Despite the imposing rain clouds building throughout much of yesterday afternoon, Harvard Square hosted the last leg of what organizers called a successful Atlantic Cup Classic bicycle race, with over 150 participants and a throng of enthusiastic spectators.

The bicyclists pedaled 50 times around the Square to complete their 35-mile course, starting at Mass. Ave. and working their way through Quincy Street, Broadway Avenue, and around the Yard.

Yesterday's event was the culmination of a six-race series that hopped from one New England location to the next. Cyclists pedaled in North Hampton, New Bedford, Providence, Salem and Somerville before ending up in Cambridge.

Atlantic Cup coordinators and participants said they were happy to have included the Square in this year's series.

"Harvard Square is spectacular," said race director Paul M. Salvucci at yesterday's event. "It was a great grand finale venue."

Cyclist Jim Copeland from Colorado Springs, Colo. said he especially appreciated the crowds that cheered on the racers.

"It's fantastic--it seemed like the crowd really came out and enjoyed the event," he said. "That's what makes it fun--people watching you."

Mark J. McCormack, a native of North Easton, won the last leg of the race with a time of 1:18:18.

McCormack, who said that he and other bikers used this event to train for upcoming races, said he appreciated the Harvard crowd.

"We're sort of performers in one respect," McCormack said. "To win in front of a crowd makes it that much more exciting."

But some community businesses were not as positive about the event taking over their sidewalk space.

Patricia C. Machado, an employee at Serendipity, said the noise from the race announcer's microphone made it hard to conduct normal business transactions.

But other businesses say the event hurt more than just their ears.

"It actually lowered sales," said one employee at Toscanini's Ice Cream and Coffee.

He said that by 3 p.m. Toscanini's sales totalusually reaches about $600, but today at 3 p.m.they had pulled in only $479.

A Bob Slate Stationers employee said his storehad a slow day as well.