A method is disclosed of writing product servo sectors to a disk of a disk drive to define a plurality of product servo wedges, the disk comprising a plurality of spiral tracks. The spiral tracks are spaced apart circumferentially by a substantially equal spacing, and the number of spiral tracks equals a non-integer multiple of product servo wedges. The head internal to the disk drive is used to read the spiral tracks to generate a read signal, and the sync marks are detected from the read signal to generate a sync mark detect signal. A timing recovery measurement is generated in response to the sync mark detect signal, and a frequency control signal is generated in response to the timing recovery measurement. A servo write clock is generated in response to the frequency control signal which is used to write the product servo sectors to the disk.