Checked the tyre tread depths (using my new electronic tread gauge), on my Pirelli P Zero's on my 19" Santiago's.
N/F (Avg) 5.85mm O/F (avg) 6.09mm
N/R (avg) 5.91mm O/R (avg) 5.87mm
Not too bad methinks for over 14k already on the tyres, should easily see 20k. Quite surprised for 19" Ultra low profile tyres (but then I did rotate them fronts to rears at 8,900 miles).