David (everyone), you might find this useful/interesting on this issue...
http://sheldonbrown.com/
> Both measurements, across and off the rim, were smaller.
> Why is this? Have the numbers come to represent something different?
> have tires come to reflect the overall cultural obesity situation or is
> there some other "inflationary" cause for this? Anyone else notice this
> in older tires? Was this a gradual change or did I miss a tire sizing
> revolution somewhere?
> Dave Boston
> Tucson AZ USA