Rode 20km on these tonight at 60psi and it felt nice and comfy...felt a bit weird when climbing out the saddle though...tyre pressures confuse me a little, is there a set rule to rider weight/tyre size and optimum pressure?
Easy answer-no.
just trial and error, what you find comfy without tyre squirm. What you find comfy and what I find comfy may be completely different, I run 28s for commuting at about 80psi, ran 32s at about 60-65psi, 35s at 50psi.
https://www.youtube.com/watch?v=a01QQZyl-_I
Rode 20km on these tonight at 60psi and it felt nice and comfy...felt a bit weird when climbing out the saddle though...tyre pressures confuse me a little, is there a set rule to rider weight/tyre size and optimum pressure?