Blazing Saddles correctly links tire pressure with tire section. 'High pressure' is meaningless by itself and 55psi - 85psi would not ever be max psi for the same size of tire. 55psi is a high pressure for a 2" tire and 60psi probably the max for most brands regardless of quality though Schalbe tires go to 70psi in the 50mm. A 25mm tire would not even stay on the rim at 55psi. I used to run my 25mm at 110psi. Now I use 80psi or 90psi. No lower. My 2" tires are still functional at 30psi. They start feeling sloppy around 25psi. The recent popularity of larger section (35mm - 47mm) is meant for gravel riding. For 'speed' the small section at very high pressure still cannot be beaten. If you come to a street race with 35mm @ 80psi you are going to be humiliated regardless of how strong you are.