Wearable wireless untethered dead reckoning electronic sports device for a bicycle comprising a weatherproof body, such as an IPxy body, in the body a power source, in electrical connection with an integrated circuit, the integrated circuit comprising a global positioning sensor adapted to receive input from a global navigation satellite system, and an inertial measurement unit, wherein the IMU is adapted to provide filtered output, and wherein the IMU and global positioning sensor are fused to provide a fused output, wherein the fused output comprises yaw, wherein in use a clock time of the global positioning sensor and IMU is synchronized and/or provided with a time mark, a central processing unit for processing data from the integrated circuit and for receiving input from the IMU and global navigation satellite system, the processing unit comprising a transceiver for wireless communication with a remote device, a memory, such as for storing data and for pre-use configuring the device and the information displayed, a comparator for comparing physical changes, such as changes in speed, in altitude, in user power, in location, in distance, in user heart frequency, and in movement frequency, a programming protocol, such as a user interface, optionally a power booster, an accelerometer and/or a gyroscope, optionally a damper, optionally a thermometer, a clock for generating signals in a frequency range of 1-10.000 Hz, a magnetic compass, optionally a barometer, and an antenna, and integrated in the body a display, wherein the body has a detachable fixing means for attaching to a weatherproof body, such as an IPxy body, in the body a power source, in electrical connection with an integrated circuit, the integrated circuit comprising a global positioning sensor adapted to receive input from a global navigation satellite system, and an inertial measurement unit, wherein the IMU is adapted to provide filtered output, and wherein the IMU and global positioning sensor are fused to provide a fused output, wherein the fused output comprises yaw, wherein in use a clock time of the global positioning sensor and IMU is synchronized and/or provided with a time mark, a central processing unit for processing data from the integrated circuit and for receiving input from the IMU and global navigation satellite system, the processing unit comprising a transceiver for wireless communication with a remote device, a memory, such as for storing data and for pre-use configuring the device and the information displayed, a comparator for comparing physical changes, such as changes in speed, in altitude, in user power, in location, in distance, in user heart frequency, and in movement frequency, a programming protocol, such as a user interface, optionally a power booster, an accelerometer and/or a gyroscope, optionally a damper, optionally a thermometer, a clock for generating signals in a frequency range of 1-10.000 Hz, a magnetic compass, optionally a barometer, and an antenna, and a power source, in electrical connection with an integrated circuit, the integrated circuit comprising a global positioning sensor adapted to receive input from a global navigation satellite system, and an inertial measurement unit, wherein the IMU is adapted to provide filtered output, and wherein the IMU and global positioning sensor are fused to provide a fused output, wherein the fused output comprises yaw, wherein in use a clock time of the global positioning sensor and IMU is synchronized and/or provided with a time mark, a central processing unit for processing data from the integrated circuit and for receiving input from the IMU and global navigation satellite system, the processing unit comprising a transceiver for wireless communication with a remote device, a memory, such as for storing data and for pre-use configuring the device and the information displayed, a comparator for comparing physical changes, such as changes in speed, in altitude, in user power, in location, in distance, in user heart frequency, and in movement frequency, a programming protocol, such as a user interface, optionally a power booster, an accelerometer and/or a gyroscope, optionally a damper, optionally a thermometer, a clock for generating signals in a frequency range of 1-10.000 Hz, a magnetic compass, optionally a barometer, and an antenna, and integrated in the body a display, wherein the body has a detachable fixing means for attaching to