Hello,

I ordered for my RX-8 the Michelin Pilot Alpin 225/40R18.

I'm not a tire GURU, did I ordered the right size ? I'm just concerned about the 40 instead of 45...!

Thanks

Simon.

40 will make the tyre lower profile than the normal tyres.

And according to http://www.miata.net/garage/tirecalc.html your speedo will read 3.4% to fast.

It'll probably adversly affect your cars handling and mebee make it easier to damage your wheels too. And you may also need different(higher?) tyre pressure.


Edit : -

Tyre numbers :

225 - width in mm.
40 or 45, tyre wall height as percentage of width, i.e. 50 is half the width as wall height.