Last updated January 12, 2025

A truly famous or infamous (depending on the person) race, the Grizzly 100 & Big Bear MTB Gran Fondo is a Saturday spectacular of multiple mountain bike race lengths held in the gorgeous area of Big Bear Lake, California. Once two separate mountain bike events, the Grizzly 100 and the MTB Grand Fondo, are now joined into one day of non-stop pedalling. The Big Bear MTB Grand Fondo and The Grizzly 100/75 is one of California's top mountain bike events and one of the top MTB occasions in the United States. Strambecco could not recommend this event more, and it consistently makes our list of Best Mountain Bike Events in the Southwest.  Of special note, the Grizzly 100 race is part of the National Ultra Endurance (NUE) Series.

One previous participant shared, “Derek and Bear Valley Bikes made this event one of the best events I have ever been on with the Mountain Bike. Seriously exceeded my expectations.”

What sets this event apart is not just its location but also its pull. Drawing elite mountain bikers from every corner of the globe, it offers an unmatched experience. The Grizzly 100 & Big Bear MTB Gran Fondo is internationally acclaimed. Its intricate blend of challenging single-track, double-track, and fire road climbs and descents attracts mountain biking enthusiasts. The towering altitudes, ranging between 7,000 to 8,500 feet, add to the adrenaline rush.

Event & Course Info

Delving into the route and terrain, the Grizzly 100 & Big Bear MTB Gran Fondo offers a multitude of routes to cater to every type of rider, from the rookie to the seasoned expert. For the daring riders opting for the 75k and 100k courses, they will first tackle the 2N08 climb and then embark on 2 (for 75k) or 3 (for 100k) laps of the 50k upper loop, covering Helipad, Lodge Pole, and Cabin 89/Pine Knot. The MTB Gran Fondo segments - 30k & 50k Skyview - are ideal for those looking to enjoy the scenic beauty of Big Bear with sports climbs.

Starting with the route MTB Gran Fondo, which can be categorized as spot climbs with multiple categories, allowing almost every level of rider to enjoy the event and race. The Fondo has 30k and 50k options. The 100k fondo is a 'rider to recovery' event aiding veterans' recovery, an extraordinary addition to Saturday. Then there is the beast of the Grizzly 100k and 75k. The Grizzly has gained international recognition as a spectacular and physically demanding endurance mountain bike race that spans some of California's best single track and double track, climbing thousands of meters while all taking place at a hypoxic altitude of up to 8,500 feet!

While the physical demands of the routes are undeniable, participants will find solace and rejuvenation at the various aid stations spread across the course. These stations will be stocked with Hammer Nutrition, Bob's Pickle Pops, water, and other specialty items catering to the needs and cravings of the riders (think banana & Nutella sandwich with M&Ms, pickle spears, PB-filled celery sticks, Grandma Betty’s Homemade Cookies, bacon, watermelon)

The Grizzly 100 and 75 is the final race of the National Ultra Endurance Race Series (NUE) this year, making it a physically challenging venue to end on and sure to bring some heavy-hitting riders. There are eight categories in the Grizzly 100/75 that all attribute points to the NUE series. For the 100k and 75k routes, there are single speed categories and a masters (50+) age grouping for men and women. Beyond that, both 100k and 75k routes have a men's and women's open category. The Grizzly course is no joke, and the dreaded Radford Climb has been voted as "one of the most dreaded 5-mile climbs in California." NUE Top-of-the-line aid stations are more than just fully stocked; they have great local fans and amazing participants and volunteers.

Area Accommodations & Things to Do

There is no official lodging partner for the Grizzly 100 & Big Bear MTB Gran Fondo. Still, there are many options for hotels nearby, including Big Bear Cool Cabins, Holiday Inn Resort, The Lodge at Big Bear Lake, or Robinhood Resort. Campgrounds include Pineknot and Serrano in the San Bernardino National Forest. Several family-friendly restaurants offer indoor and outdoor seating right on Big Bear Lake, such as Peppercorn Grille, Teddy Bear Restaurant, and Santana & Mavericks Bar & Grill.

Big Bear Lake, voted Expedia’s #1 rated weekend getaway city and Southern California’s most scenic and popular riding destination, is often regarded as the cycling capital of the region. Its reputation is well-earned, having played host to prestigious cycling events like the AMGEN Tour of California and the Redlands Bicycle Classic. With its picturesque vistas, well-maintained roads, and ample cycling opportunities, it’s no wonder that Big Bear Lake has earned the hearts of cyclists from far and wide.

It should be no surprise that Big Bear is a mecca for mountain biking, with a vast network of trails catering to riders of all skill levels. The Snow Summit Bike Park, accessible by chairlift, offers exhilarating downhill trails and features like jumps and berms for adrenaline-pumping rides. For cross-country enthusiasts, the Skyline Trail provides stunning views of the San Bernardino Mountains and Big Bear Lake. Those seeking more technical challenges can explore the Santa Ana River Trail or the famous “Radford Climb.”

Big Bear’s scenic trails also cater to trail runners. The Pine Knot Trail, starting from the Aspen Glen Picnic Area, is a favorite among trail runners, offering a moderate ascent and rewarding views of Big Bear Lake. The Cougar Crest Trail, located near the Discovery Center, offers a challenging run with panoramic vistas of the surrounding mountains.

With its crystal-clear waters and stunning alpine backdrop, Big Bear Lake also provides an ideal setting for stand-up paddleboarding. Athletes can rent paddleboards from several shops around the lake and spend a relaxing day gliding on the water.

About the National Ultra Endurance (NUE) Series

The National Ultra Endurance (NUE) MTB Series is one of the premier mountain biking race series in North America, dedicated to ultra-distance mountain biking enthusiasts. The series is composed of Epic Series events, which are grueling 100-mile races, and Marathon Series events, which are 50-mile to 100k length races.  Each race/event challenges riders' endurance, technical skills, and determination on some of the country's most scenic and rugged courses.  The NUE Series was established in the early 2000s to provide a competitive long-distance mountain biking platform. Its goal was to elevate ultra-endurance mountain bike racing and build a community of athletes passionate about pushing their limits. Over the years, it has expanded to include multiple events spanning diverse terrains across the US and several global locations.  In 2025, the Series final takes place at the Oak Ass 100/50 in Alabama.

Participation in individual NUE events is open to all riders, but registration fills quickly due to the series' popularity. Riders must complete at least three events to qualify for overall series rankings, with points awarded based on finishing positions and the best four results counting toward their total score. Categories include Open Men, Open Women, Master 50+ Men, Master 50+ Women, and Singlespeed, with all participants required to meet strict time cutoffs to be considered finishers. The series offers significant rewards, including cash prizes, custom jerseys, trophies, and recognition for top finishers, while providing a platform for riders to gain exposure, attract sponsorships, and join the ranks of endurance mountain biking legends.

The National Ultra Endurance MTB Series is not just about racing—it's a celebration of mountain biking culture, showcasing breathtaking courses, fostering community, and pushing the boundaries of what riders can achieve. Whether you're a seasoned pro or an aspiring ultra-endurance athlete, the NUE Series offers an unforgettable experience.  You can see the full roster of NUE events Strambecco's Series Page here with full reviews.

Related Events

For multi-sport athletes looking for events to round out their calendar that are located in the area, be sure to check out Tour de Big Bear from Big Bear Cycling Association, which is one of the best road cycling events in the Southwest and California - it is also affiliated with the Mammoth Gran Fondo as both events make up the California Pass Challenge for riders that conquer both iconic rides. But be sure to also check out our full list of Strambecco Best in Class trail running and gravel cycling events.

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