<VV> Tire gurus - What kind of tires do I have?

[Bruce Schug]

On Mar 26, 2005, at 11:22 PM, Charles Lee wrote:

> Since you're changing from stock anyway, why not put something besides 
> "taxi" tires ("80" series is the tread to height proportion,

*SNIP*

No, no, no, no, no!!!!!

I keep seeing this in a post every so often.

The aspect ratio is NOT the ratio of the tread width to the height. IT 
HAS NOTHING TO DO WITH TREAD WIDTH!

The aspect ratio (80, 70, 60, etc.) is the ratio of the SECTION WIDTH 
to the height, not the tread width. Wherein section width is the widest 
part of the tire when mounted and inflated. If you have a 185/80-13 
tire, the section width is 185. If you have a 7.00-13 tire, the section 
width is 7.00. "Height" here refers to the height from the tread to the 
wheel. The diameter equals twice this height plus the diameter of the 
wheel. Tread width has nothing to do with these dimensions. At least 
nothing directly.

Bruce

Bruce W. Schug
CORSA South Carolina
Greenville, SC
bwschug at charter.net

CORSA member since 1981

'67 Monza. "67AC140"