Bicycle computers at good prices from starbike.com
An effective training requires a feature-rich bike computer. Every current computer can display data like current speed, average speed and the distance. Other values like cadence, temperature, altimeter and heart rate can only be found in more advanced bike computers.
These advanced models often come with a PC interface, so that the recorded data can be transfered onto your computer for training analysis.
A leading manufacturer of bike computers is the german company Sigma Sport.