The city’s schools chancellor, Joel Klein, is traveling to Albany tomorrow to urge state lawmakers to give him the power to create “unlimited” charter schools in the five boroughs.

In the past, Mr. Klein has endorsed abolishing a statewide limit of 100 charter schools. While he continues to support elimination of the statewide cap, Mr. Klein is changing his lobbying tactic. Now he is suggesting to lawmakers that they exempt New York City from the limit on charter schools, giving the chancellor what his aides have called “limitless” power to authorize new charter schools.

Yesterday, Mayor Bloomberg, standing near his chancellor and the Bush administration’s new secretary of education, Margaret Spellings, told a room of charter-school students that charters are central to his administration’s education agenda. He vowed to pressure Albany to lift the cap.

“One of the problems we have in this state is, because of state law, there is a legal limit to the number of charter schools that can exist, and I don’t know that anybody’s ever come up with a good legal argument as to why we would want to limit the number of good schools that people are willing to create,” Mr. Bloomberg said. “It’s a challenge to all of us to work with the legislators and try to convince them that that’s not really rational and that you deserve choice, that you deserve the ability to go to a better school.”

Later, Mr. Klein called the cap “irrational” and “arbitrary” and told a group of charter-school leaders: “I will fight because I believe in what you’re doing.”

Mr. Klein is scheduled to start his day in Albany with a legislative breakfast. From the city, he will be joined by the director of the New York City Center for Charter School Excellence, Paula Gavin; a director of a newly approved charter school, Girls Prep Charter School’s Mirriam Raccah, and the chief executive of the city Department of Education’s Office of New Schools, Kristen Kane.

After the breakfast, Mr. Klein will meet with the Black and Latino Caucus; the chairman of the Senate Education Committee, Stephen Saland, Republican of Poughkeepsie, and a Pataki representative.

Ms. Kane said Mr. Klein is going to Albany to “explain why he would like to see legislators lift the cap on charters for New York City and, in doing so, create additional high-quality educational options for students and families.”

Although some state legislators and the governor support the idea of lifting the cap on new charter schools statewide, most lawmakers don’t. The chairman of the Assembly’s education committee, Steven Sanders, a Democrat of Manhattan, has said 100 charter schools should be opened and be assessed before lawmakers approve the authorization of more.

It remains unclear how the Assembly and the Senate would react to the idea of getting rid of the cap for the city but not for the rest of the state.

A spokesman for Governor Pataki, Kevin Quinn, said the governor “supports the concept” and in this year’s budget advanced the idea of giving New York City the power to create limitless charter schools. It was rejected by the Legislature.

The president of the Albany-based New York Charter Schools Association, Bill Phillips, said he understands why the chancellor is advocating on behalf of his own school district, but he said his group favors eliminating the cap on charter schools statewide, not just in the city.

The new Bloomberg administration push in Albany comes during National Charter Schools Week, which kicked off yesterday morning at KIPP Academy, in the Bronx, where Ms. Spellings spoke about the importance of KIPP and charter schools nationally.

“For seven straight years, you’re the highest-performing middle school in the Bronx, and you’re in the top 10% of all New York City public schools, and that’s because you are focused on a well-rounded education,” she told the students. “Innovation and achievement go hand in hand. … You’re not here because you have to be here. You’re here because you want to be here.”

She said other cities across the country should learn from New York City, which she called “charter friendly.”

Last night, charter-school leaders from around the city gathered at the Lower Manhattan offices of the Center for Charter School Excellence to brainstorm best practices. It was the first ever gathering of school leaders, who are usually isolated as they launch their new schools.

The center’s chief operating officer, Matt Candler, said charter schools often compete for scarce resources, including facilities, funds, and dedicated teachers. He said last night’s “summit” was an opportunity to “put down our weapons and cooperate as a group.” He said the idea was to help charter-school leaders learn from each other so that the wheel does not need to be reinvented each time a new school is launched.