I'm running GP 4000 S in 700 x 23 on two bikes and GP 4000 700 x 25 on the other. All said over 5000 miles on these tires with almost 3000 on one set that the rear is finally wearing out on. No sidewall issues and no flats on this set.

Today I had wierd incident with one set. Stopped the bike and was standing taking a break when I heard the hiss of a blown tube and the front tire went flat. I should mention this was a Bontrager racelite xxx lightweight tube. No sign of damage, no debris on the road, and nothing in the tire when I changed it. Not sure what caused the flat.

Most of my riding is on rough chip sealed roads. The 700 x 25 set is on my bad weather bike and sees all sorts of abuse on wet and winter roads. I am extremely pleased with them.