If you asked each racer in the TSSC paddock what their tyre pressures were (and they answered honestly) you'd get everything from 18Psi to 28Psi
and they are all using the same tyre for the same purpose.
So I'm not surprised you are getting conflicting figures. You are trying to get as large a contact patch as you can - too high and you end up
sitting on the middle of the tyre and too low you end up sitting on the rims. Neither is really any good.
Either side of the optimum pressure you will lose grip, but you will lose more grip for being a pound under than you will lose for being a pound
over - so if you are not sure you should err to a higher pressure.
All tyres makes require different pressures/set ups and all tyre sizes require something different again (bigger the tyre the lower the
pressure).
And the real 'kick in the teeth' is - even when you have the pressures perfect - if it rains then you have to change them again. What fun....
NiG
http://www.niginthecar.net