Originally Posted by Chris_in_Miami

I believe the theory (or a gross oversimplification of it) is that a tire at high pressure loses speed more due to deflection over bumps in the road surface, whereas a "softer" tire flows over imperfections without decreasing speed. It seems counterintuitive if you've always believed that a tire at high pressure is always faster, but Jan Heine from BQ has done quite a bit of real world testing...