Looking for an Alternative to the now delayed "bikeshare"? Josh Brustein has you covered!

But City Hall has no monopoly on the concept of sharing bicycles, and two start-ups are working on alternatives to Citi Bike and its planned 10,000 bikes, specially designed bike racks and smartphone app to let riders navigate the system.

The shoestring start-up Spinlister is a Web site (and in the coming months, a mobile app) that operates on the same principle as other sharing-economy companies like Airbnb or Taskrabbit. It has been connecting people with underused bicycles to cyclists without wheels for several months already. If what you are looking for is a bicycle for the day, it can be much cheaper than the available alternatives, while giving you that warm, fuzzy feeling of being in on something.

Spinlister is a small-time operation, with the company’s founder, Will Dennis, 23, at its center. About 80 bikes are currently listed in New York City (it also operates in San Francisco), and Mr. Dennis says the site has facilitated hundreds of rentals in recent months. At least 20 of those are of Mr. Dennis’s own six-gear bicycle, the Blue Lady Killer. (Other Spinlister users offer bikes with names likethe Red Devil, Midnight Rider and Maggie.)

Mr. Dennis argues that Spinlister can coexist with the city’s program because it serves a different market. The pricing for Citi Bike is set up for people intending to ride for no more than an hour or two; after that, the fees pile up quickly. Spinlister’s rates, by contrast, are based on daylong rentals. Plan on spending about $20 to rent a bike for a day, although some people ask much more for high-end road bikes.

Unlike Citi Bike, Spinlister does not reward spontaneity. Getting a bike depends on arranging a meeting with its owner, and most of these people are presumably not just sitting around waiting for your e-mail. I tried twice to rent a bike on less than a day’s notice and failed both times.

But the big question is how the service, as it grows, will deal with theft and fraud. Spinlister deems the renter responsible for damaged or stolen bikes, but it is unclear how it can enforce this policy. To reassure people who list bikes, the service guarantees to cover losses of up to $5,000. Mr. Dennis says it has not had to pay out yet, quite likely because Spinlister remains so small. It is hard to see this good luck lasting forever.

Social Bicycles is working on a bike-sharing program that seems more in line with the city’s idea. (Indeed, the three-man company bid for the contract to run the city’s program but was beaten out by Alta Bicycle Share.)

The twist with Social Bicycles is that instead of custom-built racks that people visit to pick up shared bikes, the bikes themselves come with built-in locks and GPS units. When people want bikes, they can look at a smartphone app to locate one, then unlock it by entering a PIN into a small computer on the back of the bicycle. When they’re done, users simply lock up the bikes at their final destination and walk off.

In addition to being convenient, Social Bicycles argues, this method is relatively inexpensive: The cost per bicycle is about 25 percent of what it will be under the city’s system.

Social Bicycles is still early in its development. The company is working with clients like the city of Buffalo and San Francisco International Airport, which is establishing a bike-sharing program for employees who need to get between terminals. Some of these programs are expected to be running in the coming months.

The company has aspirations to supplement New York City’s bike-sharing program as it expands geographically. For the moment, the only place you are likely to see one of the bikes around here is outside the offices of BMW’s start-up incubator in the West Village, where the company is based.

Have a favorite New York City app? Send tips via e-mail to appcity@nytimes.com or via Twitter to @joshuabrustein.