Chattering When Braking Slowly At High Speeds

[timzter]

I have been driving my 2013 ES 350 for about 9+ months now. Odometer reads less than 7000K. Recently I noticed that when the car is moving at 55-60 mph and especially if the road is somewhat in a downward incline, when I apply the brakes gently to slow down, I can feel the wheels (?) / undercarriage (?) / whatever sort of chatter and vibrate. When I take my foot off the brake pedal, the chattering stops. At low speeds, the behavior is less or not apparent. Anyone else noticed that too? What do you think that is due to?

[bearone]

Sounds like it might be out-of -round or warped rotors.

Good Luck