Tires were fine. but when the guy almost burned his hand removing the wheel, he confirmed what I suspected: the caliper is sticking (actually, I suspected a rotor problem; close enough for Gov't work!)
That explains why it was happening after driving 15-20 miles: the slide is sticking lightly, and the rotor is heating up. Have a new rotor, new pads, and Dremel tool. This is the one caliper I
*didn't* rework last year, since it was the only one that wasn't sticking!Supposed to be a warm but not too humid evening tonight...