A disk drive is disclosed comprising a disk and a head actuated radially over the disk. The head is positioned over a first radial location, and a first data tracks per inch (TPI.sub.--1) is selected for data tracks recorded near the first radial location. The head is positioned over a second radial location, and a second data tracks per inch (TPI.sub.--2) is selected for data tracks recorded near the second radial location. The head is positioned over a third radial location, and a third data tracks per inch (TPI.sub.--3) is selected for data tracks recorded near the third radial location. A geometry of the head is estimated in response to TPI.sub.--1, TPI.sub.--2 and TPI.sub.--3.