The Wattbike is extremely accurate. The amount of power produced is calculated from the force applied to the chain through the cranks (sampled 100 times a second).
Each Wattbike is factory calibrated and is accurate to within +/- 2% over its full range.
During his time with British Cycling, Peter Keen worked with Wattbike to design a truly unique indoor trainer. Developed in a world class environment, the Wattbike allows everyone from complete beginners to Olympic and World Champions to experience the same ultimate training tool.
The Wattbike is the first indoor bike that actually feels like riding a bike. This is achieved by the unique air brake construction that allows the flywheel to keep spinning like the wheels on your road bike.
The Wattbike is also designed so that you can replicate the setup of your road bike exactly on the Wattbike.