Free Air for Everyone! (On Bicycles.)

As trains rattle overhead, bikers whiz by a large phosphorescent green pump bolted to a sidewalk in Brooklyn under the Manhattan Bridge. Some notice and some don't, but almost no one stops.

But for Biko Weeks, 26, the city's new pilot project — a pair of pumps here and under the Williamsburg Bridge — is heaven-sent.

"Thank God they got this," said Weeks, whose tires were starting to sag.

They're not as dramatic as bicycle lanes or CitiBike, the cycle-sharing network, but Department of Transportation officials thought free air pumps could be a nice amenity that could help make urban biking just a little bit easier.

"Pumps are widely available, but not everyone can afford to buy their own; gas stations are often not located on bike-friendly streets; and bike shops are not always open," the department's press office said in an emailed statement. "These pumps are a low-cost, highly visible way for the city to improve upon the existing bike infrastructure already installed and improve the overall cycling experience for New Yorkers."  

Weeks often has a pump with him, but not today. He was concerned about wiping out. 

"If your front tire or your back tire is a little low, and you make a turn, it can just slip right out from underneath you," said Weeks, a bike courier, Uber driver and engineering student.

The pumps cost $450 each. Another one is coming soon to the Ferry Terminal on Staten Island.

The city will see how well they hold up to use by cyclists — and to the outdoor elements. If they pan out, the spokesman says, the city could install several in each borough. But there's currently no timeline for expanding the program.