A 55-year-old cyclist died Saturday morning after he lost control of his bike while riding down Mount Lemmon.

He was traveling "southbound on the highway at a high rate of speed and failed to negotiate a curve in the road," said Deputy Jesus Bañuelos, spokesman for the Pima County Sheriff's Department. The bicyclist "left the roadway and struck the side of a hill, causing a fatal injury."

The rider, whose name has not been released, was riding down the Catalina Highway just past Rose Canyon. He was pronounced dead at the scene.

The crash did not appear to be caused by equipment failure, Bañuelos said.

Thumbtacks in the road do not appear to have contributed to the crash.

Local cyclists recently have reported several incidents of tacks deliberately dumped in high-traffic areas for bicyclists.

Pima County sheriff's deputies are investigating at least one incident in which hundreds of tacks were strewn along a portion of the Catalina Highway frequented by cyclists.