Date:         Fri, 15 May 1998 11:29:48 EDT
Reply-To:     Kim <Kim@AOL.COM>
Sender:       Vanagon Mailing List <Vanagon@vanagon.com>
From:         Kim <Kim@AOL.COM>
Subject:      Re: Wheels, Tires, Sizes...
Comments: To: Vanagon@VANAGON.COM
Content-type: text/plain; charset=US-ASCII

In a message dated 5/15/98 1:34:37 AM, jsilver@MAIL.AROS.NET writes:

>I've seen lots of postings re:wheels and tires, alloy wheels, different
>size
>tires, etc.  Excuse my ignorance, but I have a few basic Questions:
>What is the advantage of going to a 15" rim?  Isn't there a disadvantage
>to
>changing overall tire diameter, in terms of ride, handling, speedon and
>odometer readings?

It isn't just the diameter, but the width of the rim too that can be
'upgraded'. The stock wheels are 5 1/2 or 6 inches wide. With wider rims (and
larger diameter wheels) the advantage is usually that road grip is improved.
The disadvantage is that the ride may become harsher (depending on what size
tire you go to,) and less able to absorb those monster potholes without
damaging the wheel. A lower profile tire has less flex typically, than a
higher profile tire. The improved grip is why sports cars can corner so well.
The lower profile is why some sports cars also have such a harsh ride.

As to rolling diameter of wheel, which factors into odometer/speedometer
readings, changes of less than 5% are usually not important. It is possible to
change diameters of the wheel and go to a lower profile tire and come within a
few percent of the original diameter. For a 205 70 R14 tire (that is 205
millimeter wide tire, with a 70% sidewall profile on a 14 Inch rim) a
comparable change is to goto a 205 65 R 15. The difference in diameter is less
than 1% (the 15 is larger, fyi).

FYI, the Syncros have used 215 series tires on 15 or 16 inch rims.

And finally, the major effort in turning a wheel, is the weight at the OUTSIDE
(i.e. the tire). If a larger rim is alloy, it is usually lighter than the
steel. Going to a lower profile tire will usually result in a lighter (overall
weight) tire as well, so the larger wheel actually means it is LESS effort to
turn the wheel.

Esthetics are usually the real reason though, but as I've outlined there are
actual reasons for going to larger wheels (especially on cars).