I've about 700 miles on Michelin Pro 4 Endurance 23mm. First day STP; after the swarm left the start line and about 1/4 mile out, I drilled about a 9"+ diameter 4" deep concrete chuckhole straight on. The kind of chuck hole with a sharp edge far side & I going about 15 downhill. I weigh 197 and my Colnago's pretty stiff. My buddy saw me hit the chuck hole and I expected a "BAM", but nothing happened. The 115 psi & light hands likely saved the tire, tube, possibly rim, from a nasty pinch. Nonetheless I was impressed though I'm glad that chuckhole wasn't any bigger. After two days of 200 miles comprising various & nasty bridge expansion joints, rail road crossings, chip seal, more chuckholes, glass, etc. I've no complaints.