I'd try changing tires, worked for me.
Possible causes of popping/grinding noises when turning:Wheel bearingsCV joint / axleBrakesSee "Related Questions" below for more
check your wheel bearing / hub bearing assy
Brakes
it could be a wheel bearing that is bad or it could also be busted belts inside a tire
not sure sound like it comes from front suspension
Bad wheel bearings usually cause a grinding noise, and are known to only cause it when turning.
most grinding noises that come from turning is usually a cv axle that needs to be replaced. Can also be a bad wheel bearing. If you hear the grinding when turning to the right then the left front wheel bearing is bad.
wheel bearing?
Bearings, cv shaft, or brakes.
It could make a grinding type noise when moving slow. A "whirrr" type whine when moving faster. The grinding noise may change to a clunking noise when turning the wheel. Any of these noises means "fix me now or else."
i hate answers.com
A 2003 Lexus with an intermittent grinding noise might mean that there is a tire rim rubbing on the brake disk. It could also mean that a tire is rubbing on a fender wall when turning.