FOR ALL the excitement and high hopes around Portland's anticipated bike share system, it would be hard to find a city project that's more opaque.

In a recent round of calls to find out just how close the city is to its own shiny bike rental network—and whether we might expect further delays—responses were generally sunny and short.

A typical answer, from Portland Bureau of Transportation (PBOT) spokesman Dylan Rivera: "We really don't have much to add on bike share right now. When we finish ironing out the details with sponsors, it will be a very big deal and we will let you know."

But the hunt for those sponsors has been harder and longer than anyone imagined—a challenge also facing other cities seeking to install bike share systems. One expert says that difficulty might even reflect a new market reality, as other city's systems go live before Portland's. And if there's one thing that stands out in the various responses to the Mercury's inquiries, it's this: The supposed "spring 2014" launch date? Suddenly, no one's mentioning it.

Portland, it appears, may have to wait on bike share a bit longer.

Local firm Alta Bicycle Share, tapped by the city to implement a system in late 2012, has been casting about all year for roughly $6 million in sponsorship cash. That money would be used to purchase and set up a system with 75 stations and 750 bikes, and then operate it for five years. User rental fees won't be enough.

With no sponsors in sight, the city was already forced to bump back plans for a spring 2013 launch by an entire year ["Waiting for the Dough," News, March 20]. But if a deal isn't hammered out soon, even that generous extension won't be enough—officials say it takes six months to purchase and set up a system.

Alta President Mia Birk has said since March she's making progress on locating a sponsor, but to date none have been announced (though rumors about interest by health care giant Kaiser Permanente have swirled). And both Birk and Rivera notably cited only a "2014" launch in their emails—suggesting spring may be out of the picture.

"We are working hard and making good progress on the sponsorship!" Birk wrote. "Can't tell you much more yet... except that we are on course for a 2014 launch and really excited! Stay tuned."

Pressed if Portland might have to settle for another delay, she didn't respond. Meanwhile, new PBOT Director Leah Treat, who has first-hand experience getting Chicago's system running, declined a request for an interview.

If Portland is indeed facing delays, it's got company.

Seattle, a city shot through with corporate money, is struggling to find sponsors for the Puget Sound Bike Share (also being implemented by Alta). And Chicago's Divvy Bikes system, which opened this summer, has so far subsisted on public money alone. Same with the Bay Area.

"What you're experiencing is very typical," says Susan Shaheen of the University of California, Berkeley, who's studied bike share systems extensively. "Securing title sponsorship takes a lot of work, a lot of experience, and it's time consuming."

Or maybe Portland's just late to the party. As bike share pops up in city after city, Shaheen says, what once was a unique opportunity for rolling advertisements may lose its luster.

"Maybe part of this issue is: When these first title sponsors sign on, it's exciting and it's new," she says. "For the fourth and fifth installment, it's not as exciting.

"Maybe the first couple cracks at this was considered a better bang for your buck."