There was a question about 28 inch tyres, a week or two ago. Now I can't find it, tsk, tsk. I did find some info. posted to another list sometime ago, and which I did write down, so here goes:<br /><br /> There are at least four or five different sizes in the 28 inch family of tyres.<br /><br /> 700 647 28 x 1 1/4" Very Rare. <br /> 700 A 642 28 x 1 3/8 " Very common, on old bikes.<br /> 700 B 635 28 x 1 1/2 " Not so common.<br /> 700 C 622 28 x 1 3/4 " Widespread, 'modern' size.<br /><br />Note that the now obsolete 27 x 1 1/4 size has a Bead Seat Diameter of 630 m/m , but it is not included in the 28 inch family. It was an odd size created by<br />Dunlop. Confused? So was I. Ciao.