Why is there a difference between boys' and girls' bikes?
Dear Straight Dope:
Assuming you're male, and you learned long ago as a young boy how to ride a bike, I'm sure this has happened to you probably more than once, too! I'm speaking of the gruesome incident of getting "racked in the nuts" when getting off a bicycle seat and landing one's family jewels on the horizontal crossbar of the bike. However, as all us boys have noticed, girl's bikes don't have horizontal crossbars. Rather, they curve downward, making them incapable of causing these unfortunate incidents involving the crotch. Girls can't get "racked" because they don't have testicles (duh!). Nonetheless, it appears that bikes have been designed with structural gender differences. But why? What is the purpose for the different crossbars? Is it for physical gender differences like center of gravity? Is it for simple differences in male/female aesthetic tastes? All I know is, if the imposed crossbar situation was opposite from what it has come to be, or if all bikes were designed as "girl's" bikes, a lot of masculine anguish could have been avoided.
I assume by "girl's bike" here you're not referring to the Harley Sportster 883.
The old-fashioned step-through frames on girls' bicycles were simply designed to accommodate skirts and dresses. Like riding horses sidesaddle, this doesn't make much sense anymore. My first "boys'" (read "real") bicycle was a classic brown Schwinn Varsity ten speed. I hit a road grate once and did a crotch-smack on the top tube and granted it didn't make me throw up like I saw my brother do once, but Ay Chihuahua did that smart. I've been told I have balls, but I'm glad I don't have that kind.
Except for the geriatric set who may have a harder time lifting a leg over the bar, most women and men ride bicycles with top tubes now because it makes for a stronger frame. Until recently, women riders had to buy bicycles simply according to their size/height because the adult designs were all unisex. Now a few manufacturers, most notably Trek, are making women's specific frames--with top tubes. Trek used specs from female bike racers to design bicycles for women, who among other differences tend to have shorter arms and torsos and a different hip placement than men.
Back to your concern about your cojones: BMX bikes and some mountain bikes have a slanted crossbar that attaches lower on the seat tube and thus poses less of a threat to the testicles if you suddenly have to bail or put both feet down. This is an important feature if you're racing or riding on uneven, rocky terrain. A lower top tube does put some torque on the seat tube which can weaken the frame, but with higher-end, better made bicycles, this isn't really an issue. So get one of these and your huevos might be a little safer. Plus you won't have to yank out the pink handlebar streamers and scrape off all the Little Pony decals.