Originally Posted by abdon

I Have tried small tires on 26" rims, lowering the bottom bracket. It does have a negative effect on geometry, significant enough to affect how well it behaves. You can compensate by increasing the trail on the fork but most would be rightfully squeamish at pulling that stunt.

Nobody said overinflating tires. A smaller more road tire on a larger rim leaves the geometry intact. The actual pressure is determined by the scope of the tire (the pressure range) and the weight of the rider. On the same tire my daughter can afford a lot less pressure for the same rolling resistance, my fat ass deforms the tire more under load and requires more pressure. If you want to be technical about it what you are trying to minimize with higher pressure is the road contact and your weight affects how much that contact happens at a given pressure.