RT-EM600 E-bike rotors with built in speed sensor magnet providing consistent braking performance through energy control. Rotor houses the magnet necessary for speed sensor function on Shimano STEPS equipped E-bikes allowing frame clearance for wider tyres. Compatible with E8000 / E7000 / E6000 / E5000 systems & for rear wheel use only. Rotors are durable lightweight & rigid, using the proven Shimano Centre-Lock system giving increased strength & security with an easy set-up. Precision cut & drilled braking surface improves pad clearing in muddy conditions while aiding cooling under high load. Large alloy spider is a highly rigid & lightweight support for the rotor surface. This super polished braking surface gives excellent braking performance.