I'll try and find the temp ranges. The most common starts around five hundred. As already said we paint the edge of the disc with about twenty m.m. of each colour in a traffic light system, green, orange then red. (more of a pink actually.) The paint is fairly quick drying and turns white and stays that way once the temperature is reached. (Between races it is easily wire brushed off and re-applied). I always paint the discs as part of my race prep. We don't always need the information it gives us but it does come in handy when for example a brakes operating temperatures are not reaching or are over the operating temperature ranges and can help with identifying sticking calipers etc. etc.
