A year ago Alisa Clickenger helped organize a cross-country motorcycle trip for women to commemorate the 100-year anniversary of a most amazing ride by two sisters from Brooklyn, New York.

The Sisters' Centennial Motorcycle Ride honoured the exploits of Augusta and Adeline Van Buren, who in 1916 rode motorcycles more than 5,000 miles (8,000 km) across the country to prove that women could be military motorcycle couriers, able to endure long distances and harsh conditions as well as men.

For Clickenger, it was a breakthrough.

"The ride was important to me," Clickenger said. "It was the realization of a long-held dream of mine to lead a group of women across the United States on motorcycles. Seeing nearly 250 women on motorcycles in my rearview mirror riding over the Golden Gate Bridge was epic -- something I'll never forget. It was very emotional for me."

The ride also helped Clickenger demonstrate what her fledgling company, Women's Motorcycle Tours, could accomplish.

"For me, part of riding motorcycles still is the challenge of embracing the unknown, the mastery of machine and also facing my fears and meeting the challenges of an extended motorcycle adventure," said Clickenger, whose company focuses solely on tours for female motorcyclists. "It was the first time I've seen so many manufacturers (Indian and BMW among them) come together for a common goal -- promoting women and motorcycling. It was wonderful."

Women own about 14 per cent of registered motorcycles, up from 8 per cent in 1998, according to the Motorcycle Industry Council's latest numbers. But Genevieve Schmitt, founder and editor of online magazine "Women Riders Now" , says those numbers count only new registrations. She says women comprise nearly 25 per cent of those who ride (including passengers), and that makes them major players in the riding business.

"Personally, I feel we've kind of seen an exponential growth in the 11 to 12 years that I've had the site," Schmitt said. "There is a whole new market of young girls in their 20s who have taken up riding that we haven't seen, really, in history."

Why are more women taking up motorcycling? Schmitt calls it the "copycat effect. A woman sees another woman riding a motorcycle and says, 'If she can do it, so can I!"'

Manufacturers such as Harley-Davidson produce entry-level motorcycles but it can still seem "intimidating getting on a powerful vehicle," said Pam Kermisch, a novice rider who works for Polaris, the company that owns Indian and Victory motorcycle brands. "I did all the classroom stuff. That's one thing, but it's another thing to actually get on and do it. Once you do it, it's very doable. I think for a lot of people, that's the scary part. I think the second piece of it is that in order to get confidence you have to do it more."

Which is where Clickenger, who lives in Diamond Bar, California, but is on the road most of the time, comes in. Like just about everybody who rides a motorcycle, she identifies with the credo that the only way to travel is on two wheels. In March, she organized an all-female motorcycle tour of Cuba. That will be followed by the Colorado Backcountry Discovery Route during the last week of July and a tour of the American Southwest in October departing from Las Vegas.

"My company tagline is life-changing experiences on two wheels," Clickenger said. "The bottom line is it's about empowerment, and the feeling of freedom -- freedom from our fears, freedom from societal constraints, freedom from our own self-constructed, pre-conceived constraints and breaking those boundaries."

Clickenger says she isn't concerned that catering to women limits her company's potential. In fact, that's the ulterior motive to her venture.

"The joy I finding bringing women together to ride and explore and become empowered through mastery over machine is what drives me," said Clickenger, who figures she's ridden at least 250,000 miles (400,000 km), including a seven-month solo trip from New York to Argentina. "It's been really fun watching the ripple effect, how the cross-country trip affected them and their self-perceived limitations about what's possible for them in their own lives."

Next year, Clickenger will offer several tours, including a motorcycle adventure in southern Africa dubbed "Waterfalls and Wildlife ." She also plans a series of weekend retreats in San Diego, San Francisco, and Sedona, Arizona, and two teaching tours for women just getting started in touring on two wheels, as a way to inspire them to take big trips on their own.

Diane Huston, who served in the Middle East during a 20-year career in the Air Force, is long past the learning stage, and she wasn't deterred after the first ride on her new Harley-Davidson in 1995 ended up in a swimming pool. The lure of the open road is a powerful thing.

"To me, riding a motorcycle is an absolute brain dump with the freedom of wide-open spaces," said Huston, who was on the centennial ride, toured Cuba, and hopes to go on Clickenger's Africa tour next year. "I do hope that women we encountered along the way have become empowered themselves to realize that no matter what we desire, we can have it. We just need to do it, against all odds."