Don Q wrote:
> On 2010-09-15 09:29:30 -0400, Arye > said:
>
>> It's true that that 185 and 195 indicate the tread width. However,
>> the 60 indicates the ratio of diameter to width, so it goes up
>> proportionally.
>
> Strictly speaking you are correct of course.
> However, 60% of 185 versus 60% of 195?
>
> Without going into heavy (for me) math, I will speculate that the
> difference in diameter will come to about 2%. If I'm going 51 and my
> speedometer is showing 50, I can certainly live with that margin of
> error.
>
> cheers

As many do.