Maybe your downstairs neighbors frequently comment on the whirring and whooshing sound that comes from your condo every night. Or maybe the wind trainer is just getting boring. Either way, the CycleOps Training Rollers will bring the fun back to your winter training miles. Unlike a traditional cycle trainer, where the rear wheel of your bike is fixed, on rollers, the bike glides freely across the width of the rollers. This ability to move laterally requires you to develop balance and core strength in order to keep the bike rolling in a straight line without slipping off of the drums. Additionally, rollers require that pedal stroke and pressure are bi laterally consistent. Why is this important Well, developing a smooth, round pedal stroke not only makes riding rollers easy, but it'll have you at the front of the pack come springtime. The drums of the CycleOps rollers are constructed from precision lathed aluminum. A diameter of 3. 25 inches allows for variance in resistance as you shift gears. Smooth and quiet, they won't distort in heat or sunlight. The rollers are secured to a stiff steel frame that conveniently folds up for easy storage in a closet or even under your bed. To adjust for varying wheelbase lengths, the front roller is easily moved fore and aft. A little tip: if your front hub sits directly or very close over the roller, the length of the rollers is properly dialed in. The resistance belt is adjustable for right or left side use depending on your dismount preference. If you find you need more resistance while riding the rollers maybe you ride a compact gear in the off season, the CycleOps rollers are available with a resistance unit. It's a simple magnetic bar that works within the magnetic field of the rolling aluminum rear drum. It features five settings to allow you to increase the difficulty of your workout without any additional noise. The CycleOps Rollers are available in with or without a Resistance Unit.