stumbledotcom wrote:All BMW models include a brake drying function. When the windshield sensor detects rain, the brake pads are moved closer to the rotors to eliminate moisture thus reducing stopping distances. BMW USA posted a video explanation in 2012.
I33t wrote:The brakes are automatically applied if the battery is 100% charged, the i3 is being driven and the accelerator is lifted (to slow the car). When the battery capacity is reduced, lifting the accelerator charges power into the battery without applying the brakes.
The i3 still uses the motor for 'regenerative' braking even if the battery is full, rather than the mechanical brakes; it just doesn't go into charging the battery but it certainly helps run the consumers (ie. HVAC & battery cooling/heating). The display still shows kW being generated going downhill with a full battery and I can hear that the mechanical brakes are not being used.
So unless you actually use the brake pedal in the i3, you're not going to be wearing off the layer of rust from the discs. I make a point of using the brakes occasionally (once a week) to wear off the crud. I find doing it when exiting a motorway at high speed, and braking lightly for a few seconds, is more effective than trying to clean it off at slower city speeds and it doesn't kill the speed quite so quickly.