Senior technician Dave took the car for an extended drive to figure out the cause of the SportCross's woes. Unlike many technicians in car dealers these days, Dave, an ex-TWR mechanic, could hear the symptoms and was able to pinpoint what was causing the sounds. The rumble during braking was due to the pads being part-worn; in that state they lose the chamfer they have when new, thereby creating a larger friction surface against the disc. Mix the IS300's big discs with the worn pads and you get the offending rumble.

The other noise, the one that seemed most like a bearing, was simply tyre roar of a volume and pitch you really wouldn't expect of a Lexus. Just to make doubly sure, Dave jacked up the front end to spin the wheels. His suggestion, should the din get too much, is to swap the present Yokohamas for a set of Bridgestones. All dealerships should have a Dave.