Hey I'm soon going to be in possession of some 18" saleens and just wanted to know what are the performance/gas mileage etc effects if there are any. thanks.

 

What is your current tire circumference vs. the newer one? You can actually have 17" rims with tires that has the same circumference as 18" rims with different tires.

 

there 245-35-17 i think

 

That would mean that your tire's diameter is 23.752 inches. Do you know what the other tires would be for size (on the 18's?) Once we have both numbers, you can figure out which will give better gas mileage, etc.

 

245/35 is a low profile, it should be 245/45 for our stangs.

 

That would make the diameter 25.681

 

ok, here is the truth, with tires that have the same circumfrence, the 18 inch wheel will produce better cornering speeds and G loading in cornering on a smooth surface due to less sidewall flex. A 17 inch wheel also provide very good cornering speeds and G loading, but on a street, due to sidewall flex will provide a smoother ride since the tire is the first part of the suspension.

 

OK here's the right numbers...

17" : 245/45-17

18" : 265/35-18

There we go, so will there be any performance/mileage changes etc...
(thanks twister for the info)

 

your 60 foot times will also drop due to less mechanical grip

 

and i also heard that with bigger wheels you get a higher top speed but lower acceleration.