Quote Originally Posted by Seajay View Post
But... Where do you get the fact/opinion that charts are based only on preventing pinch flats?
It's a conclusion (I don't know whether that counts as "fact" or "opinion" ) based on three things:

* the charts don't take into account road conditions;
* the charts don't take into account rider preference for comfort vs. performance; and
* the pressures they give are well below what I need to minimize rolling resistance.

The only reason any road tire needs a "minimum" pressure is for pinch flat prevention. Other factors yield a range of pressures for a given rider weight. Tubeless tires are becoming popular mostly because they allow riders to run much lower pressures than tubed tires.