The theft happened around 4:30 a.m. Sunday behind the Irish Pub at 20th and Walnut, which was the starting point for the Tour de Shore ride.
According to investigators, a light-colored Ford pickup truck was driven up to the scene.
Then, the suspect or suspects got out and took the 15 bikes, valued at $22,000.
Anyone with information is asked to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.