I am just going by tire diameter, not odometer set-up.

I calculate tire outside diameter to be approximately the 
following:

	185R14   25.9"    0%
     195/70R14   24.7"   -5%
     195/75R14   25.5"   -2%
     205/70R14   25.3"   -2%
    27X8.50 14   27.0"   +4%
        225R14   28.5"  +10%

Now, all mechanical speedometers are typically 
conservative by approx. 2%.

So, with 27X8.50 14 tires, I would expect the speedometer 
is reading 2% slower than with 185R14.  At an indicated 65 
MPH, that's 1 MPH or an actual speed of 66 MPH.

--- On Wed, 5 Mar 1997 12:10:25 -0500 (EST)  
SyncroHead@aol.com wrote:

>In a message dated 97-03-04 22:22:49 EST, 
mdstockr@neo.lrun.com (mdstockr)
>writes:
>
>> 
>>  TIRE SIZES
>>  ----------
><snip>
>>   27X8.50 14   1*
>>       225R14   1*
>>  
>>    * These tires have diameters smaller/larger than 
original
>>      You will see speedometer/odometer errors
>
>My experience with the 27x8.50R14 BFGoodrich Radial All 
Terrains is that they
>actually eliminated my odometer error.  Previously my 
smaller tires over
>estimated distances.  Now whenever I measure my odometer 
against the highway
>odometer check signs I'm off my .05 miles or less over 5 
miles of
>measurement.  That's about 1% or less from actual.
>
>Jim Davis
>87 GL Syncro
>88 GL Wolfsburg
>

-----------------End of Original Message-----------------

________________________________________________

  Michael Stocker <mdstockr@neo.lrun.com>
  North Canton, Ohio, USA     Time: 1:42:52 PM
  LiMBO / GASS                Date: 3/5/97
  1989 Audi 90 Quattro
  Wanted: Nice 1968-> air cooled or diesel
  Previous VW's: '66-T3, '67-T1 & '70-T2 Westi
________________________________________________