I'm a big fan of well-written children's/YA lit. Even better if there are strong WTF characters, and even better than that if there are bicycles involved! The bicycles here only make a cameo appearance, but The Mysterious Benedict Society and the Perilous Journey, by Trenton Lee Stewart (Little Brown, 2008), does meet all of these criteria.

A brief overview: there’s a bad guy (and his cronies) and a good guy (and his team of butt-kicking child geniuses). The kids are meant to go on a scavenger hunt, just for fun, but things get complicated when the good guy, Mr. Benedict, is kidnapped. Instead of going on their original scavenger hunt, the four protagonists follow Mr. Benedict's trail on a rescue mission.

The cast of characters: Kate Weatherall, George “Sticky” Washington, Constance Contraire, and Reynie Muldoon. Reynie is the leader of the bunch—the facilitator and glue who keeps everyone working together. Sticky is a walking encyclopedia; Constance, a precocious three year old whose stubbornness saves the day. Kate is handy with a rope, a screwdriver, a knife, and everything else she carries in her trusty bucket and capable of physical feats I can only dream of. (She runs fast, climbs walls, crawls through heating vents, does acrobatics, and rides a bike.) Definitely my favorite character, Kate is always ready to kick ass and save the day.

A group of unescorted minors relies a lot on public transportation. Let’s skip right to the part where they’re in the Netherlands and they rent bikes.
"Constance rode in a metal basket on the front of Sticky's bike, her legs hanging over the basket edge. The metal pinched her and she felt considerably squashed, but she wasn't complaining. She'd never ridden on a bicycle before and was experiencing, for the very
first time, that rare and wonderful sensation of soaring that can occur--especially on a
cool, sunny day, and especially when no pedaling is required. For Constance the ride was
like coasting down one long, gentle hill, with the breeze fluttering in her ears. She
even rather liked her helmet, a sparkly red dome that made her look like a lollipop. It was impossible not to smile." (192)
Kate, of course, is busy periodically "[whipping] her bike around to face the others, beaming at them as she rode backward, then [whipping] it forward again and [speeding] ahead." (193) This girl would win an alley cat, no problem.

I love the description of Constance here. She's normally cranky, but now she's experiencing biking for the first time and she isn't complaining, even though she's "considerably squashed!" Her experience embodies some of my favorite things about biking: the freedom of movement and the feeling of soaring along. We even have the cool, sunny weather right now.