None Bicycle Rear Wheel Trainers
Trainer resistance is available in fluid, wind, magnetic and electronic. Magnetic trainers are most common and have fixed levels of resistance. Fluid trainers have progressive levels of resistance; the harder you pedal, the more resistance they provide. Wind trainers tend to be very noisy, as they generate their resistance from a fan. Electronic trainers require a power source and can often provide the most powerful and precise levels of resistance. They sometimes can include virtual reality interfaces for a more interactive experience.