Late 60s early 70s Tire size specs - questions

[cadillacmike68]

I'm puling this out of the 1970 tire thread over in general because it'll get lost in the shuffle there.

In 1968-1969 the tires used were designated 9.00 x 15 Load Range B with no aspect ratio defined - was it 80%, 78%, something else?
The Fleetwood 75 sere spec's at 8.20 x 15 load range D.

That 9.00 or 8.20 is the cross section in inches, which by the way is 228.6mm and 208.28mm just to keep this in perspective, because a couple years later the the same cars got 235-75-15 (again two different load ranges) as the specified tire size, the 235 being the cross section in mm. 235mm is 9.25 inches.

In 1970 what I suspect is the same sized tire got the tire got the size spec of L78 - 15 (load range B). Here we have no cross section width specified. It is interesting to note that both in all three years, 1968-70, the Fleetwood 75 have 8.20x x15 Load range D specified, while 1970 has L78-15 (load range D) right there next to the 8.20x15 (LR D) for the Fleetwood 75s.

So
L78-15 load range D is equivalent to 8.20 x 15 LR D while
L78-15 LR B is equivalent to 9.00 x 15 LR B.

That is two different cross sectional widths!!!

Maybe the 8.20 LR D has a higher aspect ratio than the 9.00 x 15 LR B ?? But neither are ever mentioned anywhere that I can find.

Now for the question:

Bill Refakis, or anyone who knows:

Do you or any one here know that the aspect ratio on the 1968-69 (and earlier) 9.00 x 15 tires (and 8.20 x 15LR D) was and / or the Cross-sectional width of the L78-15 tire (both load ranges) was?