The number of trucks, still the workhorses of the distribution plan, will increase, too: A spokesman for the Transportation Department said that three large box trucks would be added by the end of the month, bringing the total to six. (The number of smaller trucks will be reduced to five, from eight.) There are now 50 people charged with balancing bikes; there were 15 when the program began.

Given the program’s history of software trouble, an unbalanced bike stock, as the Bloomberg administration takes care to point out, is not the worst problem to have.

“The challenges are related to the success of the system itself,” Janette Sadik-Khan, the city’s transportation commissioner, said. “The numbers are so big you really have to take a ‘Star Trek’ transporter just to keep up with the demand.”

Less than three months after the program was introduced, more than 70,000 people have become annual members. Between those cyclists and others who buy temporary passes, riders have taken more than 40,000 trips on some of the system’s busiest days — about seven for each bike in circulation.

But distribution challenges have unquestionably curbed the system’s ridership, leaving some commuters with a daily uncertainty: Will a bike be waiting?

“That’s my biggest anxiety every morning,” said Anthony Mauceri, 50, a Long Island Rail Road commuter, standing beside a subway entrance on West 33rd Street last week. “I come out of here and look.”

On the program’s Facebook page, where riders still bemoan customer service response time and unreliable updates on the system’s app for station information, members frequently appeal for more bikes in their neighborhoods.