Bicycle rollers follow the same general design: three cylindrical drums housed on axles inside a rectangular frame. Two drums support the back wheel, and a third supports the front wheel; the front and back drums connect with a rubber belt.
Roller frames are typically made of steel or aluminum. The belt is made of rubber, and the drums are made of PVC or aluminum. PVC materials are less durable and require periodic replacement depending on the number of miles logged on the trainer, but bicycle rollers are largely maintenance free. Depending on the manufacturer and materials used, a set of rollers costs between $250 and $400; modest models cost as little $170, and high-end versions can retail at more than $1,000. Most models weigh between 20 and 30 pounds (about 9 to 14 kilograms).
Typically, variation in the roller's design changes the roller's resistance. Kreitler Rollers, a 39-year-old specialty brand, sells rollers with drum diameters of 4.5 inches (11.43 centimeters), 3 inches (7.62 centimeters) and 2.25 inches (5.72 centimeters). A smaller diameter means more resistance: Pedaling at 20 miles per hour (32 kilometers per hour) requires approximately 126 watts of energy on 4.5-inch rollers, 176 watts on 3-inch rollers and 239 watts on 2.25-inch rollers [source: Kreitler Rollers]. Many companies also sell accessory kits that connect the rollers to self-powered fans to create additional resistance.
Tim Fry, president of Mountain Racing Products, which now owns Kreitler Rollers, says that the standard width of a roller drum is approximately 15 inches (38.1 centimeters). Manufacturers offer narrower drums for travel-friendly models or for cyclists looking to challenge themselves by pedaling on a reduced area [source: Fry]. (Some riders simply mark off a reduced area on standard rollers with masking tape.) While most drums are straight all the way across, some manufacturers produce rollers with a concave, hourglass shape to automatically steer the cyclist toward the center and make driving off the rollers less likely. A new variation is the E-motion Roller manufactured by Inside Ride, Inc. It boasts a floating frame that moves underneath the tires, sliding back and forth as the cyclist moves his or her body.
Next, get back in the saddle and read on to learn the basics of pedaling on rollers.