The front and rear thing are not necessarily the same device. The rear thing looks like a rubber hose or grip zip tied over something to protect it. Might be an accelerometer, quite large for one tho. Could be a wheel speed sensor, or a pressure transducer for brake force? The way it's sticking up so far might be relevant. If its a post mounted to the frame rigidly with an accelerometer at top and bottom and a front triangle mounted one, they could compare the readings to to see how much torsional flex is occurring in the frames rear...