Originally Posted by
Airbrushkid
So there's no way to determine the actual outside diameter of the different width tires until I buy each one?
When inflated the tires cross-section is fairly round. So in principle the 23mm tires would have an outside diameter of about 622mm (diameter of rim) + 2 x 23mm = 668mm or 26.3" whereas the 45mm tires would have an outside diameter of 712mm or 28". But in practice the actual widths vary some between different tire makes and models and it'll also vary a little depending on the width of the rim on which the tire is mounted