Authorities received the call about the injured bicyclist at 10:09 a.m. Search and rescue teams headed to Glendora Mountain Road at mile marker 8.85 and quickly found the victim.
The man who is from Walnut and who was described as "an experienced mountain bike rider" said he had picked up too much speed on Glendora Mountain Road at Glendora Ridge Mountainway and could not prevent himself from going over the edge.
Injured, he used his cell phone in the remote area and "surprisingly" got a connection, said Capt. Mike Parker of the Sheriff's Headquarters Bureau.
Sheriff's Air-5 rescue helicopter and its flight crew found the man 35 minutes later and lowered two sheriff's paramedics via hoist while the pilots hovered over a deep ravine, Parker said.
Deputies Mark Desmarteau and Dan Aleman provided emergency medical attention for the injured man, secured him into a gurney and prepared to hoist him into the helicopter.
Desmarteau was hanging off the side of the gurney to protect and secure the injured man and was dragged through trees and brush, but the injured man was kept clear of the hazards.
After an "unnerving but necessary experience," the man was hoisted into the helicopter, Parker said.
In little more than an hour, the man was taken to a hospital where he was treated for non-life threatening injuries, which included back injuries and broken ribs.
City News Service contributed to this report.