As a sizing factor is absolutely vital to your safety, comfort, and enjoyment. Bike shop bikes are sized to proportionally fit both your leg length and upper body. Woman s frame style bikes often fit women s longer leg - shorter torso body proportions better than triangular men s frames. Usually, you want to have one or two inches of clearance between your crotch and the crossbar when sizing a road bike, a trail bike, or a hybrid. Mountain bikers often prefer three to six inches of crossbar clearance for standing on the pedals going downhill and because smaller bikes are more maneuverable.
Triangular frames ARE more rigid and flex less than a woman s frame.
An efficient bicycle frame design flexes less, and converts more of the pedaling action into forward motion. Buy a woman s frame style bicycle if that s what you would be more comfortable on and more likely to ride. Bike shops have lots of ways to adjust and alter bikes for tall women who only fit a man s frame, but are uncomfortable with the longer reach to the handlebars.