Thousands of bicyclists will flood the roads of Santa Rosa and west Sonoma County on Saturday as part of Levi Leipheimer's GranFondo.

Cyclists come from six continents to participate in the mass ride, which takes in some of the county's most scenic and challenging roads and raises money for a host of charities.

Now in its fifth year, the Fondo appears largely undiminished by the admission of its namesake — Santa Rosa-based Leipheimer — that he took performance enhancing drugs during his pro cycling career.

Organizers say the 7,500 spots in the ride sold out this year at about the same rate as they did before Leipheimer confessed to doping in late 2012.

"People value the GranFondo for what it is," said Greg Fisher, spokesman for Bike Monkey, the event organizer. He said it is a day that encompasses "the spirit of cycling and what it means to be on a bike."

The event is anticipated to raise about the same for charity as last year — $250,000 — including donations to schools and fire departments along the three routes of varying difficulty.

The toughest and most popular, a 102-mile ride from Santa Rosa and back, includes King's Ridge northwest of Cazadero and involves more than 9,500 feet of climbing.

Shaun Ralston of Santa Rosa, who will be riding it for the fifth time Saturday, said "there's something magical about the Fondo — an unexplainable, almost intimate camaraderie of starting this hometown ride with thousands of like-minded cyclists at every skill level."

The event is timed, but is not a race. Beside raising money for nonprofits, organizers estimate the Fondo generates more than $3 million in economic activity by way of more than 1,000 hotel rooms that get booked, as well as restaurant meals and other revenue.

The Sonoma County Bicycle Coalition, which helps enlist volunteers for bicycle valet parking at the festival after the ride, reported that at least two former volunteers said they would not participate this year because of Leipheimer.

"They said they don't want to support Levi anymore because of the whole doping thing," said Aileen Carroll, the coalition's outreach director.

"I would hope this event is bigger than that — it's a Sonoma County thing, a community thing and it's not specifically linked to Levi's celebrity, and it can continue after such an upsetting thing," she said.

Carroll said they are short volunteers for valet bike parking, but that's because more are needed this year. The reason, she said, is that the bike parking is farther away, due to construction at the Finley Center on West College Avenue where the Fondo begins and ends.

Fisher said there has been no dropoff in the amount of volunteers who do everything from handing out registration packets to manning rest stops, driving support vehicles, and acting as course marshalls to ensure cyclists are following the rules of the road.

He said the event requires 1,000 volunteers and "we got 'em. Our shifts are full."

The GranFondo "is largely untarnished," said Stephen Lockert, an organizer who handles thousands of emails from participants.

He said that may be in part because Leipheimer came out earlier and admitted his involvement in the systematic doping that defined pro cycling for many years. That was in contrast to the vehement denials of seven-time Tour de France winner Lance Armstrong, who eventually acknowledged cheating.

Lockert said the bigger issue for the Fondo is trying to soften the blow of so many cyclists on the road in such a short amount of time. Some residents along the road can feel trapped for a few hours.

But organizers have done their best to alert west county residents to the inconvenience with road signs, 5,000 mailers and newspaper ads announcing road closures when the bulk of riders pass through.

(You can reach Staff Writer Clark Mason at 521-5214 or clark.mason@pressdemocrat.com.)