a 26inch wheel when spinning at 80 roations per minute (20km/h or 12mph) will have a Centripetal Acceleration of about 5g (G-Force) on the outermost spot. That does not make the wheel "heavier", but due to the gyroscopic effect and air resistance loose ever more energy, when spinning faster.
Fun wheel videos: https://www.youtube.com/watch?v=GeyDf4ooPdo https://www.youtube.com/watch?v=ty9QSiVC2g0