (I can't recall the name) that had a rubber-strap heel rand you could toggle on and off, but that almost always slid down when you were hooking. Perhaps it was these early dalliances that trained me to love slippers and that strengthened my feet, to adapt. We did a lot of bouldering, and even though it hurt to hit the ground in slippers, I loved being able to feel the rock, whether it was on the crystalline granite blobs of the Sandia foothills or the insane steeps at Hueco Tanks, featuring oppositional smears and iron-rock razors. Given that most alternatives back then were stiff-ass hightops, slippers worked better.
The new Instinct S is a classic entry into that genre: It's all about the feedback.
Break In Will Take Awhile--So Stick With It
The new Instinct S were "interesting" out of the box. They're extremely flexible from fore to aft--you can bend the shoe in half in either direction. But they were also unyielding in the forefoot itself, despite using a thin half sole (3.5 mm) of softer XS Grip 2 rubber. So I was confused: Where was I supposed to use them? For my first few times out, mostly on vertical to gently overhanging granite sport, they did feel clunky, especially for smearing, and I had flashbacks to the Instinct SR. But then they broke in.
As the weeks wore on, the shoes conformed more to my foot, the sole got scuffed and bendier, and I wore an impression in the soft Alacantara leather toe patch over the big toe (inside the footbed) that let me drive harder and harder into the toebox. I began to like, then to love, the Instinct S.
I first noticed this shift on a project at a secret crag in the Front Range foothills, on a traversing, bouldery line that overhangs 40 to 50 degrees. There is a move in which you have to grab hard with your right foot on a squarecut edge to keep your hips in, then cautiously bring your left foot up to a credit-card inset, toeing into it to bap your left hand from a sloping jug to a flat pinch and set up for a sideways throw. It's a wild move that's all about body tension and footwork. Boom: The Instinct S locked me in, with optimal grabbing on the right foot and precision toe pressure on the left, and all the feedback I needed to sense my position on the holds. For what was essentially roped bouldering, they were the ideal shoe. The switch to the dual-elasticity/hardness-rubber CTS rand, which keeps the harder Ilga rubber on action zones like the inside rand and heel strip, and uses the softer M50 rubber (it comprises the perforated patches) where the shoe needs to flex, meant superb performance--a perfect blend of power and flexibility--on bouldery terrain.
Slabs, Hooks, and Beyond
A few weeks after that, my buddy Brandon and I put up a long "slab" climb on the knob-studded granite of the Monastery, near Estes Park. The Instinct S ended up being my redpoint shoe on the line, which features a gently overhanging V8 scoop to a smorgasbord of endless vert and off-vert standing: smears, knobs, crimps, dishes, nubbins.
Honestly, they worked better here than the Instinct Laces, which are meant to be more of an all-arounder but were a hair stiff for the varied footwork. On one clip, you stand on a knob with one foot and post down into the barest nipple with the other to get into balance: It's a test of trust and foot pressure, but also sensitivity. It was at that point, as I confidently made the clip, that I realized I loved the new Instinct S. I'd used them on both a super-steep and a super-slab, and they'd been, well, super. The one ding would be that the toebox is not as sharp as the original or as the Instinct VS or Lace, though it's still plenty sharp for workhorse edging and for the all-around use I'd been tasking them with. Anyway, given that most climbers may use the Instinct S primarily for bouldering and cavey sport climbs, not thin face, I'm not sure how much this will matter.
On a final note, I love the creative footwork solutions afforded by slippers, with their low cut and agile feel. But many slippers fail by being too minimalist: Their nearly all-leather or all-synthetic upper doesn't give you enough purchase on the rock for jessery. The Instinct S, however, is loaded up with exterior rubber: the stiffer Ilga and the perforated M50 in both blue and black hues. I took them back to the swell at our secret crag a final time to play around with heel hooks and scums. It was a trip how well they did here. I could hook on basically nothing--like a smooth patch of rock under a roof--cam my toe in opposition, and lock in. All that lateral, torsional, and fore-to-aft flexibility had the shoes bending and deforming like a second set of hands. These are "clever" slippers, and you'll need to rise to the occasion to figure out how to use them.
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