Does anyone knows for sure how the F12 measures the brake disc wear that the dealer can read out? Is this an actual measurement (e.g. optical thing) or is it an estimation of the computer?
there is an algorithm in the ECU that estimates rotor wear, based on a few inputs that I believe include total mileage, driving habits (eg. number of stops, brake pressure, average speed). IT's calculated. each rotor has a serial number, when you change rotors you actually need to enter the serial numbers into the DEIS (or VCI on the race cars). the empirical way to measure wear is via weight (can't recall offhand the suggested life-out weight). Visually, all you can really detect are cracks, pitting and/or glazing which might also indicate it's time for replacement. Pads on other hand have an actual wear indication FWIW I got an entire race season (testing, practice, races) out of one set of rotors; the next year I barely got half a season before the rotors life'd out. Big difference was the level of braking due to the tracks we were running (and likely me going much faster ha ha).
... that in some cases will indicate only after it's too late. Best check is visual and physical inspecion of pads after any track use. Been there, etc.
Thank you. Do not like it. I have seen a Mercedes patent where they have some patterns in the brake disc and an optical sensor can see the wear of the disc.
