I was hoping someone could tell me if this is a real problem or not on my 2013 Ritz lxi: whenever I use the brakes at more than 10 KMPH, there is no noise and everything is smooth. But when I apply brakes at less than 10 KMPH, there is a low whistling noise that I can hear. It is continuous and not very loud, but enough to attract the attention of motorcyclists riding really close to my headlamps near speed breakers. Any idea what that sound might be? Should I get my brakes checked? Is it due to winter temperatures? I don't recall hearing the sound in the summer.