What are these marks on my rear rotor? Pitting? It’s only on this one rotor It has 50 k miles on it I measured the rotor thickness and it’s 20.1mm and service manual says minimum allowed is 10.4mm but I measured using a vernier caliper and given the lip can I reply on this reading? how would you measure with a micrometer screw gauge? as mine only goes up to 10mm max rotor still has a lip Any harm in driving like this?