Last Updated June 8, 2024 In the Flint Hills and Kansas Prairie, Unbound Gravel 2025 is the granddaddy of Gravel events and a true bucket list event for gravel aficionados.  Formerly known as Dirty Kanza, the popularity of Unbound Gravel continues to grow from 34 participants in 2006 to well over 4,000 riders annually. The…