The upper is your foot’s first line of defense against weather, dirt, and abrasion.
Strategically placed plastic or fabric “exoskeletons” reinforce the foot in vulnerable areas to add support. When connected to the lacing system, they can also enhance fit.
Like a car chassis, the midsole sits between the upper and outsole to absorb shock, support the foot, and reduce fatigue. Molded EVA and polyurethane foams provide lightweight cushioning, while thermoplastic polyurethane (TPU) plates or shanks act like extra foot bones to bear weight and provide critical support for heavy loads.
The rubber outsole protects the bottom of the foot and grips the trail.
Knobby lugs provide traction.
The tongue gusset provides a seal between tongue and boot to fend off water and trail debris.
The heel counter, made of rigid materials sandwiched between the upper and the inner lining, surrounds the rear of the boot to stabilize the heel.
A rubber rand boosts durability in high-wear areas and creates a waterproof seal between sole and upper.
Membranes between the upper and boot liner, such as Gore-Tex or eVent, make boots waterproof and breathable.
Boots made of waterproof leather (rather than a membrane) have stitches treated with seam sealer.
The cutout ankle collar known as an Achilles notch is a must for anyone with tendonitus or Achilles discomfort; it also helps relieve Achilles pressure on long descents.
A rockered (curved) sole allows for natural striding.
Ridges provide crampon compatibility.