Unbound Gravel, formerly called “Dirty Kanza” or “DK”, has exploded in recent years to become the biggest bicycle race in the United States, and the biggest gravel bike race in the world.After reading and hearing about it for years, I signed up to race the 100 mile version and made the trek to Emporia, Kansas, aka “Gravel City USA” last weekend to put on a race number and test my legs on the Flint Hills gravel.  Here’s everything the aspiring racer should know!