Low profile tires can compensate for increased wheel diameter.  I have 18"
Konig wheels on my 97 Golf, but the outside diameter of my tires is only 3%
larger than stock.

Isaac Taylor

----- Original Message -----
From: "Larry Alofs" <lalofs@ENTERACT.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, July 21, 2001 6:09 PM
Subject: Re: 15" wheels effect on speedometer?

> Bill Kasper wrote:
>
> > i assume the speedo was calibrated for the 185/80-14 size?  if so, then it
> > means when i see 65 mph on my speedo i am actually doing 8% faster, or 70.2
> > mph?
> >
> > that's good to know, especially when i am in speedtrapland.
> >
> > thanks.
> >
> > bill
> > '87 syncro westfalia
> > http://www.scruznet.com/~kasper/pics/westy/
>
> You can check with a time-speed-distance calculation.
>   Next time you're on an expressway or toll road with marker signs 1
> mile apart,
> hold the speed steady and measure how many seconds to go a mile.
>
> At 60 mph it should take 60 seconds
> At 72 mph it should take 50 seconds.
> etc.
>
> Divide the seconds into 3600 to get the mph or vise-versa.
> Basic physics.
>
> Larry A.
> Chicago