By now, you may have heard that Robin Williams was a cycling fanatic. He loved the sport—its history, its pageantry, its champions magnificent and raffish.

He was also a devoted rider, and adored the machinery. Over the years, Williams accumulated a substantial bicycle collection—what Jay Leno does with cars, Williams did with bikes.

"He had everything," said Chad Nordwall, owner of Above Category, a high-end bicycle retailer based in Marin County, Calif., where Williams was a devoted client. "Everything."

Williams collected bikes of all types, but he was passionate about one brand in particular: Pegoretti. If you know bicycles, you probably know Pegorettis. Custom-made in Italy by master builder Dario Pegoretti, who built frames for cycling icons such as Miguel Indurain, they are wild pieces of art, almost always steel, colorfully painted by hand. They're also serious road machines. Imagine riding a high-performance Basquiat. That's a Pegoretti.