One of Boulder’s ‘secret training grounds’.
Length: 3.0 miles (4.82km)
Average Grade: 7.3%
Maximum Grade: 12.3%
Vertical Gain: 1163 ft (354m)
Summit: 8088 ft (2056m)
Tour de France Category: 2
Tour de France analogue:
Col de Portet-d’Aspet – Second Climb, Stage 15, 2010 TdF.
This ride starts right from the edge of town and is only a 15 minute ride from the furthest point in Boulder. Unless you’re prepared to descend steep dirt roads, it is a dead end street, but can be extended with various lollipop loops. The profile on this page is measured from Wonderland Drive to the high point on Lower Timber Lane (the left fork at the end of Linden Drive).
The ride is known as a secret training ground because of it’s very low bike traffic, and access to many difficult dirt roads which are frequented by ‘crossers as the fall nears. The climb is more punchy than the profile above indicates. There is 1/10th mile at the bottom which tops 12% and really puts a sting in the legs to get the ride going. If you loop left on Timber Ln, expect rollers followed by a steep finish. Turning right is steeper initially, a brief downhill, followed by an easier grade to the highpoint.
Another common variation is to make your first left after 1/2 mile at S. Cedar Brook Drive and continue the 1/2 mile to the upper Mt. Sanitas trailhead. This will put a quick hurt on you with exactly one mile averaging a steady 8%.


