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Footwear

Shank

What is a shank in a boot?

A shank is a stiffening insert running through the arch of a boot, made of steel, nylon or composite. It controls how much the boot twists and bends, which is what lets a boot support a heavy load and edge on rock.

Shank at a glance

Half shank
Day hiking, light loads
Three-quarter
Backpacking, 30 lb and up
Full shank
Mountaineering, crampons

What a shank resists

Hold a boot by the toe and heel and try to twist it. What resists you is the shank, an insert laid under the arch between the midsole and the outsole. It's the single biggest determinant of how supportive a boot feels.

Full, three-quarter and half shanks

Boots get described by how far it runs. A full shank stiffens the whole length and is what crampon-compatible mountaineering boots use. A three-quarter shank stiffens most of the foot and suits heavy backpacking. A half shank supports the arch while leaving the forefoot free to roll, which is the usual arrangement in a mid-height hiking boot.

Why stiffer is not more supportive

More stiffness is not more support in any useful sense once you pass what your load needs. A stiff boot resists the ground rather than following it, which is what you want under 40 lb on scree and is tiring and clumsy on a flat trail with a daypack. Match it to the weight you carry rather than to the terrain photos in the advert.

What this means when you're choosing

  • Full shank only if you need crampon compatibility or carry very heavy loads
  • Three-quarter or half for general backpacking, which most people want
  • How the boot resists twisting when you hold it at toe and heel

The common mistake

Buying the stiffest boot available

Past what your load needs, stiffness stops being support and becomes work. A stiff boot resists your foot rolling through the stride, which is tiring on easy ground and does nothing useful under 30 lb.

Common questions

Do I need a shank in a hiking boot?

For loads under about 25 lb on maintained trail, not really, which is why trail runners work fine for a lot of hiking. Above that, or on loose rock where you're edging, a shank stops your arch doing work it isn't built for.

Are steel shanks better than composite?

Stiffer and heavier, and mostly confined to mountaineering boots now. Nylon and composite shanks give hiking boots the stiffness they need at a fraction of the weight, so steel is a specification rather than an upgrade.

Where this comes up

Guides on Tom's Hiking where shank changes which product is right for you.

Going deeper

More in footwear

Lug depth

Lugs are the raised blocks on the sole of a boot or trail shoe, and lug depth is how tall they are, usually 3 to 6 mm. Deeper lugs bite into soft ground; shallower ones give more contact area on rock and hard trail.

Outsole

The outsole is the rubber layer on the bottom of a shoe, the part touching the ground. It carries the lug pattern and the rubber compound, which together decide grip, and it's usually the first part of a shoe to wear out visibly.

Midsole

The midsole is the foam layer between the outsole and your foot. It absorbs impact and sets how stiff or soft a shoe feels, and it's the part that quietly dies long before the tread looks worn.

EVA foam

EVA is the light, springy foam most hiking and running midsoles are made of. It cushions well and weighs little, but it compresses permanently over time, which is why shoes go flat after a few hundred miles.

Stack height

Stack height is how much material sits between your foot and the ground, measured in millimetres at the heel and forefoot. More stack means more cushioning and less ground feel; less means more feedback and a lower, more stable platform.

Heel-to-toe drop

Drop is the height difference between a shoe's heel stack and its forefoot stack, given in millimetres. Zero drop means the foot sits level; 8 to 12 mm tilts you forward slightly and shortens the load on the calf and Achilles.

Rock plate

A rock plate is a thin stiff sheet, usually TPU or a nylon composite, embedded in the forefoot of a shoe. It spreads the load from a sharp rock across the whole foot instead of letting it press into one point.

Rand

A rand is a strip of rubber bonded around the lower edge of a boot's upper, most often at the toe. It takes the abrasion from rock and roots that would otherwise wear through fabric or leather, and it protects your toes from impact.

Gusseted tongue

A gusseted tongue is sewn to the sides of the boot with fabric panels instead of hanging free. It seals the gap along the laces so grit and water can't get in, and it stops the tongue sliding sideways as you walk.

Vibram Megagrip

Megagrip is a Vibram rubber compound formulated for grip on wet and dry rock. It's softer and stickier than standard hiking rubber, which is why it holds on slabs and greasy roots, and why it wears out faster.

Gaiters

Gaiters are fabric sleeves worn over the top of a shoe or boot to keep grit, snow and water out. Low trail gaiters cover the collar and stop scree filling your shoes; tall gaiters run to the knee and seal the leg against deep snow and wet brush.

Microspikes

Microspikes are elastomer harnesses with short chains and spikes, roughly 10 to 15 mm, that stretch over a shoe for traction on packed snow and ice. They are the middle rung between yaktrax-style coils and full crampons, and they are not mountaineering equipment.

Crampon

A crampon is a metal frame carrying 10 or more points up to 5 cm long that binds rigidly to a stiff-soled boot, so a climber can stand on hard alpine ice and steep snow. It is the tier above microspikes, and it is technical equipment that needs an ice axe and training.

Insulation weight in grams

Insulation weight is the mass in grams of one square meter of the insulating sheet inside a boot or glove. A 400g boot uses a heavier sheet than a 200g boot, so it is warmer, but it is nothing like twice as warm.

Vibram Arctic Grip

Arctic Grip is a Vibram outsole technology built for traction on wet ice. It stays pliable at temperatures where ordinary hiking rubber goes hard, which is the reason a winter sole grips where a three season one skates.

Flotation

Flotation is how well a snowshoe keeps you on top of snow instead of sinking into it. It is a function of deck surface area measured against your loaded weight, which is your body plus clothing, boots and everything in your pack.

Heel lift

A heel lift is a small wire or plastic bar behind the heel of a snowshoe that flips up so your boot rests on it during a climb. It stops your calf being held at full stretch on sustained steep ground.

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