60 series vs 70 series Goodyear Polyglas tires

What's the difference between the 60s and 70s tires ?, is it the over all tire width ,tread width , or height ?.

60 series is sidewall is 60% of the tread width, same with 70%. Same as modern tires.

It's called "aspect ratio"; the ratio of sidewall height to tread width, as described above.

The shorter sidewall cuts tire flex on turning. I seem to remember the 70s on performance cars on 14s and the super performance cars got 60 series tires on 15s.

R.

According to the chart I just googled, a G60 15 has a diameter of 26.46" and a G70 15 has a diameter of 27.46". Different letter sizes have different height differences, and then you need to take in the wheel diameter that also changes the differences. As I remember from back in the day, an F70 14 had about the same height as a G60 15, but that was a long time ago. Gene

the only thing wrong with using published dimensions, is the difference between tire manufacturers of a particular size can vary up to an inch.
i have witnessed and measured this countless times over the years.
also, keep in mind the difference between a "loaded" dimension vs an "unloaded" one.