Remember August 4? It was 99 degrees, the humidity like a boulder on the chest.

Surely nobody would show up . . . at 5:30 p.m. . . . after a full day of work . . . to ride a bike.

But at 5:05 p.m. cars and pick-ups crunched into a gravel lot kicking up dust aside the Little Miami Bike Trail in Mason. About 20 people, half over 40 and several over 50, made ready to pedal 25 to 30 miles.

What heat? If ever there was testimony to the resurgence of adult biking this was it.

This group, the Firecrackers, is one of the "clusters" of the Cincinnati Cycling Club arranged by area and ability. Described by Jim Thiry, of Lawrenceburg who works nearby, as "50 percent over 50," and the "preferred" (read slow) group, the men and women meet twice a week averaging about 15-17 mph on the trail and local roads. There are hills or "moderate rollers" in bikespeak, but not to worry, says Thiry. "No one is left behind."

Erik Nelson, 64, of Centerville, a rider whose main hobby is canoeing, is a regular, pushing off at 5:30 p.m. and usually finishing by 8:30 p.m.

Like most Boomers getting back in the saddle, he learned to ride as a kid, in Brooklyn, then let it slide until he and his wife started riding again several years ago.

"It came back immediately. When I first got on there was little bit of clumsiness, getting used to the pedals and controls, but it didn't take 20 minutes to get going," he says.

The adage about "riding a bike "” you never forget" is true, especially if you have the right bike, says Kelly Sullivan of Bishop's Bicycles in Milford.

"Bikes have changed since we grew up. They are built for comfort now. You'd be surprised how many people come in and say the same thing "” that they rode as kids and want to start again. And the Little Miami Bike Trail is perfect. It's safe and convenient."

His advice is "to come in and kick the tires a bit. For awhile you couldn't even buy a ladies' bike," he says. "Now they are built with a shorter reach on the bike frame, handlebars are adjustable, gear-changers are on the handle grips. Now everything comes up to you so you can sit upright."

Bad back? Bad knees? Big frame? No problem.

The new handlebar system that lets you sit upright helps riders with bad backs. Those with hip-and-knee or balance problems can benefit from the new pedal-forward bike so the rider can sit on the bike and easily touch the ground. And recumbent bikes, which put the riders low to the ground in a sitting position with legs extended forward, are popular for active seniors like Thomas Lowell, 56, of Mount Lookout.

The geologist, who describes his knees as "shot," chose the recumbent 27-speed Terra Trike Tour model about three years ago because "it supports my frame better. I wasn't comfortable on a traditional model." Now he zips around the neighborhood streets on the low slung speedster with a "hey-I'm-on-the-road-to' flag hovering overhead on a 6-mile loop for a cardio workout.

"We offer about five different models to start out," says Sullivan.

The cruiser is more traditional, with the fat tires and often a hand or foot brake. They are for the slower ride looking for a very relaxed lazy afternoon ride.

The next step is the hybrid or comfort bike, then the pedal-forward models and then the fitness bike, a cousin to the old drop-down handle racing bike.

"Most people realize they need at least seven speeds, once they try them," he says.

But not Mary Blevins, 58, of Batavia, a volunteer at the Anderson Senior Center. Her son bought her an old-fashioned foot-brake one-speed for her birthday three years ago. She started slowly, taking about 20 minutes to go about two miles around the neighborhood. Nowadays she joins a friend and often her grandkids to polish off the distance "in about eight minutes."

"I lost 85 pounds and I was taking six blood pressure pills a day. Now I'm down to two. The doctor says 'keep up the good work.'"