STURGIS, S.D. ? The thrill of riding a big, bad motorcycle through the Black Hills of South Dakota is drawing thousands to this quiet town, transforming it into a noisy, bawdy road rally that has grown into a three-week spectacle.

“It’s the riding, 100 percent,” said retired sales executive Jerry Boen, of Livingston, Texas, as he dusted off his Harley-Davidson. “When you’ve been to one motorcycle rally, you’ve been to them all. None have riding like this.”

Bikers of all kinds – from hard-core, tattooed enthusiasts to lawyers and doctors – come from every corner of the nation for the annual Sturgis Motorcycle Rally, lured by the twisting, pine-skirted roads of the Black Hills, as well as Badlands National Park and Mount Rushmore.

The one-week rally is scheduled for Monday through Aug. 14, but it has unofficially expanded in recent years to include the weeks before and after. It began in 1938 as a small gathering of bikers and has grown in the last decade or so to attract hundreds of thousands each year.

The rally’s director estimates more than 500,000 people attended the 2004 event.

The droning rumble of motorcycles is nearly constant at all hours during the rally and becomes deafening at times when crowds reach their peak. Thousands of motorcycles are parked, row after row, in the center of Main Street and on both sides. The street is closed to other traffic during the event.

The rally is well-policed and there are few major problems, although the atmosphere is sometimes bawdy. Most arrests are for drinking and driving, drugs or the occasional fist fight.

Jerry Boen of Livingston, Texas, dusts off his motorcycle July 31 at Sturgis, S.D.. Bikers of all kinds, from motorcycle gang members to doctors and lawyers, trek from every corner of the nation for the annual Sturgis Motorcycle Rally. It began in 1938 as a small gathering of motorcycle enthusiasts; last year, traffic counters logged 547,370 vehicles coming into Sturgis during the seven-day rally.

While black leather and jeans are the typical dress, many bikers wear outlandish costumes to attract attention. Concerts are held nightly with big-name entertainers, such as country stars Tim McGraw and Toby Keith and rock bands Journey and the Steve Miller Band this year.

Some bikers just like to stroll down the streets checking out the motorcycles and people, while others drive back and forth in parade fashion.

Sitting with his dog in front of a building at a busy intersection, Eugene Cady, 84, said he enjoys looking at all the different brands and styles of motorcycles. Although his eyesight is failing, Cady said he’d love to drive one of them.

“I rode bikes for 30-some years,” he said. “I just wish to hell I could ride again.”

William Hixon Jr., of Madison, Ohio, stopped here the week before the rally while returning with his travel trailer from several weeks in Alaska.

He said Sturgis, with a population of about 6,400 people, rates above other popular motorcycle rallies, such as Bike Week in Daytona, Fla., because of its small-town nature and excellent riding opportunities in the surrounding countryside.

“For most of the people at other rallies, all they do is ride from bar to bar,” he said.

Not that Sturgis doesn’t have plenty of bars. New ones spring up every year, and the beer flows freely.

Jack Johnson, a motorcycle mechanic, came from Daytona Beach, Fla., to work at a bar during the event. He has been to 26 consecutive Sturgis rallies.

“I come here to drink, too,” he said.

Gary Raabe, 58, also traveled a long distance to attend, riding his motorcycle nearly 400 miles from Denver. A big draw for him is South Dakota’s lack of a helmet law.

“It’s nice not having it mandatory,” he said. “It’s still freedom of choice.”

A retired airline pilot, Raabe tries to avoid the large crowds by coming a week before the official start.

“You can’t move around here during the rally. It’s just too crowded,” he said.