Electronics retailing giant RadioShack will be the title sponsor of Levi Leipheimer's King Ridge GranFondo, the October cycling event expected to attract 6,000 riders.

"Other sponsors will be involved, but the presenting sponsorship takes on a hosting role, it is the significant level of sponsorship," said event organizer Greg Fisher of Bike Monkey.

RadioShack confirmed its sponsorship, but the details are still being worked out and an announcement is expected in a few weeks.

RadioShack is also the sponsor of Team Radioshack, which features Leipheimer, a Santa Rosa resident and premiere professional cyclist, Lance Armstrong and several other top riders from last year's Astana Cycling Team.

"That means everyone riding Levi's GranFondo will be part of Team RadioShack," Leipheimer wrote on Twitter, announcing the sponsorship.

Leipheimer is the driving force behind the GranFondo, held last year for the first time to help the city of Santa Rosa pay the costs of hosting a stage of the Amgen Tour of California.

Gran Fondo, which means "big ride," is a tradition in Italian cycling culture and just catching on in the United States. It is not a race, but a cycling event for the masses.

"The GranFondo format is new to the United States," Fisher said. "The audience for it has always existed, people have always clamored for it, but it has taken time to take hold."

The event will feature three rides of different lengths in western Sonoma County, with the longest and most challenging taking riders over King Ridge Road on the Sonoma Coast.

The GranFondo is 103 miles and the 3,000 spots have already been reserved, at cost of $130 per rider.

The MedioFondo is a 65-mile ride, of which the 2,000 spots have been sold, at $110.

The shortest ride, the PiccoloFondo, is 30 miles with a third of the 1,000 spots for riders sold, at an entry fee of $70.

"That was expected, for longer rides people plan farther out," Fisher said. "We fully expect them to be hot properties as we progress."

The Oct. 9 event starts at 8 a.m. at the Finley Center in Santa Rosa, where a festival will be held after the ride.

The inaugural event drew 3,500 riders and raised $100,000, of which $60,000 went to Santa Rosa. The city has to pay $175,000 to be part of the Amgen Tour of California.

The Forget Me Not Farm of Sonoma County, a non-profit that provides therapy for troubled children, is also a beneficiary from the GranFondo.

Fisher said it can cost as much as $250,000 to stage a GranFondo event.

He said they are also looking at sponsorship from Trek Bicycle Corp., Capo cycling apparel of San Francisco, Camelbak of Petaluma and Road ID.

RadioShack, based in Fort Worth, Texas, had 2008 sales of $193 million. The amount of its sponsorship was not released.

Leipheimer, who placed third at the 2007 Tour de France and is a three-time winner of the Amgen Tour, has indicated he will ride in the GranFondo.

Fisher said they hope to get other Team RadioShack riders as well.

Other top Team RadioShack riders include Jani Brojkovic, Chris Horner, Andreas Kloden, Jason McCartney and Yaroslav Popovych.