Originally Posted by
HTupolev
If you're using an aero rim specifically designed for 28mm tires, like an ENVE 4.5 AR, then the change would allow the rim's aero design to function correctly, which could give you a small but perhaps measurable improvement.
Otherwise, not really. What mostly matters on the road is how a tire is made, not its dimensions, and a 14% width difference is pretty small in any case.
...a 14% change in width represents a 30% change in cross-sectional area and a similarly large difference in volume....not really small.
Either way, going to 28 over 32 really won't gain you anything. And will harm handling and looser-pack surfaces-should you encounter them. A no-win/lose scenario.