When I get back or maybe even tomorrow, I'll set them at
26 front and 25 back for a couple of 70-90 sweeps and see
how that feels, all of my Pirellis have felt great so far
at any psi I've 'run', but this might be a quite interesting
test.
All the Pirellis I've used also felt perfectly stable at any speed with any psi.
The thing is, if you go fast, centrifugal force is going to play a part in how much your tires flex in a corner. You don't have that working for you at low speed. That's why I feel a very low speed test is the best indicator of minimum safe tire pressure. Also, tire temperature...if the tire gets hot from road surface or lots of flexion, that's going to make the air in the tire expand.
Here we go again, one of Rook's little stories better kept to himself...I rode a flat rear tire over a hundred miles. Don't do that, I'm just telling you it's possible even if extremely dangerous.. How is it possible? What I just said, the 2 psi of air left in the flat swells to 6 psi because the tire is so soft, the rubber is flexing and stretching the whole time just from being so soft. Also the centrifugal force thing. I didn't ride over 50 mph but that's plenty fast enough to throw the spinning tread out away from the axis with an appreciable amount of force. The flat tire keeps itself inflated. Yes indeed, I got off the bike and watched the obviously low tire flatten almost to the ground in about 20 seconds. It had a nail in it. It was very skittish even taking the large curves on the interstate. I totally felt the tire bending. It was quite hot to the touch when I got home. It needn't be mentioned but what if the nail came out or what if the bead broke? Likely crash. Im just telling you, I tried it and it worked that time.
Also, my first track day, after the first couple sessions, someone asked how the bike was handling. I told him the rear was sliding all over in the corners, it was scary. I never experienced anything like that on the street. He asked me the tire which was a Bridgestone BT-003 and told me to lower my tire pressure to some ridiculously low psi. This was the owner of the dealership I bought the bike from. I think it was 12 psi...maybe 8, front and rear. It worked. In my experience, Bridgestone tires are nothing special but in a track situation where the tire was melting, going way softer made a huge improvement. I guess the speed and heat. Hey, if it's melting hot, it's going to melt even more soft but at least the contact patch is larger. IDK what the combination was but it worked. Hey, my pics work again! 
No tire pressure I've ever used in street riding ever made nearly as much difference. I simply can't ride on the street as fast and for as long as I can on a track. Low tire pressure on the street is more a mental thing. I don't feel I can go any faster. Same with go fast parts and other mods, sometimes I feel them but I cant really use them.
08 MIDNIGHT SAPPHIRE BLUE ZX-14 Now Deceased, will be resurrected, 08 Hayabusa,
2024 ZX-14R bran friggin NEW and 2026 hayabusa!