ZINN  FONDO GRAVEL, JUNE 21, 2025

We are super excited to host our first big ride from our new shop in Louisville, Colorado. Lennard has been hosting Gran Fondo’s from his house for ages, but after he developed his heart arrhythmia, riding over 200 miles in a day became a non-starter. Now that he’s been training on his gravel e-bike for years, he’s ready to bring back the Fondo, this time, a gravel version.

The Zinn Fondo* returns this year as a gravel ride on the summer solstice. This year it will start and finish at the Zinn Cycles shop in Louisville. Riders can choose one of three loops of approximately 60km, 85km, and 100km in length. There will be a ride leader for each loop. All three loops will be primarily on bike paths and dirt roads. The “Corto” (short loop) goes up Chapman Dr. and down Flagstaff Rd. The “Medio” (medium loop) goes up to Gold Hill via Fourmile Canyon Dr. and Gold Run Dr. and returns via Sunshine Canyon Dr. The “Lungo” (long loop) follows the Medio loop with the addition of turning left at Salina to continue along Fourmile Creek to Pennsylvania Gulch and up Switzerland Trail to Gold Hill Rd., rejoining the Medio loop at the Gold Hill Store. 

Zinn Fondo Gravel technical details:

Corso Corto (short loop): 59km, 2,300 feet of climbing (start/finish at Zinn Cycles shop)

OR, with alternative start/finish in Boulder at Eben G. Fine Park: 20km, 1,300 feet of climbing

Corso Medio (medium loop): 87km with 4,200 feet of climbing (start/finish at Zinn Cycles shop)

OR, with alternative start/finish in Boulder at Eben G. Fine Park: 37km, 3,200 feet of climbing

Corso Lungo (long course): 98km with 4,700 feet of climbing (start/finish at Zinn Cycles shop)

OR, with alternative start/finish in Boulder at Eben G. Fine Park: 48km, 3,700 feet of climbing

Climbing Switzerland Trail entails significant technical challenge on a road or gravel bike.

The descents of Sunshine Canyon and Flagstaff Mountain are not to be taken lightly—use appropriate caution. You and only you are responsible for your safety.

Start time is June 21 at 9AM at Zinn Cycles, 1655 Cannon Cir. Suite 100 in Louisville.

Alternative meeting/start time is approximately 10-10:15AM at Eben G. Fine Park bathrooms.

This is an unofficial ride with no entry fees and no feed stations. Riders are welcome to start and stop wherever and whenever they want and to join and leave the ride wherever and whenever they want. Some riders will stop for food at the Gold Hill Store. E-bikes welcome.

*The annual Zinn Fondo ride started in 1988 on Lennard Zinn’s 30th birthday. The idea was to ride hard all day in the mountains, enjoying great views with good friends. Many routes were used. The original and oft-recurring route was the 369km (229-mile) “Grand Loop” from Boulder with 19,000 feet of climbing over the Continental Divide: up to Estes Park, over Trail Ridge Rd., down to Granby and Winter Park, over Berthoud Pass, down to Idaho Springs, up to Nederland via Peak to Peak Highway, and back to Boulder. Distance and elevation gain are moderate now, as Lennard turns 67 this year and has a heart arrhythmia and an e-bike.