Re: Tire Sizes - Help for the math impaired

["Csank" <csank@domain.elided>]

Russ,

You are right, of course!  I guess the trick is to get a diameter measurement
for any tire before you buy.
  Doug, Alex and all,
        I agree with Doug's calculations as far as they go.  The problem is,
the manufacturers have not figured out that that is how they are supposed to
build the tires.  Not all 185 70 14 tires are created equal.
        I once measured a bunch of tires just to see how they compared.  For
ease of measurement, I measured the circumference with a cloth tape.  They
were not all the same, even if marked the same size.
        For all intents and purposes, the 165 14 (165 80 14), the 185 70 14,
the 195 65 14, the 205 60 14, the 195 60 15 and the 225 50 15 are ALL close
enough to the same diameter to work on our Alfas.  The variation in diameter
is probably less than the error in the speedometer anyway.
        You do time Interstate mileage markers to re-calibrate the brain to
speedometer interface every time you buy new tires don't you?  I do.

  Ciao,
  Russ Neely
  Oklahoma City

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