In December, the three municipalities agreed to create a combined system. Bike and Roll, a rental company, was to operate it, in partnership with e3think, a planning group, and P3GM, a management and marketing firm, as well as the German manufacturer Next Bike, which has 20,000 bikes being shared in 14 countries (the northern New Jersey system was to be its first in North America).

But bad publicity generated by technological and financial problems at Alta Bike Share, Citi Bike’s corporate parent, made potential sponsors of the New Jersey network wary.

The lack of sponsors, in turn, delayed the start of the program, though Tom Glendening, the president of e3think, said the partnership was not contractually obligated to have the system up and running until October.

Mr. Fulop, meanwhile, began to rethink the bicycle needs of his city of 254,000. He decided that Jersey City residents would be better served by the system already in place in New York.“What’s most important for me is that folks in the Heights or Greenville,” two of the city’s neighborhoods “where there’s not great access to the PATH, can get to the train, get out on the other side and then get on a bike,” he said.

The mayor said he also viewed joining the Citi Bike system as a way of attracting New Yorkers to jobs, restaurants and cultural offerings in Jersey City. “With Citi Bike,” he said, “the benefits go both ways.”

Weehawken, which has 13,500 residents, decided to stick with Hoboken.

“We’re neighbors, so it’s a great way for people to go out to restaurants or shops in either place, as well as an alternative means to get to the ferry,” Mayor Richard F. Turner said.

“The terrain is pretty tight, very up-and-down around here,” he added, “so we’ll see how popular it is.”