Surface Tension

Part 0:
Before Rubber

Written by Leah Balagopal

In this installment of Surface Tension, we’re going back to the beginning of footwear. Long before Vibram or 3D-printed midsoles, people were already looking to the animal kingdom to figure out how to stand where others slipped. Hooves, paws, hides and fibers became the first blueprints for grip – an early attempt at engineering before the word even existed. Farmers, hunters, monks and mountaineers were copying what they saw in goats, seals, and predators, mocking up ways to take the human race to new levels.

Before rubber took over our soles, grip was borrowed from the animal kingdom, the blacksmith’s anvil, and the farmer’s rope pile. For thousands of years, human traction on steep or slick surfaces depended not on chemistry, but on a mix of leather, plant fiber, bone, iron, and ingenuity. If the goal was to stand where others slipped, the answer lay in mimicking nature’s specialists – goats bounding up granite, seals hauling themselves up ice, and predators padding silently across rough terrain.

This prehistory of technical footwear isn’t just a quaint prelude but rather the blueprint that still shapes how we think about traction today. Many of the design principles we now consider "modern" were there long before polybutadiene and nano-silica.

1. Hooves and Fibers

Long before biomimicry was a term, mountaineers, shepherds, and hunters were reverse engineering the anatomy of the animals that outclimbed them. The goat’s hoof was perhaps the most envied natural climbing tool: a hard outer rim for edging, a concave mid-section for surface contact, and a cloven split that allowed micro-adjustments on uneven rock.

In the highlands of Central Asia and the Middle East, goatskin climbing slippers emerged as a literal extension of this thinking. Soft, supple hides hugged the foot, the textured grain providing subtle friction on rock. Sherpa and Tibetan climbers used similarly tight fitting hide shoes for scrambling over dry, weathered granite. They wore quickly, but the tactile precision they allowed prefigured the close-fitting climbing slippers that would reappear centuries later in modern rubber.

At the other end of the temperature spectrum, Arctic and subarctic cultures turned to sealskin. In ski skins, strips of hide with the hair left intact naturally lay in one direction, allowing a ski or foot to glide forward yet grip when weight shifted backward. It was the earliest directional tread, an asymmetric friction pattern that outdoor footwear brands now re-create with precision molded lugs.

If hooves were the blueprint for edging, paws inspired early concepts of friction surfaces. Hemp rope sandals in Japan, Spain, and the Andes had a coarse texture that worked much like an animal’s rough toe pads. On dry rock, the fibrous surface gave enough bite to prevent slippage, while the woven structure flexed around uneven terrain. In Japan, waraji sandals bound from straw or hemp were worn by everyone from farmers to foot soldiers, and for mountain ascetics climbing sacred peaks, they offered a tactile link to the ground, a literal feel for the rock that even the best modern rubber tries to preserve.

One of the most sophisticated of these tactile shoes was the Japanese jika-tabi that emerged in the early 20th century. These split toe boots combined the sensory feedback of a paw pad with a hard-wearing sole, making them ideal for climbers, farmers, and construction workers alike. The split allowed the big toe to operate independently, improving balance and precision on small holds and became a functional echo of the cloven hoof that has had a history of iterations and continues in the Tabis of today.

Not all pre-rubber solutions relied on hides or hemp. In coastal and river environments, anglers and ice walkers used felt soles to grip on slippery rock and ice. The material’s tangle of fibers created high surface area and micro-level interlocking with rough textures. In the mountains of Siberia and Scotland, felt soles were used on hunting boots for silent, grippy movement over icy ground. This was an early lesson that softness could be a form of traction, a concept that would come roaring back with sticky rubber.

Similarly, in southern Europe and North Africa, esparto grass sandals were prized for their ability to cling to hot, dry rock. The coarse, slightly abrasive fibers provided dependable friction where metal would have skated.

2. Iron Foot 

In Europe’s mountains, leather was the upper of choice, but the sole was often a canvas for blacksmithing. Hobnails–short, conical iron pins hammered into the leather outsole that provided bite in turf, mud, and soft snow. They turned a smooth sole into a studded traction device. The Scottish and Tyrolean boot traditions used hobnails in patterns that balanced grip with walkability, the nails driven just far enough to avoid bruising the foot.

By the early 20th century, Tricouni nails took things further. Invented in Switzerland, they were serrated steel cleats that bit into rock, ice, and hard snow. Unlike round hobnails, Tricounis had multiple sharp edges, working almost like miniature crampons. The design addressed a problem climbers still face today, optimizing grip in multiple directions without clogging or wearing unevenly.

In some cases, climbers blended nails and early spikes, creating hybrid soles with larger protrusions for mixed terrain. This was the era of "performance at any cost" grip was king, even if it meant scarring the rock or tearing up floors indoors.

Across the Atlantic, Pacific Northwest loggers developed caulk boots, also known as corks. These heavy leather boots with steel spikes threaded directly into the sole were designed for climbing wet, bark-covered logs and steep, mossy hillsides. Their aggressive bite was overkill for most mountain travel, but the concept of replaceable, terrain-specific sole hardware would later influence approach footwear and crampon integration.

3. Resin to Rubber

By the 1930s, as mountaineering became more specialized, climbers began experimenting with resin-coated soles. Leather was brushed with pine pitch or varnish to create a tacky layer, a crude, temporary "sticky rubber" that worked for a few pitches before wearing off. Italian and French alpinists also developed canvas-and-rope hybrids for warm, dry rock, where the combination of a flexible upper and textured sole offered better smearing than stiff nailed boots.

These experiments were the awkward adolescence between animal and mineral and the very beginnings when climbers were primed for a chemical breakthrough, even if they didn’t yet know what form it would take.

By the late 1930s, the limits of pre-rubber solutions were obvious. Nails slipped on wet rock, hides wore through, fibers rotted. Climbers were ready for something that could combine softness, precision, and durability,  the same wish list that fuels climbing shoe design today. When Vitale Bramani introduced the Vibram Carrarmato in 1937, he wasn’t inventing grip from scratch. He was distilling centuries of animal mimicry, rural craft, and blacksmith ingenuity into a new material vocabulary.