By Clark Mason

We all know professional bike riders are fast.

Levi Leipheimer of Santa Rosa prepares to talk to more than 7,500 bicycle riders at the start of his King Ridge GranFondo, Saturday Oct. 1, 2011 at Finley Park in Santa Rosa. (Kent Porter / Press Democrat)

If there was ever any doubt, Levi Leipheimer came up with a couple impressive numbers this week in his talk at a Healdsburg Chamber of Commerce luncheon meeting.

“What is the top speed you’ve gone downhill?” asked a cycling enthusiast.

“I know the Tour of Switzerland this year, or last year, kilometers was about 115 (per hour), so about 75 miles an hour,” Leipheimer replied.

“It’s not really fun at that speed,” he explained, provoking some nervous laughs from his audience. “You can’t wait for it to be over.”

Even more amazing were the circumstances in which he clocked it.

“This year, we did that in the rain, through a tunnel as well.  Not fun,” he said. “But it’s part of it.”

We checked Levi’s math, and assuming he was going 115 kilometers per hour, that translates to 71.5 miles an hour, a little less than what he claimed. But we’ll give him the benefit of the doubt.

It’s still crazy fast. And it was enough for him to win the Tour of Switzerland this year — even if just by four seconds overall.

Now for that second amazing Levi statistic, only a little closer to home.

Leipheimer thrives on Sonoma County’s backroads, making it abundantly clear the terrain and climate make for a perfect training ground.

“Sonoma County has made me a better cyclist,” he said. “I love these roads.”

Pine Flat, one of the favorite climbs for cyclists to challenge themselves on, has a heart-pounding ascent of more than 3000 feet in elevation over more than 11 miles.

Only a handful of top riders ever make it in less than an hour to the top during organized time trials.

Asked his best time, on Pine Flat, Leipheimer said “I believe I’ve done it in 46 (minutes).”

Then he added, “Twice in one day though.”

That provoked more amazement and laughs.

“I wasn’t trying to be funny,” he said.