I recently had a pair of brand new and a pair of 'slightly used' tires put on my truck.

The shop put the brand new ones up front.

Well, there was enough of a size difference to cause the TOD to act up. I felt a vibration or buzz as I was driving, the next day I had them swap front to rear, and the problem went away.

My logic is that putting the 'larger' (new) tires in the front actually forced the TOD to constantly compensate for the slower rotation.

Switching them alleviated the problem.

But I am ordering 2 more new tires just to be on the safe side.