Originally Posted by
Steev
The 23 or 25 measurement is the nominal width of the tire. Tires rarely measure out to their nominal width. 2mm is 0.078". You will barely notice a difference.
For that small of a change there is no need to change inner tube, they stretch, a lot if necessary.
Whether a tire is harder to install is more a question of the type of bead of variances between manufacturers.
This.
Hell, in a pinch, I've thrown a 700x28 tube in a 2" mtb tire before.
For me, the main difference between a 25mm and 23mm tire, is running a lower psi in the 25 giving a slightly cushier ride.