The wahoo blue sc connects wirelessly to your ios or select android device and tracks your cycling speed pedaling cadence and distance through the free wahoo fitness app and other popular ios apps such as cyclemeter strava mapmyride and runtastic road bike the blue sc mounts on the rear chain stay and uses spoke and crank magnets to track bike speed and pedal rotations per minute gps speed and distance data can be inaccurate and unreliable the wahoo blue sc measures cycling speed distan