Originally Posted by
bradtx
I don't think it makes a difference where the magnet is mounted. The magnet will pass the sensor in the same time interval whether near the hub or near the rim. The magnet is going faster when near the rim, but still attached to the spoke.
Brad
Right. So long as the magnet triggers the sensor each and every time it makes a pass you should get an accurate speed reading, provided you have programmed the wheel+tire size correctly.
I've mounted the sensors on the fork near the hub, in the middle, and near the brake (depending on what arrangement is easiest to fit) without accuracy problems. For the wireless sensors you would think that closer to the readout head (the "receiver') would be better, everything else being equal, but I haven't found that to be a real issue. One might also think that the position of the readout (on the same side of the bars as the fork sensor) would be an issue, but again it doesn't seem to be.