Pact Reached On Skyscraper Built Too Tall

A dispute between New York City and the developer who built a mid-Manhattan skyscraper 11 feet too tall has been tentatively settled, with the developer agreeing to construct rehearsal space, cut down parapets and drop his lawsuit against the city.

The solution, announced yesterday by both parties, will cost the developer, Ian Bruce Eichner, more than $2 million, according to his lawyer. But the outcome is not as dramatic as if Mr. Eichner had been forced to remove the offending 11 feet from the top of the 72-story Cityspire skyscraper at 156 West 56th Street, east of Seventh Avenue.

The rehearsal space would be paid for and finished by Mr. Eichner and delivered to the city at no cost. The city, in turn, would make it available to nonprofit dance groups. The settlement would actually add floor space to the overall Cityspire project, adjacent to the City Center of Music and Drama. Koch Is 'Delighted'

''This appears to be a creative resolution to a very difficult situation,'' Mayor Koch said in a statement, ''and I am delighted that the not-for-profit dance community would be the beneficiary of some desperately needed rehearsal space.''

The City Planning Commission had refused last December to grant retroactive approval for additions to Cityspire that resulted in a building whose top and set-back ''shoulders'' exceeded the dimensions set by city planners and approved by the city's Board of Estimate in 1985.

The chairwoman of the commission, Sylvia Deutsch, said at the time that the panel had been unable to find that Cityspire's additional bulk would ''relate harmoniously to all structures or open space in the vicinity in terms of scale, location and access to light and air.'' A 'Reasonable' Settlement