The 2014 Amgen Tour of California is going to spend only one day in the Bay Area, but it could be the toughest in race history with two mountain climbs.

Tour organizers unveiled the routes of the eight stages of the Tour of California on Thursday, and Stage 3 on May 13 from San Jose to the summit of 3,864-foot Mount Diablo -- with a climb up Mount Hamilton on the way -- could be a defining day in the race.

Stage 3 begins at Lake Cunningham Regional Park on the east side of San Jose and after five miles heads up Mount Hamilton. The route to the summit is different from the one used in past races. There are 22 switchbacks on the long, steep climb. The descent will be steep and technical along San Antonio Valley Road and Mines Road.

Stage 3 of the Amgen Tour of California heads up the south side of Mt. Diablo east of  Danville, Calif., Tuesday,  May 15, 2012.  (Karl Mondon/Staff)
Stage 3 of the Amgen Tour of California heads up the south side of Mt. Diablo east of Danville, Calif., Tuesday, May 15, 2012. (Karl Mondon/Staff)

The riders will pass the east side of Livermore before the route picks up where it did last year from Danville to Mount Hamilton. Riders will gain 3,300 feet of elevation on an average 6 percent grade on the 10.8-mile climb.

This will be the lone Bay Area stage for the tour. Livermore, which was the start of the Mount Diablo stage last year, declined to participate this year. Mount Diablo is making its third consecutive appearance in the tour. San Jose is the only city to be a part of all nine Tour of California races.

The event begins with Stage 1, which starts and finishes in Sacramento on May 11. Stage 2 is a time trial in Folsom.

After the San Jose-Mount Diablo trek, Stage 4 will go from Monterey to Cambria, down Highway 1 through Big Sur.

After running a south-to-north course in 2013, the tour will once again begin in Northern California and finish in Southern California, culminating with Stage 8 from Pasadena to Thousand Oaks on May 18.