To find the right machine for you, be sure to try before you buy. Consider these factors:

Exercise bikes vary in size and shape. When you're shopping for one, adjust it for your size in the store. Look for a comfortable seat and pedals that fit your feet.

We found a few ergonomic and comfort quibbles with some bikes. The Gold's Gym Power 210 U seat can adjust for users up to 6 feet 2 inches, but we found that anyone over about 5 feet 8 inches hit their knees on the handlebars. The Omega Fitness CO-BU130 had handlebars that were a long reach for some. And all of our panelists found the seat on the HealthRider ExerPlay 200 uncomfortable.

Watch the warranties

Look for one that provides at least two to three years of coverage on major moving parts and a year for labor. Survey data on the probability of failure and repair costs showed that extended warranties are probably not a good deal.