Originally Posted by
Sy Reene
Of course looking at that chart, you should also likely be comparing the 23s at 100 or so PSI to 32s at about 60psi. In addition from aero perspective, the assumption is generally all-else-being equal. Ie. a bike that's built to take 32mm+ tires, conceivably isn't going to be as aero as a bike built that could only take max 25mm tires. Nor could said bike likely be built to the same weight as a bike that hasn't been built to take only narrower tires. IOW, there's a number of factors.
right; my recent experience has been riding on 26, 28, and 30mm tires on a bike which takes 32mm max; obviously everything else is the same in this case. i run pretty low pressures relative to the recommendations, so i was likely looking at 10.5 watts ish on the 30mm, and maybe 9.5 watts on the 28. i haven't done the math but i have to imagine the increased frontal area and the less optimum rim/tire profile is way way more than a watt, which is really splitting hairs for anyone but the most pro!