I ride Conti 4000s 23c tires and always pump to 120-123 psi both front and back. I'm 225 lbs and pump them up to the tires recommended max to avoid pinch flats. So far after thousands of miles I haven't had one pinch flat. (I probably just jinxed myself but oh-well.)

Is there a formula that applies the riders weight to tire pressure that provides a suggested minimum psi that will protect against pinch flats? I'm not racing so a mph or two doesn't make a big difference to me.

Thanks for any input.