Performance and Durability in One Great Sport Climbing Shoe: Ocún Sigma Review

Czech climbing brand Ocún might not be on your radar, but its new shoe, the Sigma, proved why it should be. The aggressive, high-performance lace-up shoe was perfect for those looking to send harder projects outdoors.

I tested the Ocún Sigma for months inside and outdoors on rugged Iowa limestone, primarily on sport routes, as that’s the shoe’s target discipline.

In short: For sport climbers with narrow to normal feet, the Ocún Sigma is a great performance shoe with strong edging capabilities and durable construction.

Ocún Sigma

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Specifications

• Upper material: Microfiber
• Midsole: 3D Fit Hard dual layer
• Outsole: 4mm Vibram XS Grip rubber
• Closure: Lace
• Available sizes: 4-13 UK

Pros

• Excels at sport climbing on vertical and overhung terrain
• Comfortable given the aggressive fit
• Vegan

Cons

• Not a shoe for those with wide feet
• Tongue bunches and catches when putting on shoe

Mary Andino

Ocún Sigma Spec Sheet

The Ocún Sigma offers a split-sole design that extends the 4mm Vibram XS Grop sole almost all the way to the heel. This provided greater support for the arches than a typical split-sole climbing shoe. The upper is made of synthetic microfiber, with a generous swath of 3D rubber covering much of it.

The single-piece mesh tongue delivered plenty of breathability, and the laces are placed slightly off-center on the shoe. This allowed me to tighten them without placing uncomfortable pressure on the bridge of the foot. The Ocún Sigma in size 39 weighs a verified 17.1 ounces per pair, and the MSRP is $180.

Ocún Sigma Fit

As someone with narrow, Egyptian-style feet (large taper from big toe to little toe), I found this climbing shoe to fit quite comfortably. The heel was extremely secure, with no gaps or space. The toebox is comparable to other aggressive sport climbing shoes: tight and narrow, but not uncomfortably so.

Testers with wider or Greek-style feet (second toe longer than the big toe) found the shoe more difficult to size properly and more challenging to wear for more than a few minutes. Ocún recommended to me that users size half a size down from their street shoe size for the Sigma, but I found that 1 to 1½ sizes down provided a better fit.

Ocún Sigma Performance

The Ocún Sigma required a minimal break-in period. After a couple of sessions, it stretched out slightly and felt comfortable to wear for extended periods of time.

While the partially mesh tongue provided good ventilation, it also continually snagged and got bunched up while putting on the shoe. While not a major knock, this was not a shoe that I could just jam my foot into and throw on; the tongue required a bit more precision and attention. 

Pocket Pulling and Edging

I tested the Sigma on vertical, overhung, and slab routes both indoors and outdoors. The aggressive downturn of the toe performed extraordinarily well on pockets, allowing me to dig my toe into even the smallest offerings. The stiffness of the shoes meant edging was precise, even on polished, untrustworthy limestone. I felt secure standing and foot-switching on the most minuscule of holds at my local gym.

Smearing, Heel and Toe Hooking

The stiffness and edging prowess of the Ocún Sigma, unsurprisingly, did not translate to exceptional smearing. The lack of sensitivity made it middle of the road when it came to smearing and slab work.

The heel’s sturdiness and secure fit, however, made heel hooking a lock. The heel structure felt significant, even compared to La Sportiva’s Solution shoe. Although the robust construction limited sensitivity, I confidently cranked on high and challenging heel hooks without pain.

The shoe’s specially designed 3D toe patch made it easy to pull in and maintain tension on toe hooks. Like the heel, the rubber toe patch was rather robust, toning down the sensitivity but allowing hard hooking without foot pain.

Final Notes on Performance

Ocún uses Vibram’s XS Grip rubber for the outsole. Most climbers I know consider it inferior compared to the stickier, more durable XS Grip 2. It’s worth noting that this rubber, however, is only available on La Sportiva and SCARPA’s performance shoes.

As someone who normally wears La Sportiva’s Katanas outside, I appreciated the Sigma’s better breathability and offset laces. On a hot July day, I found my feet sweating less in these climbing shoes than in the Katanas. I typically yank on my lace-up shoes for as tight a fit as possible, and the Sigma’s lace placement made it less painful to do so.

The generous arch support made the Sigma a shoe comfortable for projecting and working out beta for long periods, rather than a shoe to wear only on redpoint attempts.

Finally, the Ocún Sigma proved to be durable, with no substantial degradation after extended use. The rubber’s extension up to the bridge of the foot and beside the laces means that the upper was well-protected while jamming or scraping up against rough rock.

Conclusions on the Ocún Sigma Climbing Shoe

If you’ve got narrow feet and are in the market for an aggressive, durable sport climbing shoe, the Ocún Sigma is an excellent choice. The Sigma caters to those with a strong foundation of technique and who are looking to push into higher outdoor grades.

It’s worth noting that at an MSRP of $180, it is $30-50 cheaper than other comparable aggressive sport climbing shoes, like the La Sportiva Katana ($220) or the SCARPA Instinct ($210).

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