Robin Williams wasn't only one of the wackiest people on the planet. He was also an avid cyclist and advocate for differently-abled people.

Now, more than two years after his suicide, 87 bikes in his assemblage are up for auction, and the proceeds will help fund two charities he cared about deeply.

The Challenged Athletes Groundwork gives grants and support to athletes with infirmities, and the Christopher and Dana Reeve Foundation funds research and helping to aid people with spinal cord miseries.

"Though bright, skin-tight spandex still remains one of the more embarrassing outfits to regularly witness your Dad wearing growing up, the sport of biking and the people Dad helped through his love of it will always hold a special place in the hearts of our family," the Williams family said in a statement.

The family added to would-be buyers: "And though not required, may we suggest wearing the loudest, most vibrant and brightly-patterned, skintight biking gear possible when riding them? Keep the tradition alive."

The collection is on Paddle8.com, and the online auction will run until October 25 at 1 p.m. ET. It contains a number of luxury racing bikes

A polka-dotted "Master Pisa" Futura 2000 bicycle, made by Colnago and La Carrera, is among the most precious. It has already gotten a $19,000 bid.

"We hope these bikes will bring their new owners as much joy as riding them, and helping these causes, always brought him."

Williams was no casual cycling fan; he accompanied the Tour de France and biked in many events of his own. As such, the lot includes rare team issues and custom-made bikes. And, for burlesque of course, there's a unicycle.

The auction runs through Oct. 25 and comes with a very sweet intimation politeness of the Williams children:

"Though not required, may we suggest wearing the loudest, most vibrant and brightly-patterned, skintight biking gear possible when riding them?" they said in a statement. "Keep the tradition alive."