I did read a recent article stating that the Bathurst City Council are re-surfacing the entire track at Mt Panorama, as the existing surface is starting to crack up and they need to do it just to keep the Grade 3 rating.I wouldn't be surprised if the grading is done reactionary to the cars supposed to be racing on the circuit and some of the parameters of the track itself come down to "the vibe" at the time.
I also remember reading an article (a while ago), which stated that Mt Panorama didn't make the Grade 1 standard because of some of the track gradients - most notably through The Dipper.
No doubt there are some technical regulations involved - but I suspect there's a bit of "the vible" also involved.






