What is the Grunt and Gnarl factor?

Every trail in our directory has a grunt and gnarl factor calculated, to give you an indication of how demanding and technical the route is.

Rob Bathgate

Written by Rob Bathgate

Updated August 25, 2023

The Grunt Factor is a measure of how demanding a run is. It takes account of the distance, the nature of the terrain, and the nature of the trail. The higher the number the more demanding it is. 75+ is considered Extreme.

The Gnarl Factor is a measure of how 'gnarly' (technical) a run is. It takes into account the nature of the trail and how steep it is. Lower scores indicate non-challenging running while higher numbers indicate technically difficult running. Bear in mind that it is an average for the whole run - there will always be harder and easier sections.

You'll find these on the specs of every trail in our directory.

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