Hiking boots are designed to give the best possible off road performance, with robust uppers to protect the feet and support the ankles, soft cushioning insoles for comfort, and midsoles for shock absorption and rigidity; however it is the outsole design which will keep you on your feet and get you powering over tough terrain.
Whilst the outsole may not be one of the primary considerations when purchasing hiking boots, its construction has a significant bearing on performance. Hiking boot companies invest considerable resources into developing highly technical designs to give the best possible traction, and formulate rubber blends to stick to soft ground and have the durability to cope with abrasive and punishing surfaces. Choosing hiking boots with an outsole to match the terrain you plan to cover can have a significant bearing on the lifespan of your hiking boots, and will also ensure that you have the traction to cope with your preferred terrain.
The blend of rubber for hiking boots is vital for providing traction, with sticky rubber the best for coping with soft, wet ground. Vibram is the best known performance rubber manufacturer, and is widely regarded as the best. The soft and sticky blends are ideal for low level trails and for heading off road and for hill walking, although there is often a trade off between stickiness for traction and hardness for durability. Blending rubber with other compounds and varying the density helps to provide better durability for dealing with tougher terrain. Carbon rubber is a popular choice for the toughest hiking boots, which offers a much harder wearing composition better suited for highly abrasive terrain.
Tread pattern plays an important role in traction and lug placement and tread patterns are highly technical. The function of the outsole is to generate friction across a wide variety of surfaces and conditions, and the lug placement has an important bearing on grip. The function of outsole lugs is to sink into soft ground and increase the surface area in contact with the terrain. Multi-directional lugs provide the maximum traction on slippery surfaces, with precise angles to give maximum bite and to prevent slippage. Hiking boots tend to use wide tread patterns to prevent clogging and adding to the weight which needs to be carried, whilst ensuring each foot placement has clean contact. On harder ground and on slick surfaces, contact area is minimal and creates pressure points on the outsole, and the rubber blend needs to be robust and rigid to cope, with a deep tread to dispel underfoot water. When walking downhill the heel is required to provide most of the traction, and a heel brake is used in hiking boots to slow down the descent, and give maximum bite to limit slippage and sliding.
Pay attention to outsole design and construction when buying hiking boots, and make sure that the design matches the terrain you plan to cover and the conditions. High quality hiking boots use a well researched design to give the proper level of traction, and the highly technical construction will help to ensure that no matter what the terrain or gradient, you will be sure on your feet.