Every entrepreneur wants a loyal fanbase, a group of repeat customers who will evangelize their favorite brand. But superfans come with challenges: They love a company exactly the way it is, and they do not want it to change. That was a problem for Tough Mudder, whose obstacle course races were attracting primarily young, fit men. To grow as a business, it would need to attract different kinds of people too -- but without alienating those core fans. On this episode, we explore how Tough Mudder did it.