The Shimano EM810 Rotor gives you ideal braking performance on your eBike as you ride through a huge range of conditions. This rotor features an external spline and a 180mm diameter. On an eBike, heat buildup at the brakes can be a bigger issue than normal, so Shimano incorporated their Ice Technologies Freeza system to reduce heat buildup as you ride. The rotors feature center lock mounting, making maintenance a breeze. The Shimano EM810 Rotor is a great choice for eBike performance.