Just moved from 23 to 25mm tyres. Im 92kgs in weight. I used to run the 23's with 120psi rear and 100 front. Would it be sensible to go to 110 rear and 90front on the 25's? What pressure do you guys use?
Tyre pressure should be somewhere in a range between teeth-shattering hard and just enough pressure to not (often) bump through and get pinch flats. This is arrived at experimentally and dependent on your weight, the terrain you're on and your tolerance for discomfort. Only you can decide what it should be.
Further, a tyre's maximum pressure is size-dependent. All else being equal, a wider tyre will pop off the rim at a lower pressure than it's equivalent skinnier cousin. Pressure is accumulative at the bead - a wider tyre has more surface area and the total force acting on the bead is thus potentially larger than that for a narrower tyre.