I've seen the diameter vary with the same manufacurer in different tire models. A 195/75 in one line would have differnet revs per mile than the 195/75 in a different line, and not by just 1 or 3 either. Ken Ames Quoting Jim Blair <carnuck@xxxxxxxxxxx>: > A: I'll have to check around to see if I can find the link. > > > From: john <john@xxxxxxxxxxxxx> > Subject: Re: fsj: Re: 67 Wagoneer Questions > > so a 235/75r15 should be 28.8 inches when new? > > is there a source on line that mandates the official size for each tire > size? > that would be handy to have... I thought it varied a bit from mfr to > mfr... > > john > > > On Mon, 27 Sep 2004, Jim Blair wrote: > > >-->They are 28.8" when new. That was DOT requirement that all sizes be > >matched, > >-->unlike when numbered or lettered sizes were the norm. They were allowed > >to > >-->round up or down back then, and a tire from the beginning of a btach > >could > >-->be up to 1" different than one from the end of the batch! (remember > >-->Firestone 500s? They were caused by some of the other bigger companies > >-->manipulating the rubber market so that they got poor quality rubber) > > > > > > ------------------------------------------------- This mail sent through IMP: http://horde.org/imp/