Mammoth Tuff is a smaller, founder-driven race with an unusually long runway to its first edition. Dave Sheek and Amanda Nauman (a two-time Unbound 200 women's champion) started planning it in 2019, only for the inaugural running to be cancelled twice — once for COVID in 2020, then again in 2021 when wildfire evacuations and stretched emergency services in the area forced another postponement. The race finally debuted in 2022, and organizers and early reviewers alike have said it was worth the wait.
The name is a geology joke that doubles as a course description: 'tuff' is the term for consolidated volcanic rock, and the race is built around the Long Valley Caldera — an ancient supervolcano whose eruption roughly 760,000 years ago left behind the Volcanic Tableland the longer courses cross, along with the geothermal activity that still feeds the hot springs along the route. Mammoth Tuff runs the week after the (road) Mammoth Gran Fondo, which makes the Eastern Sierra a viable full-week cycling trip for visiting riders willing to do both. Besides, it's the only race (according to our records anyway) that has a beer mile.
Mammoth Tuff is also a UCI Gravel World Series qualifier — the longest distance qualifies all younger age categories, and the middle distance qualifies riders 50 and over, with the shortest distance not counting toward Worlds qualification at all.
The short course circles the caldera itself; the medium and long courses continue out across the Volcanic Tableland, through a genuinely varied high-desert landscape most California gravel races don't touch.
Registration runs through BikeReg and the event’s own site (tuff.ventures/mtuff); registration opens in February and is available on a first come first served basis.