more ?s about tires

[Bob Trevithick]

Andrew Duane USG wrote:

># tire_size 205/55ZR16 195/65QR15
>Specification  Sidewall  Radius  Diameter  Circumference  Revs/Mile
Difference
>205/55-16         4.4in  12.4in    24.9in         78.2in        811
0.0%
>195/65-15         5.0in  12.5in    25.0in         78.5in        807
0.4%
>
>So they are almost exactly the same size. 0.4% is insignificant.
>of quattro Diges

And Robert Myers wrote:

>The same calculations for the 205/55R16 give 406.4 + 2*(.55*205) =
631.9 mm
>or 63.19 cm or 24.88 inches.  Approximately 0.1 inch difference is
>essentially insignificant.  The tire salesman is correct.

Thanks very much, both of you!!  This is very reassuring, and I've
learned a lot.

Your help is very much appreciated.

Warm regards,
Bob