265/35R19 are considered properly mounted on anything from 9"-10.5". 9.5" is what they put it on to take the official measurements, and would be considered the "ideal" width for that tire.
To most people, a 265/35 on a 10.5 would look a bit stretched, though not dangerously so.
I have accepted a new position at Tire Rack and am no longer in the sales department. firstname.lastname@example.org
is available to assist with M3 questions.