MODELS

SHORT WHEELBASE -- The frame (average: 69 inches) is about 20 inches shorter than the long wheelbase. But the big difference is the crank set (where you pedal) is ahead of the steering fork, above the front wheel.

• Advantages: More aerodynamic and faster than other models. Because it's shorter, it's easier to transport by car. It's better on hills because of low-speed stability. "You can drop below 5 mph and still keep the bike upright," said Rick Steele, owner of Gold Country Cyclery in Shingle Springs.

• Disadvantages: Doesn't benefit from the use of a fairing, a fiberglass cover that blocks the wind. Because the seat is higher, short-legged riders need to make sure their feet can be planted on the pavement, for safety reasons.

HIGH-WHEEL RACERS -- This is a short-wheelbase bike that improves on speed by elevating the crank set higher and moving the seat back to a 25-degree angle. "This is good for high-end road cyclists used to conventional performance bikes," Steele said.

• Advantages: Small aerodynamic profile leads to better performance.

• Disadvantages: The often-extreme reclined seating bothers some riders.

LONG WHEELBASE -- The frame averages 89 inches. The crank set is behind the steering fork.

• Advantages: The longer frame gives a smoother ride. The frame can accommodate riders whose height ranges from 5 feet to 6-foot-8. Easier on the knees.

• Disadvantages: The laid-back seating takes some getting used to. But most bikes have various recline settings. The long frame takes up more space on the road and is more cumbersome on turns.

TRIKES (THREE-WHEELED BIKES) -- The tadpole design has two wheels in front, one in back. Good for stability and pushing into a corner turn. The delta design has one wheel in front, two in back. Great balance. The rider can sit down on the bike and start riding without worrying about falling off.

STEERING

UNDER-SEAT -- Steering handles are parallel to the rider's hips.

• Advantages: A more comfortable position for the arms, especially useful on long rides.

• Disadvantages: It takes more training to learn how to steer. This style no longer is produced by U.S. manufacturers but is available in Europe.

ABOVE-SEAT -- Steering is similar to a conventional bike, shoulder-level.

• Advantages: People are more familiar with steering.

• Disadvantages: People tend to pull on the steering, as with a conventional bike, thinking it will help their speed, which is not the case.

Frequently asked questions

• Are they difficult to ride? There are variations in handling -- some are fast, twitchy racing models; others are smooth, stable touring models. You use other muscles, mostly the quadriceps.

• Do they "do" hills? Some think that because you cannot stand on pedals, you can't ride up hills. They are slower on hills, but as long as you keep pedaling, the bike keeps moving.

• Are they faster than upright bikes? Most of the human-powered land-speed records are held by recumbent or semi-recumbent designs.

• Are they safe? You sit lower than on an upright bike, so some recumbent riders add a flag on an extended rod or a reflective hazard sign when traveling on heavily-used roads.