The First Bike Trip up Lookout Mountain
The exact date for the first bike trip up Lookout Mountain in unknown.

Upper Hairpins, 1890-1910.
The wagon road at the Upper Hairpins as it appeared to cyclists. There was only one hairpin. The spur leading towards the bottom of the image leads to Lariat Spring. Barely visible down in the valley at lower right is part of the wagon trail.
Courtesy: The Denver Public Library. Western History Collection. [Z-3599].

The newly paved Lariat Road appears black on Lookout Mountain, 1931-1935.
Courtesy: The Denver Public Library, Western History Collection. [X-24004].
The earliest written documentation for a cyclist riding up Lookout Mountain is 1893.
However, three Denver cyclists (Horace Greeley Kennedy, a trick cyclist; a Mr. Perkins; and another cyclist) rode up Pikes Peak on June 28, 1891. They were probably riding chain-drive safeties with no freewheel and a 64-to-70 inch gear. They had almost certainly ridden up Lookout Mountain by this date. Cyclists visiting Denver from the east were regularly entertained with a ride up Lookout Mountain during this period. It is very likely that the first bicycle ascent of Lookout Mountain occurred prior to 1891. At this time, cyclists rode up the wagon road in Chimney Gulch. Chimney Gulch is the location of the popular hiking and mountain biking trail up Lookout Mountain today. Near Windy Saddle, and again further up the present road, remnants of the old wagon road remain visible.
Steve Stevens of Golden Oldy Cyclery kindly provided this historical information.
First Bike Accident in Colorado
Although the first bike accident in Colorado didn’t occur on Lookout Mountain, it happened in nearby Golden.
In 1869, Jim Boyd was descending the steep hill on Ford Street heading towards Clear Creek. He was riding a velocipede with steel rims and steel brakes. The steel-against-steel brakes were inadequate for the task of stopping and Jim crashed into Clear Creek.
This story was kindly provided by Steve Stevens of Golden Oldy Cyclery.

View east from Double (Lower) Hairpins towards Golden, 1913-1920.
The new, gravel road is a big improvement over the old wagon trail.
Courtesy: The Denver Public Library, Western History Collection. [MCC-2068].