Buying Tires with new rims. What exactly does the " 245/40 - 18 "mean? 99' Mustang ?

[Kenny]

well i'm purchasing new 18" rims with tires along with it. I know that the 18 means how large the rim would have to be but what about the other 245/40? Would you suggest this for a 99' Mustang? looking to get Anthracite F500 rims.

[ClTech]

245 = the width of the tire tread in milimeters. 40=the aspect ratio meaning the sidewall height is 40% of the tread width. You are looking at a wide low profile tire. It should improve your handling, be careful of pot holes - the low profile means the rim is closer to the ground. The Anthracite rims look good!

[peopleareidiots]

245 is the width of the tire in millimeters, and the 40 is the height of the sidewall: 40% of 245 mm.