Coming into the fold

Collapsible bikes have come a long way recently. These four perform like traditional bikes and can fit in small spaces.

Note: These bikes were tested by Times staff writer Geoffrey Mohan.

MONTAGUE PARATROOPER

This bike was built for military use, hence its rugged looks. You need to remove the front wheel, but it will fit in the trunk of a compact sedan. Low-budget components keep the price down, but the ride suffers. The bike’s on the heavy side at 29 pounds. $645 to $695. $645 as tested. (800) 736-5348, www.montagueco.com

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AIRNIMAL CHAMELEON

A true racing steed, particularly so with 24-inch wheels and carbon fork. Rear shock smooths out ride, but bobs. Triple crank makes it ready for any hill. Packing system is more buttoned-down, with more space for helmet and shoes. $2,100 to $3,600. $2,650 as tested. (415) 383-6366, www.airnimalusa.com

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BIKE FRIDAY

This Pocket Rocket Pro model is the closest to a racing bike and probably is still the design to chase. Stiff, responsive and fast. But 20-inch wheels and long stem made for sketchy handling in stiff crosswinds. Spend more and get the carbon fork for a smoother ride. $1,895 to $5,215. $3,100 as tested. (800) 777-0258, www.bikefriday.com

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BIRDY BIKE

Awkward folding and weight don’t add much convenience to this sidewalk-cafe scooter, and a giant front chainring at 56 teeth seems designed for German cycling powerhouse Jan Ullrich -- don’t try it

in San Francisco. $990 to $1,490. $990 as tested. (877) 247-3987, www.birdybike.com