Re: tire size/stock rim - in response to Stewart

[Stewart MacLund <sundie@lunaticfringe.org>]

Eric Wang wrote:

> Stewart,
>
>      With all due respect, I think you've got it all mixed up.  The
> 205/215/195 etc. designation refers to the width of the tire, not the
> height.  The 55/50/45/40 etc. designation refers to the "height" (i.e.
> profile).

Oops.  You're absolutely correct.  Mea maxima culpa.

>      You also wrote, "Oh, and a larger rim provides for more tire tread
> on the ground, due to a larger diameter."  Not true at all.  The contact
> patch for a 17" rim / tires vs. the contact patch for 15" rim / tires,
> with width being constant, is almost the same.  The contact patch varies
> with width, not height.

Oops again.  I meant whole tire diameter, not just the rim.  In fact, i was
probably THINKING "A larger rim provides for less rubber with the same end
result, which is desirable".  And the contact patch DOES vary with height,
although much less than with width.  SImple geometry proves this.  If you
want an extreme example, go look at the contact patch on a Austin Mini vs
the contact patch on an 18wheeler.  Yes, i know, you wouldn't switch those
tires.  The example is only for demonstration.

SUndie...

ps - One thing, that i admitted in the message was probably incorrect, and
you tear me apart.  Well, a pox on your house.  :)