Re: snow tire size.

[PDQSHIP@aol.com]

In a message dated 95-11-26 11:09:39 EST, you write:

>
>I received a message from the post master that the following message never
>got posted.  Come to think of it, I never did get "my copy" of the message
>either.  That being said, here comes the questions once again!  As it is now
>snowing in Toronto, any and all responses would be apprecated.
>
>The summer tires on my Audi are 205/55/16.  I know that I can get 15 inch
>tires around the calipers so the question is.... what is the correct size
>winter tire?  I think that it is 195/65/15 but I am not sure.  Any help
>would be appreciated!
>
>Also, what is the mathematical formula to determine what size of tires are
>equivalent!
>
>

205/55 16 means:

205/25.4 = 8.07 tire width
then
8.07 X .55 (aspect ratio = height relation to width) = 4.44 X 2 (rim to
ground and rim to top of tire) = 8.88
then
8.88 + 16 (inch wheel) = 24.88 tire diameter

so

a 195/65 15 will give you a 24.98 diameter or .05" higher height

a 205/60 15 will give you a 24.68 diameter or .1" higher height

So

either one will work with very little, if any speedo error......  My 5ktq
runs 205/55  on 16X7.5's in the summer and 205/60 on 15X7's in the
winter.....  Me, I would take the 60's, the 65's tend to float too much at
higher speeds, most snows are not known for sidewall stiffness.......

HTH

Scott