Outsole at a glance
- Typical life
- 300 to 500 miles on trail shoes
- Grip on rock
- Compound
- Grip in mud
- Lug pattern
Where the outsole sits in the stack
Three layers stack under your foot: the footbed you stand on, the midsole that cushions, and the outsole that meets the ground. Only the outsole is rubber, and almost everything sold as traction is a property of it.
What decides grip
Two variables do the work. The lug pattern decides how the sole interacts with soft ground and how well it sheds mud. The rubber compound decides how it behaves on hard ground, where grip is friction rather than penetration. Softer compounds like Vibram Megagrip hold better on wet rock and wear faster; harder compounds last longer and slide sooner.
What outsole wear tells you
Outsole wear is also diagnostic. Even wear across the forefoot is normal. Wear concentrated on the outer heel is a normal gait pattern. A sole that's smooth in the middle of the forefoot while the lugs around it are intact usually means the midsole underneath has packed out and stopped spreading load, which is a sign the shoe is done regardless of how the rubber looks.
What this means when you're choosing
- A named compound rather than unbranded rubber, since named compounds have published behavior
- Lug spacing wide enough to shed mud if you hike anywhere wet
- Whether the outsole wraps up at the toe into a rand
The common mistake
Judging a shoe by the tread that is left
A sole with intact lugs can be sitting on a midsole that packed out a hundred miles ago. Press the foam along the side: if it stays dented and shows deep creases, the shoe is finished regardless of how the rubber looks.
Common questions
How long does an outsole last?
On trail shoes, commonly 300 to 500 miles, though rocky ground and pavement shorten that considerably. Boots go much further, and on a resoleable boot the outsole outlives everything but the upper.
Can an outsole be replaced?
On a stitched or welted boot, yes, and a good cobbler will do it for a fraction of a new pair. On glued trail shoes and most modern hiking boots it isn't practical, because the midsole is bonded into the assembly.