The DT Swiss TRACKR SPEED
GPS works by satellites continuously broadcasting their exact position and time, which a receiver uses to calculate its distance from each satellite based on how long the signals take to arrive. Signal dropouts to satellites in challenging terrain might lead to inaccuracy of your data, especially in lower speed (e.g., steep climbs). Our TRACKR SPEED uses a 3-axis accelerometer to determine the rotation of the hub and thus translates every wheel rotation into pure accuracy and speed, even where satellites tap out.