Disc Brake Speed Sensor
The EW-SS301 Disc Brake Speed Sensor is the disc version of the EP8 series speed sensor.
Instead of using a spoke magnet it uses a disc brake rotor magnet. It isn't mounted to the chainstay, but screws into the frame instead. The EW-SS300 is the chainstay mounted alternative..
Shimano have a couple of speed sensor magnet equipped rotors available:
- RT-EM910 - 203mm / 180mm / 160mm
- RT-EM810 - 203mm / 180mm / 160mm
- RT-EM300 - 203mm / 180mm / 160mm (for use with resin pads only)
- RT-EM600 - 203mm / 180mm 160mm (for narrow type brake pads only)
The sensor comes with a fixed length wire attached. You can get them in two different sizes: 760mm and 1400mm.