Have a look at this: Tyre Pressures
Makes a change from a tyre thread (ok for you 'mericans, tire)...
The tyre pressure increasing on long rides probably explains why "I" seem to ride better after a few hours. Probably not me at all, just the tyres approaching optimum pressures and temperatures. I usually start out at 37/41, so might be a bit light as I am usually loaded up pretty much, for long trips.