After Jack Backus, an Oakland cyclist, sped down a hill in Joaquin Miller Park recently, he raced home to upload information about the ride to a Web site called Strava.

Once Mr. Backus’s GPS had sent statistics to the site, he could see his average speed and compare his performance to others on the same stretch.

Mr. Backus, an architect, is one of scores of bicyclists in the Bay Area who are flocking to Strava, a virtual cycling club started in April 2009. It lets members record their rides, create routes using computerized maps and ride in virtual competitions.

“It’s kind of an interesting way to connect with other cyclists and to have a little bit of a competitive thing going,” Mr. Backus said.