> From: Bob Lang [SMTP:LANG@ISIS.MIT.EDU]
> Sent: Thursday, May 21, 1998 1:18 PM
>
> As for the "rule of thumb", you are referring to what the tire guys call a
> "plus one" and "plus two" tire... thus, a 185/80 would be about the same
> diameter as a 195/75 (plus one) or a 205/70 (plus two).
>
I have to disagree on this one Bob. I always thought that the +1, +2, etc.
designation refers to maiantining the same rolling diameter but increasing
the *wheel* size by 1" (+1), 2" (+2), etc. Thus a +1 upgrade to a TR6 would
be a xx/xxx-16 where I don't know off hand which xx values result in the
same rolling diameter as the 185/80-15. But you would end up with a much
lower profile tire. More stick (due to stiffer sidewalls since they are not
as tall) but also more pain or a harsher ride (less air to cushion the road
imperfections).
At least that is what is seems to mean in the GTI world. I think Tire Rack
explains this on their site.
Peter Zaborski
76 TR6 (CF58310 UO) (Michelin redlines in original size)
87 GTI (185/60-14 - stock size)
Calgary AB Canada
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