PORTLAND — Portland residents have ridden 136,000 miles on bike-share program bikes since the program launched in July. Since July 19, Biketown users have taken nearly 59,000 trips, making progress toward the city’s goal of having 400,000 rides in the program’s first year, The Oregonian/OregonLive reported. Biketown General Manager Dorothy Mitchell said the shared bicycles are getting so much more use than expected that mechanics had to be called for tuneups sooner than expected.