Ride-hail giant Lyft has exclusive rights to operate a bike-rental program on San Francisco streets, whether its two-wheelers are parked in docks or tethered to random bike racks, a San Francisco judge said Tuesday.

The tentative ruling showed that Superior Court Judge Ethan Schulman is inclined to side with Lyft as it heads to court Wednesday to spar with its hometown. The company sued the city and its Municipal Transportation Agency in June, shortly after the agency began soliciting applications from vendors operating free-floating, dockless bikes.

Lyft pointed to its 2015 regional contract with the Bay Area Metropolitan Transportation Commission, in which the company agreed to build a bike rental network across several counties, at no cost to taxpayers. The company said San Francisco reneged on that deal by opening its permit process for dockless bikes to other operators. City transportation officials argued that dockless bikes — which can be stashed at any rack — are a different species of mobility device, not covered by the contract.

Uber, Lyft’s longtime Silicon Valley rival, recently intervened in the case on the side of the city. Uber owns Jump, which has permission to rent red electric bikes on city streets until 10 days after the court rules definitively on Lyft’s request for an injunction.

Schulman’s tentative ruling granted Lyft’s request for an injunction to block the permitting process for dockless traditional bikes — the kind powered by a human pushing pedals. But the judge made a distinction for electric bikes, like the new black-and-pink line that Lyft just rolled out in San Jose and Oakland. For those devices, Lyft is entitled to a right of first offer, Schulman said, meaning the city has to negotiate with the company in good faith before offering permits to anyone else.

A spokesperson from Lyft declined to comment Tuesday. City attorney spokesman John Coté stressed that the ruling is preliminary.

“This is not a final decision, and we look forward to tomorrow’s hearing in court,” Coté said. “The city’s goal has always been to make thoughtful improvements to the transportation network so more people have options to get around in safe, sustainable ways.

As the lawsuit winds through court, street-rental bikes are dwindling in San Francisco’s downtown core. Docks that once brimmed with baby-blue pedal bikes and their black electric counterparts — once known as Ford GoBikes, now rebranded Bay Wheels — are sitting empty.

Lyft pulled its black e-bikes to fix a braking defect in April, then quietly discontinued them and stopped supplying the blue version. The number in its fleet dropped by almost half, from about 2,000 to 1,100. Because of the legal standoff, San Francisco never granted Lyft a permit to roll out its new black-and-pink model. Hundreds of bikes are sitting in a Dogpatch warehouse while bike commuters grit their teeth.

“I’m disappointed they’re suing,” said Cliff Bargar, who rides rental bikes every day from his home in Potrero Hill to Caltrain’s 22nd Street Station. Even if Lyft has a sound legal argument, he added, “I believe competition between (bike-rental) companies is better for people trying to get around San Francisco.”

In other Bay Area cities, the expansion continues: Roughly a hundred new bikes hit Oakland streets on Tuesday.

Rachel Swan is a San Francisco Chronicle staff writer. Email: rswan@sfchronicle.com Twitter: @rachelswan