I have been inflating my tires 700x20c 120psi for a long time. Lately I wanted to experiment a little lower pressure for comfort. I reduced it to 100psi. It was working for a while. Then today, after work I went to ride my favorite hill climbing. On the way, I had to go through a street full of gravel falling down from the hill running along side of it. I hit a small gravel, then I heard familiar sound of air coming out of the tube. It was a short course, so I didn't bring my pump, only CO2 cartridge. To make long a story short, I walked back to my house about 3.5 miles.
The tire is rated 100psi recommended. I guess that applies only to smooth road. I had never had flat even I hit a gravel with 120psi in the tire, at least not from snake bite. I'm relatively light weight of 140 lbs. I have been hearing other people with heavier weight inflating their tires 90 tp 100psi in this forum. Are you sure, you really don't get snake bite with those tires? From now on, there will be no experiment for me. 120 psi or higher, I can take a little harsh ride, it doesn't bother me.