on 7/20/01 1:55 PM, Aristotle Sagan at killer_jupiter@HOTMAIL.COM wrote:

>> on 7/20/01 11:41 AM, Aristotle Sagan at killer_jupiter@HOTMAIL.COM wrote:
>>
>>> You have a couple of choices tire sizewize...
>>> 205R65-15 or 215R60-15 are both about the equivalent of a 195R78-14. The
>>> 185R7814 is a bit smaller.
>>>
>>> As your tire size (circumference) goes up, your speedo reads slower.
>>
>>
>> by what percentage?  i mean, if i am showing 65, i'm going what, 67?
>>
>> bill
>> '87 syncro westfalia
> Specification   Diameter       Circum      Revs/Mile    Diff
> 185/80-14        25.7in         80.6in        786        0.0%
> 215/60-15        25.2in         79.0in        802       -1.9%
> 205/65-15        25.5in         80.1in        791       -0.6%
> 195/75-14        25.5in         80.2in        790       -0.5%
> 205/70-14        25.3in         79.5in        797       -1.4%

ok, and 215/75-15 rims are 27.7" dia., 87" in circ., and 728 revs/mi, for a
difference of -8.0% from the stock tires/steel wheels.

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/