Tire rotation

It's possible that the back tires were feathered on the edges and when they were cross rotated to the front they turn the opposite direction and the feathering will make more noise. You can either live with it or swap the fronts from side to side. This is one reason why I will no longer cross rotate tires where I work, too many complaints from people. If people would rotate the tires more often, this would not be an issue.

Ian

Get a good 4 wheel alignment - you LIKELY have an alignment problem on the rear that is cupping the tires. As Shien_kai has stated, moving side to side may help. I NEVER rotate tires left to right.

On my own vehicles they get rotated front to rear every spring and fall when I take them off to replace them with the opposite season specific set.

I thought the rule with radial tires was that you never moved them side to side, only front to back. 30 years or so ago I was warned that the steel in a radial would "set" in whatever rotation and if you reversed the direction by moving it to the opposite side it would cause the steel belt to cut its way loose as it tried to set in the other direction.

Having had two tires had the tread seperate at the level of the steel belt, I expect that someone knew something when they told me not to move radials side to side. Modern glass belted tires may not be subject to the problems that steel belted radials had.

Or do they even use glass belted radials anymore? Since I went to driving less than 1500 miles a year, I only replace tires when they have sidewall rot, and right now the newest tires on my car are over 7 years old, the older pair are more like 10 years old.

Possibly, but I wouldn't hold my breath.

Ian