Originally Posted by
RockiesDad
So what about going to 30mm or even 32mm? Are we hitting the point of diminishing returns going up in size for road bikes???
IMO, this is going to be determined by your weight, your roads and your comfort threshold.
For me, once I get to about 65psi, there's very little benefit of going lower, regardless of tire size (if we're talking strictly paved roads), it just doesn't meaningfully add to my comfort, so going bigger than 28/30 is just adding more rotating mass and a larger frontal section (though how much of an aero detriment this is depends on other things, too, like tire/rim profile).
If lighter guys feel perfectly comfortable at 80psi on 25mm tires, cool - in that position, I wouldn't up-size either. If heavier guys need 32s to run at their desired pressure, that's understandable, too.