Wind trainers are fairly simplistic in function. Basically, it's a fan and roller system that creates resistance so that your indoor training sessions don't have you just spinning your wheels. Before the advent of the wind trainer, you had only a few choices. Ride on rollers, ride an ergometer that didn't replicate your road riding position, or, gasp, train outside. Even when wind resistance units were invented, they featured myriad weaknesses. Kinetic by Kurt addressed the fallbacks of traditional wind resistance units with its classic Cyclone 2. 0 Wind Trainer, one that rides well, travels well, and comes in at a great price. Early wind resistance units were simply 'squirrel cage' fans small diameter, louvered cylinders running off tiny rollers that spun quickly and were painfully noisy when going all out. The units were so light, there was almost no momentum in the unit while riding and the moment you let off the gas, speed would drop to nothing. Another problem was their durability it was too easy to knock the fan out of true or damage the louvers when you traveled with them in your trunk along with other race gear. Working with the idea that they needed to produce wind resistance and have some sense of momentum, Kinetic by Kurt made their roller 2. 5 inches in diameter for easier rolling, less tire wear, and quieter operation. They also decided to work with two fans on either side of the tire roller. Each fan is 6in in diameter and weighs 2. 2 pounds. In other words, they both act to produce resistance and provide momentum. And because of their design and heft, the fan wheels are plenty durable. The noise of the spinning fan blades doesn't become noticeable until 25mph, and at that point you'll be cranking out approximately 349 watts according to Kinetic's wattage chart At the very least, it may instill fear in your competition as you warm up for your next time trial. The frame, green as always, is the same as used with the Road Machine. The base i...