I've had some file threads that got a lot of "in and out" flats. Tiny sharp debris gets stuck in the thread and eventually works it's way in through. Don't see how a 4000 would have that problem. I'm going to side with it's random. Me personally, I can go 1000 miles with no flats and then get 4 in 5 rides including both tires on the same ride from different causes.
Last edited by u235; 06-13-18 at 07:16 PM.