Once the quirky love object of obsessed cyclists who couldn't travel anywhere without getting their ride in, the funky-looking folding bike has morphed into an everyman's transportation solution -- a fast, easy way to get to work and around town. These bikes don't just help you skirt painful airline bike-luggage fees; they collapse in seconds to carry-on size after you've pedaled to the subway, bus or carpool van. And when you get where you have to go, forget about locking the bike to a tree or a railing; just fold it, head up the elevator or stairs and set it quietly in the closet. It's as utilitarian as a jacket or an umbrella -- that you use for a 20-mile workout during the weekend.
-- Roy M. Wallack Tiny size, big-bike feel
Birdy II Monocoque: High-performance, dual-suspension nine-speed with 14-inch wheels and unique instant-folding design.
Likes: Requires more of a big-bike lean-forward riding position than the Abio and Dahon. That, plus the wide-geared drivetrain and the shock absorption on both wheels makes the Birdy more comfortable over long distances. An adjustable-height stem allows more of a custom fit than the two other little bikes. Weighs 23.4 pounds.
Dislikes: The folded Birdy is more cumbersome to lug than the Abio and Dahon but easier than the SwissBike. No quick-release on the rear wheel; you need a wrench.
Price: $2,125. (503) 391-7602; www.birdybike.com.
Roy M. Wallack is the author of "Bike for Life: How to Ride to 100."
Folding mountain bike
SwissBike XO: Full-size, 26-inch-wheel, front-suspension mountain bike that folds at the top tube/seat tube juncture with a quick-release handle.
Likes: The familiar fit, secure feel and versatility of a standard bike with a high-end, 27-speed drivetrain. The RockShox Recon suspension fork allows for real mountain biking. Bike folds in half within seconds. Fits easily in a trunk when the front wheel is removed; both wheels have quick-releases.
Dislikes: Is far more cumbersome and unwieldy than the other bikes when folded, because the wheels don't line up side-by-side as with the Abio and Dahon. Folded, it won't lean balanced against a wall, the front chain rings scrape on the floor, and it is an effort to hold it while seated or standing on a bus. Removing the front wheel reduces the imbalance but leaves the chain rings scraping and adds another loose part to hold onto.
Price: $2,299; lower-end LX model with same frame is $899. (800)736-5348; www.montagueco.com.
Simple and sleek
Dahon Mu Uno: Simple, cable-free, single-speed bike with 16-inch wheels, fenders, coaster brake and hidden air pump.
Likes: A fast fold-up design similar to the Abio, but done with an elegant form, finish and feel that drew admiring comments from the neighbors. The quick-release junctures are smoothly integrated on the Uno; you won't catch your clothing or cut your flesh on sharp edges. To use the convenient air pump, unlatch the seat-post quick-release, pull out the valve hose and pump handle, and pump away. Very light and nimble at 22 pounds.
Dislikes: Old-fashioned coaster brakes instead of hand brakes greatly reduce safety. Lack of a rear-wheel quick-release means you need a wrench. The handle of the hidden air pump can drag on the ground if a cheap plastic ring that is friction-jammed into the bottom of the seat-post tube falls out.
Price: $549. (626) 305-5264; www.dahon.com.
Look ma, no chain
Abio Penza: Shaft-drive three-speed with 16-inch wheels, fenders and rack; tool-free midframe folding mechanism.
Likes: Rides great. Pairing a shaft-drive and an internal-geared Nexus hub eliminates the greasy chain and derailleur, keeping fingers and clothes clean as you fold the bike. It takes just 15 seconds to unlatch the midframe buckle, drop the seat, kick up the kickstand and fold up the pedals and frame.
Dislikes: Pray you never get a flat on the rear tire. It's a monumental hassle to get the rear wheel off, entailing the removal of numerous bolts and the fender and rack. There's no quick-release on the front wheel, so take a wrench. Also, the shaft drive makes the bike, at 30 pounds, far heavier than the others.
Price: $790. (646) 827-0892; www.abiobikes.com.