75 Mile Bike

9 am start time

Snow, Gravel, Hills, and Thrills

This course is the real deal with 5000’+ of canyons, the Rowena trail, and plenty of adventure no matter what the weather.

NEW Route for 2025:

Similar to the 40 mile route, we’re adding in a loop around the frozen tundra that is the Boulder Reservoir in the winter. You’ll have an aid station at the “Res” at mile 19 to get topped off before you start climbing. You’ll then climb Lefthand Canyon up to the infamous Rowena trail. Snow is pretty much guaranteed on Rowena, so you are likely to get in some good off-the-bike action. Aid 2 awaits at Sunshine Saddle (mile 37.6) and this also marks the end of the 1st timed segment. Bundle up and enjoy an untimed cruise down Sunshine Canyon and through the City of Boulder. The 2nd timed section begins as you climb Linden. Use extreme caution through the twisty gravel downhills on Pinebrook and Wagonwheel Gap. You’ll still have 23 miles of mostly downhill mixed terrain riding ahead after you crest the final climb up Old Stage. Make sure to stop by the 3rd aid station (mile 68) for the final push back to Lyons. High fives await you at the finish line after this truly epic winter course. This is not for the inexperienced rider.

NOTE there is a time cut off at 12:30 pm at the entrance to Rowena. If you reach this point after 12:30pm, you must go back down Lefthand Canyon and continue with the course back to Lyons.


100K Course preview and tips video