what size would you recommend---the wheels are 20x8.5---is the wheel size ok----pls advise and thanks

 

Just got a set of 20" myself... the Porsche factory size is 275/40/20 which is what I got in the Yokohama Parada Spec-X. Very happy with them.

David

 

275/40/20 vs 275/45/20 - Obviously the 40 is lower p + superior handling and the 45 fills the wheel well a bit better. ? is, anyone here ever flip between the 2 sizes? Pros / Cons???

 

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

Here is a great tool you can see how it would look like, sure it would fill up the wheel well a bit but your speedometer would be affected by this.

"275/40/20 vs 275/45/20
Speedometer reading with non-stock tire is 3.8 too slow.
When your speedo reads 60mph, you are actually travelling 62.3mph."

I wonder,,,,, does this mean you get 2.3miles free (per hour)?

 

Thanks. Look like the math in both cases is close enough. I most likely would opt for the 45 Series as the 40 series is almost 1" shorter in the sidewall. That's fine for looks but ride . . . .ug.

 

on a 20 the 275 45 looked dis proportionate maybe better would be 275 45 22

 

In fact, Audi Q7 4.2 premium comes with 275/45/20 tires on oem 20" rims.