*usually* if a tire has no apect ratio assigned, it is what as known as a 85
series tire - i.e the Michein Redline 185-15 would be a 185/85-15. (which it
Hope this helps.
> From: email@example.com (Pete & Aprille Chadwell), on 6/6/97 7:54 AM:
> It is my understanding that the proper OEM tire size for TR6 is not
> 185/70R15, but rather 185/15... no aspect ratio for this size. Otherwise,
> I could calculate the rolling circumference of the tires based on my
> understanding of the sizing nomenclature. My car is fitted with 185/70R15
> Bridgestone SF371s and they are too short. Someone told me once that the
> OEM size was closer to a 75% aspect ratio. Go find, for instance, the
> aspect ratio on a set of Michelin Redlines. I don't think they have one
> designated. They just say 185/R15. Anyone know more about this?
> Pete Chadwell
> 1973 TR6
> >Check out the site at www.powerdog.com/tiresize.cgi/. If you know the
> >tire size (i.e.- 185/70R15), this site will give you every dimension of
> >the tire you need. You can even list different size on the form and it
> >will do a comparison of circumferences indicating the difference in
> >percentages. This is useful if you want to go to another tire size
> >(wider?) with minimal effect on your speedo. Check it out!
> >Tony Childs
> >"72 Spitfire - Resurrected!