All the specs on tyres (tires) and wheels seemd to be about as clear as the correct Masonic handshake. Everyones got an idea: they all seem to contradict each other.

I'm looking to change my wheels, and hence my tyres. I'm going up to 17 inch, probably the same width or slightly wider. So for arguments sake lets assume the rears will be the same width (8.5 inch n'est pas?). Tyres will probably be S02 PP or Yoko AVS

The most important thing to me is the rolling circumference (and hence the diameter). This is so that my speedo is correct, and my performance isn't diminished.

How do I work out what size tyres to buy taking into account width and aspect ratio of the current and new tyres?

 

http://www.miata.net/garage/tirecalc.html

All you need to know.

 

Dang, well that's the end of this thread

 

Yep. It is.

 

[QUOTE]Originally posted by AusS2000:
[B]Dang, well that's the end of this thread

 

Winning recipe:

Mix forged wheels with a length and width increase of one inch.

Use hubcentering rings if and only if you cannot source hubcentered wheels. They keep well so look beyond your local market...

Reduce the offsets by no more than 10 milimeters.

Pepper with 215/45/17 of soft rubber at the front and 245/40/17 at the back.

Serve piping hot.

... and accept no substitutes!