Kim Flint's GPS after going 49.3 mph down South Park.

The cyclist who was killed going down South Park Drive in Tilden Park on Saturday June 19 may have been racing down the hill to regain a speed record that he had only held for a week.

William Flint II, who called himself Kim, had raced down the same hill on June 6 in 2 minutes and 7 seconds, reaching a top speed of 49.3 miles per hour, according to his Twitter posts.

“49.3 mph, on a bike. How I find religion on Sunday morning,” wrote Flint on June 6.

“Set new personal records – Centennial, 3 Bears, some others. even a KOM (King of the Mountain) on south gate descent!” he added a few hours later.

But on Tuesday June 15, another bicyclist, Pan Thomakas, bested Kim’s record by 4 seconds. That new time may have prompted Kim to try and go even faster, according to comments on bicycle chat rooms.

Flint and Thomakas are part of a subset of bicyclists who use GPS devices to track their routes and speed and then share the results on a social networking site called

South Park Drive in Tilden Park in Berkeley is well known in the bicycling community for its steep descent. The road from Grizzly Peak toward Wildcat Canyon Road is a 15% grade. Bicyclists can reach speeds of 50 miles per hour, according to Mark Sapiro, president of Grizzly Peak Cyclists, a 40-year old bicycling club with 570 members.  The posted speed limit is 30 miles per hour.

One bicyclist described the road this way: “South Park is the fastest descent in the East Bay; the top part has curves but isn’t twisty enough to slow you down, and then you can blast out of the last turn into the steepest part of the descent, a straightaway near a parking lot. I hit 88.5kph once (my fastest recorded speed anywhere).”

The hills of the East Bay are filled with bicyclists on the weekend, and some just want to see how fast they can go, said Sapiro.

“It’s one of the few roads in the Bay Area, especially the inner Bay Area, where you can exceed 50 miles per hour on a bicycle, so there is a certain element that wants to see how fast they can go,” said Sapiro. “I will admit I went more than 50 mph on South Park and it was really stupid and I won’t do it again.”

While the road is not too curvy, it’s dangerous, said Sapiro. There are families and pets hanging out in picnic spots along the road. They can wander into a bicyclist’s path unexpectedly. In addition, cars pull in and out of those spots.

“There are too many possibilities that something unforeseen can get in your way,” said Sapiro.

Sapiro said that bicycle chat rooms were buzzing with the news of Flint’s death, especially since he seemed to be trying to regain a speed record he had recently lost.

Flint, 40, of Oakland, was killed around 2 pm on June 19 when he broadsided an SUV, according to Lt. Dave Dubowy of the East Bay Regional Park District police. Flint was going downhill, in a northbound direction, when his bike traveled into the southbound lane and hit the left side of the car, said Dubowy. Flint had been going around a curve when his bike crossed over.

Skid marks at the scene show that Flint applied his brakes. He was wearing a helmet. He was airlifted to John Muir Hospital in Walnut Creek, where he was pronounced dead.

Flint who was born in Berkeley but who grew up Danville, got a joint engineering and computer science degree from UC Berkeley. He worked at NVIDIA, a visual computing company based in Santa Clara, and had assisted Sony in the development of the PlayStation. Flint lived in Oakland with his girlfriend.

Flint was an avid cyclist, going out on long rides almost every weekend, according to his Strava account. He frequently rode in Tilden Park, and had done a long loop in Niles Canyon in Fremont the week before his death. His friends say he was not a reckless person.

“I’ve known Kim for 8 years, and he is one of the brightest and most responsible people I’ve had the pleasure to call my friend,” wrote donthebartender a friend, in the comments section of the SFGate website. “I’d like to let any readers know that he wasn’t a reckless individual. He was a consistent regular rider who knew the local roads well and was far too smart to take perilous risks intentionally. We can’t know what happened in that moment, except that what happened was a tragic accident that many people will feel the pain of for years to come.”

Flint also owned a Porsche 912 that his father had purchased just days before his birth in 1969. His father sold the car, but bought it back years later. Flint documents the car in an touching slide show with commentary on his website.

Friends will be celebrating Kim’s life Friday June 25 at 7 pm at Heinhold’s First and Last Saloon in Oakland’s Jack London Square. It is not a formal memorial, but a gathering of friends.

Photo from Kim Flint’s Twitpic account

Frances Dinkelspiel, Berkeleyside and CItyside co-founder, is a journalist and author. Her first book, Towers of Gold: How One Jewish Immigrant Named Isaias Hellman Created California, published in November...